Method 1698: Steroids and
Hormones in Water, Soil, Sediment,
and Biosolids by HRGC/HRMS
December 2007
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Method 1698 December 2007
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
EPA-821-R-08-003
December 2007
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Method 1698 December 2007
Introduction
EPA Method 1698 determines steroids and hormones in environmental samples by isotope dilution and
internal standard high resolution gas chromatography combined with high resolution mass spectrometry
(HRGC/HRMS). EPA Method 1698 was developed for use with aqueous, solid, and biosolids matrices.
Disclaimer
This method has been reviewed by the Engineering and Analytical Support Branch of the Engineering
and Analysis Division (EAD) in OST. The method is available for general use, but has not been
published in 40 CFR Part 136. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
Contacts
Questions concerning this method or its application should be addressed to:
Brian Englert, Ph.D.
Environmental Scientist
Engineering & Analytical Support Branch
Engineering and Analysis Division (4303T)
Office of Science and Technology, Office of Water
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue NW
Washington, D.C. 20460
http://www.epa.gov/waterscience
ostcwamethods@iepa.gov
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Method 1698 December 2007
Table of Contents
Introduction iii
1.0 Scope and Application 1
2.0 Summary of Method 2
3.0 Definitions and Units of Measure 3
4.0 Interferences 3
5.0 Safety 5
6.0 Equipment and Supplies 6
7.0 Reagents and Standards 10
8.0 Sample Collection, Preservation, and Storage 14
9.0 Quality Control 16
10.0 Calibration and Standardization 20
11.0 Sample Preparation 25
12.0 Extraction and Concentration 31
13.0 Cleanup and Derivatization 37
14.0 HRGC/HRMS Analysis 39
15.0 System and Laboratory Performance 40
16.0 Qualitative Determination 42
17.0 Quantitative Determination 43
18.0 Analysis of Complex Samples 46
19.0 Pollution Prevention 47
20.0 Waste Management 47
21.0 Method Performance 47
22.0 References 48
23.0 Tables 49
24.0 Glossary 61
IV
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Method 1698 December 2007
25.0 Definitions and Acronyms 62
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Method 1698 December 2007
EPA Method 1698
Steroids and Hormones in Water, Soil,
Sediment, and Biosolids by HRGC/HRMS
1.0 Scope and Application
1.1 EPA Method 1698 is for determination of steroids and hormones in multi-media
environmental samples by high resolution gas chromatography combined with high
resolution mass spectrometry (HRGC/HRMS).
1.2 This method was developed for use in Clean Water Act (CWA) programs; other
applications are possible. Technologies and quantitation techniques in this method are
based on existing EPA methods (Reference 1) and on procedures developed at Axys
Analytical (Reference 2).
1.3 The target analytes that may be measured by this method and their corresponding
Chemical Abstracts Service Registry Numbers are listed in Table 1.
1.4 The detection limits and quantitation levels in this method are usually dependent on the
level of interferences rather than instrumental limitations. The method detection limits
(MDLs; 40 CFR 136, appendix B) and minimum levels of quantitation (MLs; 68 CFR
11790) in Table 2 are the levels at which steroids and hormones can be determined in the
absence of interferences.
1.5 This method is restricted for use by analysts experienced in HRGC/HRMS or under the
close supervision of such qualified persons. Each laboratory that uses this method must
demonstrate the ability to generate acceptable results using the procedure in Section 9.2.
1.6 This method is performance-based which means that you may modify the method to
improve performance (e.g., to overcome interferences or improve the accuracy or
precision of the results) provided that you meet all performance requirements in this
method. These requirements for establishing equivalency of a modification are in
Section 9.1.2. For Clean Water Act (CWA) uses, additional flexibility is described at 40
CFR 136.6. Modifications not in the scope of Part 136.6 or in Section 9 of this method
may require prior review and approval.
1.7 Some of the compounds in this method are controlled substances. Laboratories
performing this method should have all appropriate licenses and certifications and obtain
all needed standards and chemicals from licensed sources. For some of the compounds in
this method it may be necessary for laboratories to obtain a DEA license.
1.8 This method does not measure steroid conjugates.
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Method 1698 December 2007
2.0 Summary of Method
This method involves solvent extraction of the sample, followed by cleanup with a layered
alumina/Florisil column, and an option to remove sulfur using copper. Following cleanup, the
target analytes are derivatized to make them sufficiently volatile for analysis by GC/HRMS.
Quantitation is performed by isotope dilution and internal standard techniques, depending on the
analyte and the availability of labeled analogs. These procedures are summarized below.
2.1 Extraction
2.1.1 Aqueous samples absent visible particles - Stable isotopically labeled analogs of
the steroids and hormones are spiked into a 1-L sample. The sample is extracted
with methylene chloride using separatory funnel extraction (SFE) or continuous
liquid/liquid extraction (CLLE).
2.1.2 Solid and semi-solid samples, including aqueous samples with visible particles
(excluding biosolids) - The labeled compounds are spiked into a sample aliquot
that contains 10 g dry weight of solids. Mixed-phase aqueous samples are
filtered. The aqueous phase is extracted as above (Section 2.1.1). Solids are
ground or homogenized (if required), mixed with anhydrous sodium sulfate,
dried for a minimum of 30 minutes, and extracted for 16-24 hours using
hexane:acetone in a Soxhlet extractor.
2.1.3 Biosolids - The labeled compounds are spiked into a sample containing 0.25 g
(dry weight) of solids. Cholesterol-d7 is spiked at a concentration 10 times
higher than in solid and semi-solid samples to account for the high concentration
of cholesterol found in biosolids. The sample is mixed with anhydrous sodium
sulfate, dried for a minimum of 30 minutes, and extracted for 16-24 hours using
hexane:acetone in a Soxhlet extractor.
2.2 Cleanup - If necessary, extracts from aqueous and solids samples can be cleaned up
using a layered alumina/Florisil column. If necessary, copper is used to remove sulfur.
Use of layered alumina/Florisil may not be required for some aqueous samples.
2.3 Derivatization
Following cleanup, the sample extract is concentrated to approximately 0.1 mL. The
solvent is exchanged to pyridine and the steroids/hormones are derivatized to their
trimethylsilyl-ethers using 7V,O-Bis(trimethylsilyl) trifluoroacetamide with
trimethylchlorosilane (BSTFA:TMCS). A labeled injection internal standard (Pyrene-d10)
is spiked into the extract and the final volume is adjusted to either 500 joL for complex
wastewaters (e.g., untreated effluents, in-process streams) or samples containing solids,
or to 20 \\L for clean wastewaters (e.g., ambient waters, finished drinking waters,
secondary biologically treated effluents).
2.4 GC/HRMS Analysis
2.4.1 An aliquot of the extract is injected into the gas chromatograph (GC).
The analytes are separated by the GC and detected by a high-resolution
(35,000) mass spectrometer. Two exact m/zs are monitored for each
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Method 1698 December 2007
steroid, hormone, and labeled compound throughout a pre-determined
retention time window.
2.4.2 An individual steroid or hormone is identified by comparing the GC
retention time and ion-abundance ratio of two exact m/zs with the
corresponding retention time of an authentic standard and the theoretical
or acquired ion-abundance ratio of the two exact m/zs. A compound is
identified when the retention times and ratios agree.
2.4.3 Quantitative analysis is performed in one of two ways using selected ion
current profile (SICP) areas:
For a steroid or hormone for which a labeled analog is available, the
concentration is determined using the isotope dilution technique. For a
steroid or hormone for which a labeled analog is not available, the
concentration is determined using the internal standard technique.
The concentrations of the labeled compounds are determined using the
internal standard technique and the recovery of each labeled compound is
compared to acceptance criteria provided in Table 5.
Additional labeled compounds may be incorporated into this method and
the concentration of the native compound may be determined using the
isotope dilution technique provided that all performance requirements in
this method are met. Requirements for establishing equivalency are
given in Section 9.1.2, and additionally for CWA uses, at 40 CFR 136.6.
2.5 The quality of the analysis is assured through reproducible calibration and testing of the
extraction, cleanup, derivatization, and HRGC/HRMS systems.
3.0 Definitions and Units of Measure
Definitions and units of measure are given in the glossary at the end of this method.
4.0 Interferences
4.1 Solvents, reagents, glassware, and other sample processing hardware may yield artifacts,
elevated baselines, and/or lock-mass suppression causing misinterpretation of
chromatograms. Specific selection of reagents and purification of solvents by distillation
in all-glass systems may be required. Where possible, reagents are cleaned by extraction
or solvent rinse.
4.2 Proper cleaning of glassware is extremely important, because glassware may not only
contaminate the samples but may also remove the analytes of interest by adsorption on
the glass surface.
4.2.1 Glassware should be rinsed with solvent and washed with a detergent solution as
soon after use as is practical. Sonication of glassware containing a detergent
solution for approximately 30 seconds may aid in cleaning. Glassware with
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Method 1698 December 2007
removable parts, particularly separatory runnels with fluoropolymer stopcocks,
must be disassembled prior to detergent washing.
4.2.2 After detergent washing, glassware should be rinsed immediately, first with
methanol, then with hot tap water. The tap water rinse is followed by another
methanol rinse, then acetone, and then methylene chloride.
4.2.3 Baking of glassware in a kiln or other high temperature furnace (300 - 500 EC)
may be warranted after particularly dirty samples are encountered. The kiln or
furnace should be vented to prevent laboratory contamination by steroid/hormone
vapors. Baking should be minimized, as repeated baking of glassware may cause
active sites on the glass surface that may irreversibly adsorb the steroids and
hormones. Volumetric ware should not be baked at high temperature.
Silanization may also be used to deactivate active sites on glassware.
4.2.4 After drying and cooling, glassware should be sealed and stored in a clean
environment to prevent accumulation of dust or other contaminants. Store
inverted or capped with aluminum foil.
4.2.5 Immediately prior to use, the Soxhlet apparatus should be pre-extracted for
approximately 3 hours and the extraction apparatus should be rinsed with the
extraction solvent.
4.3 All materials used in the analysis must be demonstrated to be free from interferences by
running reference matrix method blanks (Section 9.5) initially and with each sample
batch (samples started through the extraction process on a given 12-hour shift, to a
maximum of 20 samples).
4.3.1 The reference matrix must simulate, as closely as possible, the sample matrix
under test. Ideally, the reference matrix should not contain the analytes in
detectable amounts, but should contain potential interferents in the concentrations
expected to be found in the samples to be analyzed.
4.3.2 When a reference matrix that simulates the sample matrix under test is not
available, reagent water (Section 7.6.1) can be used to simulate water samples;
playground sand (Section 7.6.2) or white quartz sand (Section 7.3.2) can be used
to simulate soils and biosolids.
4.4 Interferences co-extracted from samples will vary considerably from source to source,
depending on the diversity of the site being sampled. Interfering compounds may be
present at concentrations several orders of magnitude higher than the analytes in this
method. The most frequently encountered interferences are humic and other acids,
particularly in biosolids. Because very low levels of steroids and hormones are measured
by this method, elimination of interferences is essential. The cleanup steps given in
Section 13 can be used to reduce or eliminate these interferences and thereby permit
reliable determination of the steroids and hormones at the levels shown in Table 2.
4.5 Each piece of reusable glassware should be numbered to associate that glassware with the
processing of a particular sample. This will assist the laboratory in tracking possible
sources of contamination for individual samples, identifying glassware associated with
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Method 1698 December 2007
highly contaminated samples that may require extra cleaning, and determining when
glassware should be discarded.
5.0 Safety
5.1 The toxicity or carcinogenicity of each chemical used in this method has not been
precisely determined; however, each compound should be treated as a potential health
hazard. Exposure to these compounds should be reduced to the lowest possible level.
5.1.1 Some steroids or hormones may be human or mammalian carcinogens. On the
basis of the available toxicological and physical properties, pure standards of the
compounds should be handled only by trained personnel thoroughly familiar with
handling and cautionary procedures and the associated risks.
5.1.2 It is recommended that the laboratory purchase dilute standard solutions of the
analytes in this method. However, if primary solutions are prepared, they should
be prepared in a hood, and aNIOSH/MESA approved toxic gas respirator may be
necessary when high concentrations are handled.
5.2 This method does not address all safety issues associated with its use. The laboratory is
responsible for maintaining a current awareness file of OSHA regulations regarding the
safe handling of the chemicals specified in this method. A reference file of material
safety data sheets (MSDSs) should also be made available to all personnel involved in
these analyses. It is also suggested that the laboratory perform personal hygiene
monitoring of each analyst who uses this method and that the results of this monitoring
be made available to the analyst. Additional information on laboratory safety can be
found in References 3-5. The references and bibliography at the end of Reference 5 are
particularly comprehensive in dealing with the general subject of laboratory safety.
5.3 The pure steroids/hormones and samples suspected to contain high concentrations of
these compounds are handled using essentially the same techniques employed in handling
radioactive or infectious materials. Well-ventilated, controlled access laboratories are
required. Assistance in evaluating the health hazards of particular laboratory conditions
may be obtained from consulting laboratories and from State Departments of Health or
Labor, many of which have an industrial health service. Each laboratory must develop a
strict safety program for handling these compounds.
5.3.1 Facility - When finely divided samples (dusts, soils, dry chemicals) are handled,
all operations (including removal of samples from sample containers, weighing,
transferring, and mixing) should be performed in a glove box demonstrated to be
leak tight or in a fume hood demonstrated to have adequate air flow. Gross
losses to the laboratory ventilation system must not be allowed. Handling of the
dilute solutions normally used in analytical and animal work presents no
inhalation hazards except in the case of an accident.
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Method 1698 December 2007
5.3.2 Protective equipment - Disposable plastic gloves, apron or lab coat, safety
glasses or mask, and a glove box or fume hood adequate for radioactive work
should be used. During analytical operations that may give rise to aerosols or
dusts, personnel should wear respirators equipped with activated carbon filters.
Eye protection (preferably full face shields) should be worn while working with
exposed samples or pure analytical standards. Latex gloves are commonly used
to reduce exposure of the hands. When handling samples suspected or known to
contain high concentrations of the compounds, an additional set of gloves can
also be worn beneath the latex gloves.
5.3.3 Training - Workers must be trained in the proper method of removing
contaminated gloves and clothing without contacting the exterior surfaces.
5.3.4 Personal hygiene - Hands and forearms should be washed thoroughly after each
operation involving high concentrations of the analytes of interest, and before
breaks (coffee, lunch, and shift).
5.3.5 Confinement - Isolated work areas posted with signs, segregated glassware and
tools, and plastic absorbent paper on bench tops will aid in confining
contamination.
5.3.6 Waste handling - Good technique includes minimizing contaminated waste.
Plastic bag liners should be used in waste cans. Janitors and other personnel
should be trained in the safe handling of waste. See Section 20 for additional
information on waste handling and disposal.
5.4 Biosolids samples may contain high concentrations of biohazards, and must
be handled with gloves and opened in a hood or biological safety cabinet to
prevent exposure. Laboratory staff should know and observe the safety
procedures required in a microbiology laboratory that handles pathogenic
organisms when handling biosolids samples.
6.0 Equipment and Supplies
Note: Brand names, suppliers, and part numbers are citedfor illustration purposes only. No
endorsement is implied. Equivalent performance may be achieved using equipment and
materials other than those specified here. Demonstration of equivalent performance that
meets the requirements of this method is the responsibility of the laboratory.
6.1 Sample bottles and caps
6.1.1 Liquid samples (waters, sludges and similar materials containing 5 percent
solids or less) - Sample bottle, amber glass, 1-L minimum, with screw cap.
6.1.2 Solid samples (soil, sediment, sludge, filter cake, compost, and similar
materials that contain more than 5 percent solids) - Sample bottle, wide-mouth,
amber glass, 500-mL minimum.
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Method 1698 December 2007
6.1.3 If amber bottles are not available, samples must be protected from light.
6.1.4 Bottle caps-Threaded to fit sample bottles. Caps must be lined with
fluoropolymer.
6.1.5 Cleaning - Bottles are washed with detergent and water, then solvent rinsed
before use. Liners are washed with detergent and water and rinsed with reagent
water before use.
6.2 Equipment for glassware cleaning
6.2.1 Laboratory sink with overhead fume hood
6.2.2 Kiln capable of reaching 450 °C within 2 hours and maintaining 450 - 500 EC
within V10 EC, with temperature controller and safety switch (Cress
Manufacturing Co, Santa Fe Springs, CA, B31H, X3 ITS, or equivalent). See the
precautions in Section 4.2.3.
6.3 Compositing equipment - Automatic or manual compositing system incorporating glass
containers cleaned per bottle cleaning procedure above. Only glass or fluoropolymer
tubing must be used. If the sampler uses a peristaltic pump, a minimum length of
compressible silicone rubber tubing may be used in the pump only. Before use, the tubing
must be thoroughly rinsed with methanol, followed by repeated rinsing with reagent water
to minimize sample contamination. An integrating flow meter is used to collect
proportional composite samples.
6.4 Equipment for sample preparation
6.4.1 Laboratory fume hood of sufficient size to contain the sample preparation
equipment listed below.
6.4.2 Glove box (optional)
6.4.3 Tissue homogenizer - VirTis Model 45 Macro homogenizer (American Scientific
Products H-3515, or equivalent) with stainless steel Macro-shaft and Turbo-shear
blade.
6.4.4 Vortex mixer
6.4.5 Ultrasonic mixer
6.4.6 Oven - Capable of maintaining a temperature of 110V5 °C
6.4.7 Dessicator
6.4.8 Analytical balance - Capable of weighing 0.1 mg
6.4.9 Top loading balance - Capable of weighing 10 mg
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Method 1698 December 2007
6.5 Apparatus for measuring pH
6.5.1 pH meter, with combination glass electrode
6.5.2 pH paper, wide range (Hydrion Papers, or equivalent)
6.6 Aqueous sample extraction apparatus
6.6.1 Graduated cylinder, 1-L capacity
6.6.2 Separatory runnels, 250-, 500-, 1000- and 2000-mL, with fluoropolymer
stopcocks
6.6.3 Continuous liquid/liquid extraction (CLLE) - Fluoropolymer or glass connecting
joints and stopcocks without lubrication, 1.5-2 L capacity (Hershberg-Wolf
Extractor, Cal-Glass, Costa Mesa, California, 1000 mL or 2000 mL, or
equivalent). CLLE is an option and is not required in separatory funnel
procedures are used.
6.7 Solid sample extraction apparatus
6.7.1 Soxhlet extractor - 50-mm ID, 200-mL capacity with 500-mL flask (Cal-Glass
LG-6900, or equivalent, except substitute 500-mL round-bottom flask for
300-mL flat-bottom flask)
6.7.2 Thimble - 43 H 123 to fit Soxhlet (Cal-Glass LG-6901-122, or equivalent)
6.7.3 Heating mantle - Hemispherical, to fit 500-mL round-bottom flask (Cal-Glass
LG-8801-112, or equivalent)
6.7.4 Variable transformer-Powerstat (or equivalent), 110-volt, 10-amp
6.8 Beakers and Erlenmeyer flasks - 250-, 400-, 500-, and 1000-mL
6.9 Spatulas - Stainless steel
6.10 Filtration apparatus
6.10.1 Pyrex glass wool - Solvent-extracted using a Soxhlet extractor for 3 hours
minimum
6.10.2 Glass funnel - 125- to 250-mL
6.10.3 Glass-fiber filter paper - Whatman GF/D (or equivalent), to fit glass funnel in
Section 6.10.2.
6.11 Centrifuge - Capable of rotating 500-mL centrifuge bottles or 50-mL centrifuge tubes at
5,000 rpm minimum, equipped with 500-mL centrifuge bottles with screw-caps, and 50-mL
centrifuge tubes with screw-caps, to fit centrifuge. Bottles and tubes may be glass or
plastic.
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Method 1698 December 2007
6.12 Pipet apparatus and pipets
6.12.1 Pipetter - variable volume
6.12.2 Pipet tips - disposable polypropylene, sizes from 1 - 10 joL to 5 mL
6.12.3 Disposable - Pasteur, 150-mm long x 5-mm ID (Fisher Scientific 13-678-6A, or
equivalent)
6.12.4 Disposable - Serological, 50-mL (8- to 10- mm ID)
6.13 Chromatographic column - 1 cm x 25 cm with 100- or 250- mL reservoir
6.14 Rotary evaporator - Buchi/Brinkman-American Scientific No. E5045-10, or equivalent,
equipped with a variable temperature water bath and a vacuum source with shutoff valve at
the evaporator and vacuum gauge. A recirculating water pump and chiller are
recommended, as use of tap water for cooling the evaporator wastes large volumes of water
and can lead to inconsistent performance as water temperatures and pressures vary.
6.14.1 Round-bottom flask - 100-mL and 500-mL or larger, with ground-glass fitting
compatible with the rotary evaporator
6.14.2 Boiling chips
6.14.2.1 Glass or silicon carbide - Approximately 10/40 mesh, extracted
with methylene chloride and baked at 450 EC for one hour
minimum
6.14.2.1 Fluoropolymer (optional) - Extracted with methylene chloride
6.15 Nitrogen evaporation apparatus - Equipped with water bath controlled in the range of 30 -
60 EC (N-Evap, Organomation Associates, Inc., South Berlin, MA, or equivalent), installed
in a fume hood.
6.16 Amber glass vials - 2- to 5-mL with fluoropolymer-lined screw-cap
6.17 GC autosampler vials - Glass, 0.8- to 2.0- mL, conical, with fluoropolymer-lined screw
or crimp cap
6.18 Gas chromatograph - Must have splitless or on-column injection port for capillary
column, temperature program with isothermal holds, and must meet all of the
performance specifications in Section 10.
6.18.1 GC column - 30 V 5-m long x 0.25 V 0.02-mm ID; 0.25-^im film (Restek RTx-5,
or equivalent)
6.18.2 The GC column must resolve coprostanol and epicoprostanol to a valley height
less than 20 percent of the shorter of the two peaks.
6.18.3 Alternative columns have not been tested and therefore are not permitted except as
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Method 1698 December 2007
noted above. In a future version of this method EPA may provide criteria for determining
equivalency of alternative columns.
6.19 Mass spectrometer - 28- to 40-eV electron impact ionization, must be capable of
selectively monitoring a minimum of 22 exact m/zs at high resolution (35,000) during a
period less than 1.5 seconds, and must meet all of the performance specifications in
Section 10.
6.20 GC/MS interface - The mass spectrometer (MS) must be interfaced to the GC such that
the end of the capillary column terminates within 1 cm of the ion source but does not
intercept the electron or ion beams.
6.21 Data system - Capable of collecting, recording, storing, and processing MS data
6.21.1 Data acquisition - The signal at each exact m/z must be collected repetitively
throughout the monitoring period and stored on a mass storage device.
6.21.2 Response factors and multipoint calibrations - The data system must record and
maintain lists of response factors (response ratios for isotope dilution) and
multipoint calibrations. Computations of relative standard deviation (RSD) are
used to test calibration linearity. Statistics on initial (Section 9.4) and ongoing
(Section 15.5.4) performance should be computed and maintained, either on the
instrument data system, or on a separate computer system.
7.0 Reagents and Standards
Note: All reagents are ACS Reagent Grade unless specified otherwise.
7.1 pH adjustment and stabilization solutions
7.1.1 Potassium hydroxide - Dissolve 20 g reagent grade KOH in 100 mL reagent water.
7.1.2 Sulfuric acid - Reagent grade (specific gravity 1.84)
7.1.3 Hydrochloric acid - Reagent grade, 6N
7.1.4 Sodium chloride - Reagent grade, prepare at 5% (w/v) solution in reagent water
7.2 Sodium sulfate
7.2.1 Used for solution drying - Sodium sulfate, reagent grade, granular, anhydrous
(Baker 3375, or equivalent), rinsed with methylene chloride (20 mL/g), baked at
400 EC for 1 hour minimum, cooled in a dessicator, and stored in a pre-cleaned
glass bottle with screw-cap that prevents moisture from entering. If, after
heating, the sodium sulfate develops a noticeable grayish cast (due to the
presence of carbon in the crystal matrix), that batch of reagent is not suitable for
use and should be discarded. Extraction with methylene chloride (as opposed to
simple rinsing) and baking at a lower temperature may produce sodium sulfate
that is suitable for use.
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Method 1698 December 2007
7.2.2 Used as a drying agent when extracting solids and biosolids - Sodium sulfate,
reagent grade, powdered, treated and stored as in Section 7.2.1.
7.3 Prepurified nitrogen
7.4 Solvents - Acetone, toluene, hexane, pyridine, methanol, and methylene chloride,
distilled in glass, pesticide quality, lot-certified to be free of interferences.
7.5 White quartz sand - For use in Soxhlet extraction, 60/70 mesh (Aldrich Chemical, Cat.
No. 27-437-9, or equivalent). Bake at 450 EC for 4 hours minimum.
7.6 Cleanup reagents
7.6.1 Alumina - Basic, Brockman Activity 1, 60-325 mesh (Fisher, or equivalent), 5%
deactivated. Heat for a minimum of 8 hours at 450°C, cool, deactivate to 5%
water (w/w), and store under dry nitrogen or in a bottle that will prevent moisture
from entering.
7.6.2 Florisil - Pesticide grade, 60-100 mesh (Supelco or U.S. Silica, equivalent).
Heat for a minimum of 8 hours at 450°C, cool, deactivate to 5% water (w/w), and
store under dry nitrogen or in a bottle that will prevent moisture from entering.
7.6.3 Copper foil or powder - For sulfur removal. Fisher, Alfa Aesar, or equivalent.
Copper foil is cut into approximately 1-cm squares. Copper must be activated on
each day it will be used, as described below.
7.6.3.1 Place the quantity of copper needed for sulfur removal in a ground-
glass stoppered Erlenmeyer flask or bottle. Cover the foil or powder
with methanol.
7.6.3.2 Add HC1 dropwise (0.5 - 1.0 mL) while swirling, until the copper
brightens.
7.6.3.3 Pour off the methanol/HCl and rinse 3 times with acetone, then 3 times
with hexane.
7.6.3.4 For the copper foil, cover with hexane after the final rinse. Store in a
stoppered flask under nitrogen until used. For the powder, dry on a
rotary evaporator. Store in a stoppered flask under nitrogen until used.
7.7 Derivatization reagent - jV,O-bis(Trimethylsilyl)trifluoroacetamide with
trimethylchlorosilane (BSTFA: TMCS; 99:1), Supelco, or equivalent, used as received.
7.8 Reference matrices - Matrices such as reagent water or sand in which the steroids and
hormones and interfering compounds are not detected by this method.
7.8.1 Reagent water - Bottled water purchased locally, or prepared by passage through
activated carbon.
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Method 1698 December 2007
7.8.2 High-solids reference matrix - Playground sand or similar material. Prepared by
extraction with methylene chloride and/or baking at 450 EC for a minimum of 4
hours.
7.8.3 Other reference matrices of interest may be used if the results from the tests given
in Section 9.2 demonstrate acceptable performance. Ideally, the matrix should be
free of the analytes of interest, but in no case must the background level of the
analytes in the reference matrix exceed the minimum levels in Table 2. If low
background levels of the analytes of interest are present in the reference matrix, the
spike level of the analytes used in Section 9.2 should be increased to provide a
spike-to-background ratio of approximately 5 (Reference 6).
7.9 Standard solutions - Prepare from materials of known purity and composition or
purchase as solutions or mixtures with certification to their purity, concentration, and
authenticity. If the chemical purity is 98 % or greater, the weight may be used without
correction to calculate the concentration of the standard. Observe the safety precautions
in Section 5 and the recommendation in Section 5.1.2.
7.9.1 For preparation of stock solutions from neat materials, dissolve an appropriate
amount of assayed reference material in solvent. For example, weigh 10 - 20 mg
of testosterone to three significant figures in a 10-mL ground-glass-stoppered
volumetric flask and fill to the mark with methanol (dichloromethane or acetone
may also be used). After the compound is completely dissolved, transfer the
solution to a clean 15-mL vial with fluoropolymer-lined cap.
7.9.2 When not being used, store standard solutions in the dark at room temperature, or
frozen, in screw-capped vials with fluoropolymer-lined caps, or under a non-
reactive gas (e.g., nitrogen) in flame-sealed ampules. Place a mark on the vial at
the level of the solution so that solvent loss by evaporation can be detected.
Replace the solution if solvent loss has occurred.
7.10 Native (unlabeled) stock solution
7.10.1 Native stock solution - Prepare to contain the steroids and hormones at the
concentrations shown in Table 3, or purchase prepared solutions. If additional
analytes are to be determined, include the additional native compounds in this
stock solution.
7.10.2 Stock solutions should be checked for signs of degradation prior to the
preparation of calibration or performance test standards. A stock solution may be
checked for degradation by diluting and analyzing the solution using this method
and comparing the result to freshly prepared standards prepared previously
and/or to a QC Check Sample obtained from a different source (Section 7.16).
7.11 Labeled compound stock solution (Table 3)
Note: Stock and working labeled compound solutions prepared in methanol should be stored no
more than two months, as analytes such as norethindrone-d6, norgesterol-d6, and
progesterone-d9 contain deuterium atoms beta to carbonyl groups that are labile. These
deuterium atoms may undergo proton exchange in a protinated solvents.
12
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Method 1698 December 2007
7.11.1 Labeled steroid/hormone stock solution - Prepare in methanol at the
concentrations in Table 3 or purchase prepared standards. If additional
compounds are to be determined by isotope dilution, include the additional
labeled compounds in this stock solution.
7.11.2 Labeled cholesterol stock solution - Prepare in methanol at the concentration in
Table 3, or purchase a prepared standard.
7.11.3 Labeled injection internal standard stock solution - Prepare pyrene-d10 in hexane
at the concentration in Table 3, or purchase a prepared standard. This solution is
added to each concentrated extract prior to injection into the HRGC/HRMS. The
stock solution is used without dilution. When 50 |oL of this solution are spiked
into a 500-|oL extract, or when 2 \\L are spiked into a 20 \\L extract, the
concentration of pyrene-dio will be 250 ng/mL (pg/joL), as shown in Table 3.
7.12 Calibration standards - Combine and dilute the solutions in Sections 7.10 and 7.11 to
produce the calibration solutions in Table 4 or purchase prepared standards for the CS-0.2
to CS-5 set of calibration solutions. These solutions permit the relative response (native
to labeled) and response factor to be measured as a function of concentration. The CS-3
standard is used for calibration verification (VER). The calibration standards must be
derivatized for use (Section 13.3).
7.13 Native standard spiking solution - Used for determining initial precision and recovery
(IPR; Section 9.2) and ongoing precision and recovery (OPR; Section 15.5). Dilute the
native stock solution (Section 7.10.1) with methanol to produce the concentrations of the
steroids/hormones shown in Table 3. When 1 mL of this solution is spiked into an IPR
(Section 9.2.1) or OPR (Section 15.5) and extracted, and the extract is concentrated to
500 |oL; or when 40 \\L is spiked into an IPR or OPR and extracted, and the extract is
concentrated to 20 (iL, the concentration of the analytes in the final volume will be as
shown in the last column in Table 3. Prepare only the amount necessary for each
reference matrix with each sample batch.
7.14 Labeled standard spiking solution - This solution is spiked into each sample (Section 9.3)
and into the IPR (Section 9.2.1), OPR (Section 15.5), and blank (Section 9.5) to measure
recovery. Dilute the labeled steroid/hormone stock solution (Section 7.11.1) with
methanol to produce the concentrations of the labeled compounds shown in Table 3.
When 1 mL of this solution is spiked into an IPR, OPR, blank, or sample and extracted,
and the extract is concentrated to 500 |o,L; or when 40 (iL is spiked into an IPR, OPR,
blank or sample and extracted, and the extract is concentrated to 20 (iL, the concentration
in the final volume will be as shown in the last column Table 3. Prepare only the amount
necessary for each reference matrix with each sample batch.
7.15 Labeled cholesterol spiking solution - This solution is added to a sample when a high
concentration of cholesterol is known or expected to be present. Dilute the labeled
cholesterol stock solution (Section 7.11.2) with methanol to produce the spiking solution
concentration shown in Table 3. When 1 mL of this solution is spiked into a sample
along with the labeled standard spiking solution, derivatized, and concentrated to a final
extract volume of 500 |oL, the concentration in the final volume will be 125 (ig/mL
(125,000 ng/mL) (see Table 3). Prepare only the amount necessary for the number of
13
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Method 1698 December 2007
samples in the sample batch. It is not necessary to spike this solution into the IPR, OPR,
and blank.
7.16 QC check sample - A QC Check Sample should be obtained from a source independent
of the calibration standards. Ideally, this check sample would be a Standard Reference
Material (SRM) from the National Institute of Standards and Technology (NIST)
containing the compounds of interest in known concentrations in a sample matrix similar
to the matrix of interest. If no SRM is available, a certified reference material (CRM)
may be used or a QC check sample may be prepared from materials from a source or lot
of standards separate from those used for calibration and spiked into a clean reference
matrix.
7.17 Stability of solutions - Standard solutions used for quantitative purposes (Sections 7.10 -
7.15) should be assayed periodically (e.g., every 6 months) against SRMs from NIST
(where available), or certified reference materials from a source that will attest to the
authenticity and concentration, to assure that the composition and concentrations have not
changed.
8.0 Sample Collection, Preservation, and Storage
8.1 Collect samples in plastic or amber glass containers following conventional sampling
practices designed to obtain a sample that is representative of the material of interest
(Reference 7).
8.2 Aqueous samples
8.2.1 Samples of wastewater effluents, drinking water, ambient water, or groundwater
that flow freely are collected as grab samples or in refrigerated bottles using
automatic sampling equipment. Collect 1 L. If high concentrations of the
steroids/hormones are expected, collect a smaller volume (e.g., 100 mL) in
addition to the 1-L sample. Do not rinse the bottle with sample before collection.
8.2.2 When sampling influents to treatment, in-process waste streams, and liquid
sample types other than wastewater effluents, drinking water, ambient water, or
groundwater, it may be necessary to collect two 1-L aliquots of each sample to
provide enough material for separate analyses of the aqueous and solid phases.
8.2.3 If residual chlorine is present, add 80 mg sodium thiosulfate per liter of water.
Any method suitable for field use maybe employed to test for residual chlorine.
8.2.4 Maintain aqueous samples in the dark at <6 EC from the time of collection until
receipt at the laboratory (see 40 CFR 136.6(e), Table II).
8.2.5 Alternatively, samples maybe stored frozen from time of receipt at the laboratory
until analysis. If the samples will be frozen, collect the 1-L samples in larger
containers (>1.1 L) to allow room for expansion, or collect multiple aliquots in
smaller containers that are not filled completely (e.g., three 500-mL containers
not filled completely).
14
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Method 1698 December 2007
8.3 Solid, mixed-phase, and semi-solid samples
8.3.1 Collect samples as grab samples using wide-mouth jars. Collect a sufficient
amount of wet material to provide a minimum of 20 g of solids.
8.3.2 Maintain solid, semi-solid, biosolids, and mixed-phase samples in the dark at
<6EC from the time of collection until receipt at the laboratory.
8.3.3 Once received at the laboratory, store solid, semi-solid, and mixed-phase samples
in the dark at less than -10 EC.
8.4 Biosolids samples
Biosolids are the residual from various wastewater treatment processes and, as such, may
be produced and managed in many forms, ranging from pourable liquids containing less
than 1% solids, through viscous solids thickened with polymers, to dry caked solids with
little or no moisture. Sample collection procedures for biosolids require knowledge of
the form of the material at the specific site.
8.4.1 For biosolids that are pourable liquids, collect 1-L grab samples in wide-mouth
glass containers from taps, valves, or biosolids storage tanks.
8.4.2 Sampling biosolids produced and transferred by continuous processes such as
belt presses or centrifuges involves collecting multiple small grab samples,
homogenizing those grabs in a clean stainless steel container, and transferring an
aliquot of the homogenized bulk sample to a wide-mouth glass container. The
final sample aliquot should contain at least 20 g of dry solids, and larger
volumes, up to 1-L, may be collected.
8.4.3 Biosolids in drying beds, compost piles, and other biosolids management
processes involves collecting multiple grabs from different areas of the bed, pile,
etc. Remove sticks, leaves, large wood chips, and other obvious plant materials
used in composting and homogenize the grab samples in a clean stainless steel
container. Transfer an aliquot of the homogenized bulk sample to a wide-mouth
glass container. The final sample aliquot should contain at least 20 g of dry
solids, and larger volumes, up to 1-L, may be collected.
8.4.4 Maintain biosolids samples in the dark at <6EC from the time of collection until
receipt at the laboratory.
8.4.5 Once received at the laboratory, store all biosolids samples in the dark at less
than -10 EC.
8.5 Holding times
EPA has not conducted formal holding time studies for these analytes to date. Use the
information below as guidance. Exceeding these default holding times does not invalidate
the sample results.
15
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Method 1698 December 2007
8.5.1 Aqueous samples - Anecdotal evidence suggests that some may degrade rapidly in
aqueous samples. Therefore, begin sample extraction within 7 days of collection
(within 48 hours is strongly encouraged). Extracts should be analyzed within 40
days of extraction. Freezing of aqueous samples is encouraged to minimize
degradation, in which case, samples should be extracted within 48 hours of
removal from the freezer.
8.5.2 Biosolid, solid, mixed-phase, and semi-solid samples - Anecdotal evidence
suggests that some may degrade rapidly in these samples. Therefore, begin sample
extraction within 7 days of collection (within 48 hours is strongly encouraged).
Extracts should be analyzed within 40 days of extraction. Freezing of biosolids,
mixed phase and semisolid samples is encouraged to minimize degradation, in
which case, samples should be extracted within 48 hours of removal from the
freezer.
8.5.3 If extraction within 48 hours is not practical, samples should be frozen to increase
the holding time to seven days.
8.5.4 If the sample will not be extracted within 48 hours of collection, the laboratory
should adjust the pH of aqueous samples to 5.0 to 9.0 with sodium hydroxide or
sulfuric acid solution. Record the volume of acid or base used.
8.4 Store sample extracts in the dark at less than -10 °C until analyzed. Analyze extracts
within 40 days of extraction.
9.0 Quality Control
9.1 Each laboratory that uses this method is required to operate a formal quality assurance
program (Reference 9). The minimum requirements of this program consist of an initial
demonstration of laboratory capability, analysis of samples spiked with labeled
compounds to evaluate and document data quality, and analysis of standards and blanks
as tests of continued performance. Laboratory performance is compared to established
performance criteria to determine if the results of analyses meet the performance
characteristics of the method.
If the method is to be applied to sample matrix other than water (e.g., soils, filter cake,
compost) the most appropriate alternative reference matrix (Sections 7.8.2, 7.8.3 and
7.16) is substituted for the reagent water matrix (Section 7.8.1) in all performance tests.
9.1.1 The laboratory must make an initial demonstration of the ability to generate
acceptable precision and recovery with this method. This demonstration is given
in Section 9.2.
9.1.2 In recognition of advances that are occurring in analytical technology, and to
overcome matrix interferences, the laboratory is permitted certain options to
improve separations or lower the costs of measurements. These options include
alternative extraction, concentration, and cleanup procedures, and changes in
columns and detectors (see also 40 CFR 136.6). Alternative determinative
techniques, such as the substitution of spectroscopic or immunoassay techniques,
and changes that degrade method performance, are not allowed. If an analytical
16
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Method 1698 December 2007
technique other than the techniques specified in this method is used, that
technique must have a specificity equal to or greater than the specificity of the
techniques in this method for the analytes measured in this method.
9.1.2.1 Each time a modification is made to this method, the laboratory is
required to repeat the procedure in Section 9.2. If the detection limit of
the method will be affected by the change, the laboratory is required to
demonstrate that the MDLs (40 CFR Part 136, Appendix B) are lower
than one-third the regulatory compliance level or the MDLs in this
method, whichever are greater. If calibration will be affected by the
change, the instrument must be recalibrated per Section 10. Once the
modification is demonstrated to produce results equivalent or superior
to results produced by this method as written, that modification may be
used routinely thereafter, so long as the other requirements in this
method are met (e.g., labeled compound recovery).
9.1.2.2 The laboratory is required to maintain records of modifications made
to this method. These records include the following, at a minimum:
9.1.2.2.1 The names, titles, addresses, and telephone numbers of the
analyst(s) that performed the analyses and modification,
and of the quality control officer that witnessed and will
verify the analyses and modifications
9.1.2.2.2 A listing of pollutant(s) measured, by name and CAS
Registry number.
9.1.2.2.3 A narrative stating reason(s) for the modifications.
9.1.2.2.4 Results from all quality control (QC) tests comparing the
modified method to this method, including:
a) Calibration (Section 10).
b) Calibration verification (Section 15.3).
c) Initial precision and recovery (Section 9.2).
d) Labeled compound recovery (Section 9.3).
e) Analysis of blanks (Section 9.5).
f) Accuracy assessment (Section 9.4).
9.1.2.2.5 Data that will allow an independent reviewer to validate
each determination by tracing the instrument output (peak
height, area, or other signal) to the final result. These data
are to include:
a) Sample numbers and other identifiers.
b) Extraction dates.
c) Analysis dates and times.
d) Analysis sequence/run chronology.
e) Sample weight or volume (Section 11).
17
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Method 1698 December 2007
f) Extract volume prior to each cleanup step (Section
13).
g) Extract volume after each cleanup step (Section 13).
h) Final extract volume prior to injection (Section 14).
i) Injection volume (Sections 10.3 and 14.3).
j) Dilution data, differentiating between dilution of a
sample or extract (Section 17.5.1).
k) Instrument and operating conditions.
1) Column (dimensions, liquid phase, solid support,
film thickness, etc).
m) Operating conditions (temperatures, temperature
program, flow rates).
n) Detector (type, operating conditions, etc).
o) Chromatograms, printer tapes, and other recordings
of raw data.
p) Quantitation reports, data system outputs, and other
data to link the raw data to the results reported.
9.1.3 Analyses of method blanks are required to demonstrate freedom from
contamination (Section 4.3). The procedures and criteria for analysis of a
method blank are given in Sections 9.5 and 15.6.
9.1.4 The laboratory must spike all samples with labeled compounds to monitor
method performance. This test is described in Section 9.3. When results of these
spikes indicate atypical method performance for samples, the samples are diluted
to bring method performance within acceptable limits. Procedures for dilution
are given in Section 17.5.
9.1.5 The laboratory must, on an ongoing basis, demonstrate through calibration
verification and the analysis of the ongoing precision and recovery standard
(OPR) and blanks that the analytical system is in control. These procedures are
given in Sections 15.1 through 15.6.
9.1.6 The laboratory should maintain records to define the quality of data generated.
Development of accuracy statements is described in Section 9.4.
9.2 Initial precision and recovery (IPR)-To establish the ability to generate acceptable
precision and recovery, the laboratory must perform the following operations.
9.2.1 For low solids (aqueous) samples, extract, concentrate, and analyze four 1-L
aliquots of reagent water spiked with 1 mL each of the Native standard spiking
solution (Section 7.13) and the labeled standard spiking solution (Section 7.14),
according to the procedures in Sections 11 through 18. For an alternative sample
matrix, four aliquots of the alternative reference matrix (Section 7.8) are used.
All sample processing steps that are to be used for processing samples, including
preparation (Section 11), extraction (Section 12), and cleanup (Section 13), must
be included in this test.
9.2.2 Using results of the set of four analyses, compute the average percent recovery
(X) of the extracts and the relative standard deviation (RSD) of the concentration
18
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Method 1698 December 2007
for each compound, by isotope dilution for steroids/hormones with a labeled
analog, and by internal standard for steroids/hormones without a labeled analog
and for the labeled compounds.
9.2.3 For each native analyte and labeled compound, compare RSD and X with the
corresponding limits for initial precision and recovery in Table 5. If RSD and X
for all compounds meet the acceptance criteria, system performance is acceptable
and analysis of blanks and samples may begin. If, however, any individual RSD
exceeds the precision limit or any individual X falls outside the range for
recovery, system performance is unacceptable for that compound. Correct the
problem and repeat the test (Section 9.2).
9.3 To assess method performance on the sample matrix, the laboratory must spike all
samples with the labeled standard spiking solution (Section 7.14).
9.3.1 Analyze each sample according to the procedures in Sections 11 through 18.
9.3.2 Compute the percent recovery of the labeled compounds using the internal
standard method (Section 17.2).
9.3.3 The recovery of each labeled compound must be within the limits in Table 5. If
the recovery of any compound falls outside of these limits, method performance
is unacceptable for that compound in that sample. Additional cleanup procedures
must then be employed to attempt to bring the recovery within the normal range.
If the recovery cannot be brought within the normal range after all cleanup
procedures have been employed, water samples are diluted and smaller amounts
of soils, sludges, sediments, and other matrices are analyzed per Section 18.
9.4 Recoveries of labeled compounds from samples should be assessed and records
maintained.
9.4.1 After the analysis of 30 samples of agiven matrix type (water, soil, sludge, etc.)
for which the labeled compounds pass the tests in Section 9.3, compute the
average percent recovery (R) and the standard deviation of the percent recovery
(SR) for the labeled compounds only. Express the assessment as a percent
recovery interval from R ! 2SR to R + 2SR for each matrix. For example, if R =
90% and SR = 10% for 30 analyses of biosolids, the recovery interval is
expressed as 70 to 110%.
9.4.2 Update the accuracy assessment for each labeled compound in each matrix on a
regular basis (e.g., after each five to ten new measurements).
9.5 Method blanks - A reference matrix method blank is analyzed with each sample batch
(Section 4.3) to demonstrate freedom from contamination. The matrix for the method
blank must be similar to the sample matrix for the batch, e.g., a 1-L reagent water blank
(Section 7.8.1), high-solids reference matrix blank (Section 7.8.2), or alternative
reference matrix blank (Section 7.8.3).
9.5.1 Spike 1.0 mL each of the labeled standard spiking solution (Section 7.14) into the
method blank, according to the procedures in Sections 11 through 18. Prepare,
19
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Method 1698
December 2007
9.6
9.7
9.8
extract, clean up, and concentrate the method blank. Analyze the blank
immediately after analysis of the OPR (Section 15.6) to demonstrate freedom
from contamination.
9.5.2 If any steroid or hormone (Table 1) is found in the blank at greater than the
minimum level (Table 2) or one-third the regulatory compliance limit, whichever
is greater; or if any potentially interfering compound is found in the blank at the
minimum level for each native analyte in Table 2 (assuming a response factor of
1 relative to the quantitation reference in Table 2 for a potentially interfering
compound; i.e., a compound not listed in this method), analysis of samples must
be halted until the sample batch is re-extracted and the extracts re-analyzed, and
the blank associated with the sample batch shows no evidence of contamination
at these levels. All samples must be associated with an uncontaminated method
blank before the results for those samples may be reported or used for permitting
or regulatory compliance purposes.
QC Check Sample - Analyze the QC Check Sample (Section 7.16) periodically to assure
the accuracy of calibration standards and the overall reliability of the analytical process.
It is suggested that the QC Check Sample be analyzed at least quarterly.
The specifications contained in this method can be met if the apparatus used is calibrated
properly and then maintained in a calibrated state. The standards used for calibration
(Section 10), calibration verification (Section 15.3), and for initial (Section 9.2) and
ongoing (Section 15.5) precision and recovery should be identical, so that the most
precise results will be obtained. A GC/HRMS instrument will provide the most
reproducible results if dedicated to the settings and conditions required for determination
of steroids and hormones by this method.
Depending on specific program requirements, field replicates may be collected to
determine the precision of the sampling technique, and spiked samples may be required
to determine the accuracy of the analysis when the internal standard method is used.
10.0 Calibration and Standardization
10.1 Establish the operating conditions necessary to meet the retention times (RTs) and
relative retention times (RRTs) for the steroids and hormones in Table 2. The GC
conditions may be optimized for compound separation and sensitivity.
10.1.1 Suggested operating conditions
Suggested GC Conditions
Injector Type
Carrier Gas
Injector Temperature (°C)
Maximum Temperature (°C)
Split/Splitless
Helium, variable
280
325
20
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Method 1698
December 2007
Suggested GC Temperature Program
Initial temperature (°C)
Hold time (min)
First Temperature Ramp (°C min"1)
Hold Temperature (°C)
Hold time (min)
Second Temperature Ramp (°C min"1)
Hold Temperature (°C)
Hold time (min)
Third Temperature Ramp (°C min"1)
Final Temperature (°C)
Hold time (min)
100
4
10
265
7
10
300
4
20
310
3
Suggested MS Conditions
Source temperature (°C)
Electron energy (eV)
Detector voltage (V)
Scan time (s)
280
35
Variable
<1.5
Note: A shorter scan time gives more points and may improve peak definition and integration
accuracy. However a faster scan reduces channel integration time and results in a slight
decrease in sensitivity. The 1.5-second scan time is an upper limit and shorter scan times
are recommended. Using the GC column specified in Sec. 6.18.1 (3Q 5-m long x 0.25
0.02-mm ID; 0.25-|o,m film (Restek RTX-5, or equivalent)) and the GC program above,
EPA found that a 1.5-second scan time provided sufficient points to define and accurately
integrate peaks. The typical peak width at the base for these compounds, under these
conditions, was between 9 and 24 seconds (with a mean of 12.7), with a minimum of 9
scans (data points) across each peak.
10.1.1.1 All portions of the column that connect the GC to the ion source should
remain at or above the interface temperature during analysis to pre-
clude condensation of less volatile compounds.
10.1.1.2 The GC conditions may be optimized for compound separation and
sensitivity. Once optimized, the same GC conditions must be used for
the analysis of all standards, blanks, IPR and OPR standards, and
samples.
10.1.2 Retention time calibration for the native and labeled compounds
10.1.2.1 Inject the CS-3 calibration standard (Section 7.12 and Table 4).
Establish the beginning and ending retention times for the scan
descriptors (functions) in Table 2. Scan functions other than those
listed in Table 2 may be used provided the MLs in Table 2 are met.
Store the retention time (RT) and relative retention time (RRT) for
each compound in the data system.
10.1.2.2 The absolute retention time of last-eluted compound must be equal to or
greater than its retention time in Table 2; otherwise, the GC operating
conditions must be adjusted and this test repeated until this minimum
retention time criterion is met.
21
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Method 1698 December 2007
10.1.2.3 If a column alternate to the column suggested in Section 6.18.1 is used, a
similar minimum retention time specification (Section 10.1.2.2) must be
established for the alternate column so that interferences that may be
encountered in environmental samples will be resolved from the analytes
of interest. This specification is deemed to be met if the retention time
of the last-eluted compound is equal to or greater than its retention time
in Table 2.
10.2 Mass spectrometer (MS) resolution
10.2.1 Using PFK (or other reference substance) and a molecular leak, tune the
instrument to meet the minimum required resolving power of 5,000 (10% valley)
at m/z 280.9825, or other significant PFK fragment in the range of 250 - 300.
For each function (Table 2), monitor and record the resolution and exact m/zs of
three to five reference peaks covering the mass range of the function. The level
of PFK (or other reference substance) metered into the HRMS during analyses
should be adjusted so that the amplitude of the most intense selected lock-mass
m/z signal (regardless of the function/descriptor number - see Table 2 for
functions) does not exceed 10% of the full-scale deflection for a given set of
detector parameters. Under those conditions, sensitivity changes that might
occur during the analysis can be more effectively monitored.
Note: Different lots and types of PFK can contain varying levels of
contamination, and excessive PFK (or other reference substance) may
cause noise problems and contamination of the ion source necessitating
increased frequency of source cleaning.
10.2.2 The analysis time for the analytes may exceed the long-term mass stability of the
mass spectrometer. Because the instrument is operated in the high-resolution
mode, mass drifts of a few ppm (e.g., 5 ppm in mass) can have serious adverse
effects on instrument performance. Therefore, mass-drift correction is
mandatory and a lock-mass m/z from perfluorokerosene (PFK) or other reference
substance is used for drift correction. The lock-mass m/z is dependent on the
exact m/zs monitored within each descriptor. The deviation between each
monitored exact m/z and the theoretical m/z must be less than 5 ppm.
10.2.3 Obtain a selected ion current profile (SICP) at the two exact m/zs specified in
Table 2 and at 35,000 resolving power for each native and labeled compound.
Because of the extensive mass range covered in each function, it may not be
possible to maintain 5,000 resolution throughout the mass range during the
function. Therefore, resolution must be 33,000 throughout the mass range and
must be 35,000 in the center of the mass range for each function.
10.2.4 If the HRMS has the capability to monitor resolution during the analysis, it is
acceptable to terminate the analysis when the resolution falls below the minimum
(Section 10.2.1 and 10.2.3) to save re-analysis time.
10.3 Ion abundance ratios, minimum levels, and signal-to-noise ratios during calibration
22
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Method 1698 December 2007
Choose an injection volume of either 1 or 2 jaL, consistent with the capability of the
GC/HRMS instrument. Inject a 1- or 2-|oL aliquot of the CS-0.2 or CS-1 calibration
solution (Table 4) using the GC conditions in Section 10.1.1. The CS-0.2 solution is used
for modern high-sensitivity HRMS instruments; the CS-1 solution is used for older, less-
sensitive instruments.
10.3.1 Measure the SICP areas for each compound, and compute the ion abundance
ratios at the exact m/zs specified in Table 2. Compare the computed ratio to the
theoretical ratio given in Table 2.
10.3.1.1 The exact m/zs to be monitored in each function/descriptor are
shown in Table 2. Each group or descriptor must be monitored in
succession as a function of GC retention time to ensure that the
steroids/hormones are detected. Additional m/zs may be monitored
in each descriptor, and the m/zs may be divided among more than the
descriptors listed in Table 2, provided that the laboratory is able to
monitor the m/zs of all steroids/hormones that may elute from the
GC in a given RT window.
10.3.1.2 The mass spectrometer must be operated in a mass-drift correction
mode, using PFK (or other reference substance) to provide lock
m/zs. Each lock mass must be monitored and must not vary by more
than V 20% throughout its respective retention time window. Varia-
tions of lock mass by more than 20% indicate the presence of co-
eluting interferences that raise the source pressure and may
significantly reduce the sensitivity of the mass spectrometer. Re-
injection of another aliquot of the sample extract may not resolve the
problem and additional cleanup of the extract may be required to
remove the interference. A lock mass interference or suppression in
a retention time region in which the steroids/hormones and labeled
compounds do not elute may be ignored.
10.3.2 The ion abundance ratios for all native and labeled compounds in the CS-0.2 or
CS-1 standard must be within ±30% of the ratios in Table 2, or in the most recent
calibration or calibration verification; otherwise, the mass spectrometer must be
adjusted and this test repeated until the m/z ratios fall within the limits specified.
If the adjustment alters the resolution of the mass spectrometer, resolution must
be verified (Section 10.2) prior to repeat of the test.
10.3.3 Verify that the HRGC/HRMS instrument meets the minimum levels (MLs) in
Table 2. The peaks representing the native and labeled compounds in the CS-0.2
or CS-1 calibration standard must have signal-to-noise ratios (S/N) 3 3;
otherwise, the mass spectrometer must be adjusted and this test repeated until the
minimum levels in Table 2 are met.
10.4 Calibration by isotope dilution
Isotope dilution is used for calibration of the native compounds for which a labeled
analog is available. The reference compound for each native compound is its labeled
analog, as listed in Table 2. A 6-point calibration (CS-0.2 to CS-5) is prepared for each
23
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Method 1698 December 2007
native compound when a high sensitivity HRMS is used (e.g., Waters Ultima).
Otherwise, a 5-point calibration is used.
10.4.1 For steroids/hormones determined by isotope dilution, the relative response (RR)
(labeled to native) vs. concentration in the calibration solutions (Table 4) is
computed over the calibration range according to the procedures described
below.
10.4.2 To calibrate the analytical system by isotope dilution, inject calibration standards
CS-0.2 through CS-5 (Section 7.12 and Table 4). Use a volume identical to the
volume chosen in Section 10.3, the procedure in Section 14, and the conditions in
Section 10.1.1.
10.4.3 Determine the relative response (RR) of each native compound to its labeled
analog using the area responses of both the primary and secondary exact m/zs
specified in Table 2 for each calibration standard. Use the labeled compounds
listed in Table 2 as the quantitation reference and the two exact m/zs listed in
Table 2 for quantitation. The areas at the two exact m/zs for the compound are
summed and divided by the summed area of the two exact m/zs for the
quantitation reference.
Note: Both exact m/zs are used as reference to reduce the effect of an
interference at a single m/z. Other quantitation references and
procedures may be used provided that the results produced are as
accurate as results produced by the quantitation references and
procedures described in this section.
10.4.4 Calibrate the native compounds with a labeled analog using the following
equation:
RR =
(Aln+A2n)C1
(Al1+A21)Cn
Where:
Aln and A2n = The areas of the primary and secondary m/zs for the native
compound
Ali and A2i = The areas of the primary and secondary m/zs for the labeled
compound.
Ci = The concentration of the labeled compound in the calibration
standard (Table 4).
Cn = The concentration of the native compound in the calibration
standard (Table 4).
10.4.5 Linearity - Store the relative response (RR) for each native compound at each
concentration. Compute the average (mean) RR and the RSD of the 6 RRs. If
the RR for any native compound is constant (less than 30% RSD), the average
RR may be used for that compound; otherwise, the complete calibration curve for
that compound must be used over the calibration range.
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Method 1698 December 2007
10.5 Calibration by internal standard - Internal standard calibration is applied to the
determination of the native compounds for which a labeled compound is not available,
and to determination of the labeled compounds so that their recoveries can be measured.
The reference compound for each native compound is listed in Table 2. For the labeled
compounds, calibration is performed at a single concentration, using data from the 6 (or
5) points in the calibration (Section 10.4).
10.5.1 Response factors - Using data from the 6 (or 5) points in the calibration,
determine the response factor (RF) of each native compound that does not have a
labeled analog and each labeled compound relative to the internal standard using
the area responses of both the primary and secondary exact m/zs specified in
Table 2, for each calibration standard.
Use the internal standards listed in Table 2 as the quantitation reference, the two
exact m/zs listed in Table 2 for quantitation, and the following equation:
RF=(A1S+A2S)CIS
(A1IS+A2IS)CS
Where:
Als and A2S = The areas of the primary and secondary m/zs for the native or
labeled compound
A11S and A21S = The areas of the primary and secondary m/zs for the Labeled
injection internal standard.
C;s = The concentration of the Labeled injection internal standard
(Table 4).
Cs = The concentration of the compound in the calibration standard
(Table 4).
10.5.2 Linearity - Store the response factor (RF) for each native compound at each
concentration. Compute the average (mean) RF and the RSD of the 6 RFs. If the
RF for any native compound is constant (less than 35% RSD), the average RF
may be used for that compound. Otherwise, the complete calibration curve for
that compound must be used over the calibration range. Because the labeled
compounds are present in each calibration standard at the same concentration,
linearity of the labeled compounds is not assessed.
11.0 Sample Preparation
Sample preparation involves modifying the physical form of the sample so that the analytes can
be extracted efficiently. In general, the samples must be in a liquid form or in the form of finely
divided solids in order for efficient extraction to take place. Table 13 lists the phases and
suggested quantities for extraction of various sample matrices. For samples known or expected to
contain high levels of the analytes, the smallest sample size representative of the entire sample
should be used.
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Method 1698 December 2007
Solid samples are prepared per Section 11.4, extracted per Sections 12.2 and cleaned up
according to Section 13.2 and 13.3.
Biosolids are prepared per Section 11.5, extracted per Sections 12.2, and cleaned up according to
Sections 13.2 and 13.3.
Aqueous samples - Because the analytes may be bound to suspended particles, the preparation of
aqueous samples is depends on the presence of visible particles. Aqueous samples absent visible
particles are prepared per Section 11.3 and extracted and cleaned up according to Sections 12.1
13.2 and 13.3.
Aqueous samples with visible particles - If visible particles can be seen in aqueous samples they
should be filtered and the solids and aqueous portions of these samples should be extracted and
combined prior to clean up as follows. Filtration of particles - assemble a clean filtration
apparatus (Section 6.6). Apply vacuum to the apparatus, and pour the entire contents of the
sample bottle through the filter, swirling the sample remaining in the bottle to suspend any
particles. Rinse the sample bottle twice with approximately 5 mL portions of reagent water to
transfer any remaining particles onto the filter. Rinse any particles off the sides of the filtration
apparatus with small quantities of reagent water. Weigh the empty sample bottle to ±1 g.
Determine the weight of the sample by difference. Save the bottle for further use. Prepare and
extract the filtrate using the procedure in Section 11.3. Prepare and extract the filter containing
the particles using the same procedure for biosolids or solid samples as discussed above. These
extracts should be combined prior to analysis (Section 14) or results of separate analysis
combined. It should be noted that the judgment of the analyst must be used to determine the need
to analyze samples with visible particles that compose less than 1 % of the sample weight per
Section 11.1.
Procedures for grinding, homogenization, and blending of various sample phases are given in
Section 11.6.
11.1 Determination of solids content
The solids content of the bulk sample is determined from a subsample that is used only for the
solids determination. Separate procedures are used for the solids determination, based on the
sample matrix, as described below.
11.1.1 Aqueous liquids and multi-phase samples consisting of mainly an aqueous phase
11.1.1.1 Dry a GF/A filter (Section 6.10.3) and weigh it to three significant
figures. Mix the bulk sample in the original container (e.g., cap the
bottle and shake it by hand) and take a 10.0 V 0.2 mL aliquot. Filter
that aliquot through the filter. Dry the filter in an oven for a minimum
of 12 hours at 110 V 5 EC and cool in a dessicator.
11.1.1.2 Weigh the filter and calculate percent solids as follows:
Weight of sample aliquot after drying (g) - weight of filter (g)
/o oOllQS — X lUU
10 g
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Method 1698 December 2007
11.1.2 Non-aqueous liquids, solids, semi-solid samples, biosolids samples, and multi-
phase samples in which the main phase is not aqueous
11.1.2.1 Weigh 5 to 10 g of the bulk sample to three significant figures in a
tared beaker, weighing pan, or other suitable container. Dry for a
minimum of 12 hours at 110 V 5 EC, and cool in a dessicator.
Note: See Section 11.5 for additional considerations in preparing
samples of biosolids.
11.1.2.2 Weigh the dried aliquot and calculate percent solids as follows:
% Solids = Weight of sample aliquot after drying (g) x 1Q()
Weight of sample aliquot before drying (g)
11.2 Estimation of particle size
Extraction of any sample matrix is affected by the size of particles in the sample. Ideally,
the particles should be 1 mm or less. The particle size can be estimated using the sample
aliquot filtered or dried in Sections 11.1.1 or 11.1.2. Spread the aliquot on a piece of
filter paper or aluminum foil in a fume hood or glove box. Visually estimate the size of
the particles in the sample. If the size of the largest particles is greater than 1 mm, use
one of the procedures in Section 11.6 to reduce the particle size to 1 mm or less prior to
extraction. If the largest particles are 1 mm or less, proceed with sample preparation,
using the procedures in Section 11.3, 11.4, or 11.5.
11.3 Preparation of aqueous samples with no visible particles and QC aliquots
11.3.1 Mark the original level of the sample on the sample bottle for reference. Weigh
the sample plus bottle to ± 1 g.
11.3.2 For complex wastewaters (e.g., untreated effluents, in-process streams), spike 1.0
mL of the labeled standard spiking solution (Section 7.14) into the sample bottle.
If the sample is expected to contain a high level of cholesterol, spike 1.0 mL of
the labeled cholesterol spiking solution (Section 7.15) into the sample bottle. For
clean waters (e.g., ambient waters, finished drinking waters, secondary
biologically treated effluents), spike only 40 (iL of the labeled standard spiking
solution into the sample bottle. Cap the bottle and mix the sample by shaking.
Allow the sample to equilibrate for 1 to 2 hours, with occasional shaking.
11.3.3 Blank and OPR aliquots - For each sample or sample batch (to a maximum of 20
samples) to be extracted during the same 12-hour shift, place two 1.0-L aliquots
of reagent water in clean sample bottles or flasks. Spike the volume of labeled
standard spiking solution (1.0 mL or 40 yL) that was spiked into the sample
(Section 11.3.2) into both reagent water aliquots. One of these aliquots will serve
as the method blank. Spike 1.0 mL or 40 (iL of the native standard spiking
solution (Section 7.13), consistent with the volume of labeled compound spiked
into the sample (Section 11.3.2), into the remaining reagent water aliquot. This
aliquot will serve as the OPR (Section 15.5).
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Method 1698 December 2007
Note: It is not necessary to spike the labeled cholesterol spiking solution into
the QC aliquots.
11.3.4 Cap the bottles and mix the QC aliquots by shaking. Allow the QC aliquots to
equilibrate for 1 to 2 hours, with occasional shaking.
11.3.5 Proceed to Section 12.1 for extraction.
11.4 Preparation of solids and filtered solids from aqueous samples. This excludes biosolids.
For biosolids samples, proceed to Section 11.5.
11.4.1 Homogenize the sample in its original container, by shaking samples that are
pourable liquids, or by stirring solids in their original container with a clean
spatula, glass stirring rod, or other suitable implement.
11.4.2 Weigh a well-mixed aliquot of each sample sufficient to provide 10 g of dry
solids (based on the solids determination in Section 11.1.2) into a clean beaker or
glass jar, to a maximum of 1 L of sample. If the particle size estimate (Section
11.2) indicates that size reduction is required, use one of the procedures in
Section 11.6 to reduce the particle size of the 10-g aliquot.
11.4.3 Spike 1.0 mL of the labeled standard spiking solution (Section 7.14) into the
sample. If the sample is expected to contain a high level of cholesterol, spike 1.0
mL of the labeled cholesterol spiking solution (Section 7.15) into the sample.
11.4.4 Blank and OPR aliquots - For each sample or sample batch (to a maximum of 20
samples) to be extracted during the same 12-hour shift, place two 10-g aliquots of
sand, or other appropriate reference matrix (Section 7.8) in clean sample bottles
or flasks. Spike 1.0 mL of the labeled standard spiking solution (Section 7.14)
into both aliquots. One of these aliquots will serve as the method blank. Spike
1.0 mL of the native standard spiking solution (Section 7.13) into the remaining
reagent water aliquot. This aliquot will serve as the OPR (Section 15.5).
Note: It is not necessary to spike the labeled cholesterol spiking solution into
the QC aliquots.
11.4.5 Stir or tumble and equilibrate the aliquots for 1 to 2 hours.
11.4.6 If the sample can be filtered, filter through a glass-fiber filter (Section 6.10.3).
Collect the filtrate in a separatory funnel or continuous liquid-liquid extractor and
proceed to Section 12.1 for extraction of the filtrate and Section 12.2 for
extraction the material remaining on the filter.
11.4.7 If the sample cannot be filtered, proceed to Section 12.2 for extraction of the
sample.
11.5 Preparation of biosolids samples
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Method 1698 December 2007
As noted in Section 8, biosolids may be produced and managed in a variety of forms, and
these will dictate how the samples are collected, prepared, and analyzed. Some biosolids
contain less than 1% solids and are treated in a manner similar to aqueous samples, as
described in Section 11.5.1. Biosolids containing 1 - 5% solids are filtered and the
filtrate and solid material are both extracted, as described in Section 11.5.2. Biosolids
containing greater than 5% solids are mixed with mixed with a small amount of reagent
water and extracted as described in Section 11.5.3.
Because of the likelihood that large amounts of sterols and hormones may be present in
biosolids, the mass of dry solids used for the analysis is greatly reduced from that used
for other solid matrices, down to 0.25 g of dry solids.
When biosolids are managed by composting, they often contain large amounts of sticks,
wood chips, and/or leaves. These materials will contain plant sterols that may interfere
with the analysis of the target analytes in this method. Therefore, the analyst should
carefully remove any large visible plant material from the sample before determining the
solids content in Section 11.1.2.
11.5.1 Biosolids containing less than 1% solids
Pourable liquid biosolids with less than 1% solids should be filtered and the
filtrate analyzed according to the procedure for aqueous samples and the solids
analyzed according to section 11.5.2.
11.5.2 Biosolids containing 1 - 5% solids
11.5.2.1 Homogenize the sample in its original container, by shaking samples
that are pourable liquids, or by stirring solids in their original
container with a clean spatula, glass stirring rod, or other suitable
implement.
11.5.2.2 Using the percent solids determined in Section 11.1.2, determine the
volume of sample that will provide 0.25 g of biosolids. Place this
volume of sample into a clean beaker.
11.5.2.3 Spike 1.0 mL of the labeled standard spiking solution (Section 7.14)
into the sample. For all biosolids samples, spike 1.0 mL of the labeled
cholesterol spiking solution (Section 7.15) into the sample.
11.5.2.4 For each sample or sample batch (to a maximum of 20 samples) to be
extracted during the same 12-hour shift, place two 0.25-g aliquots of
sand, or other appropriate reference matrix (Section 7.8) in clean
sample bottles or flasks. Spike 1.0 mL of the labeled standard spiking
solution (Section 7.14) into both aliquots. One of these aliquots will
serve as the method blank. Spike 1.0 mL of the native standard
spiking solution (Section 7.13) into the remaining QC aliquot. This
aliquot will serve as the OPR (Section 15.5).
Note: It is not necessary to spike the labeled cholesterol spiking
solution into the QC aliquots.
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Method 1698 December 2007
11.5.2.5 Stir or tumble and equilibrate the samples and QC aliquots for 1 to 2
hours.
11.5.2.6 If the sample can be filtered, filter through a glass-fiber filter (Section
6.10.3). Collect the filtrate in a separatory funnel or continuous
liquid-liquid extractor and proceed to Section 12.1 for extraction of
the filtrate and Section 12.2 for extraction of the material remaining
on the filter. If the sample cannot be filtered, proceed to Section 12.2
for extraction of the sample.
11.5.3 Biosolids containing greater than 5% solids
11.5.3.1 Homogenize the sample by stirring solids in the original container
with a clean spatula, glass stirring rod, or other suitable implement.
11.5.3.2 Using the percent solids determined in Section 11.1.2, determine the
volume of sample that will provide 0.25 g of biosolids. Place this
volume of sample into a clean beaker.
11.5.3.3 For each sample or sample batch (to a maximum of 20 samples) to be
extracted during the same 12-hour shift, place two 0.25-g aliquots of
sand, or other appropriate reference matrix (Section 7.8) in clean
sample bottles or flasks.
11.5.3.4 Add 5 mL of reagent water (Section 7.8.1) to the sample and QC
aliquots and mix thoroughly with clean spatulas.
11.5.3.5 Spike 1.0 mL of the labeled standard spiking solution (Section 7.14)
into the sample and both QC aliquots. For all biosolids samples, spike
1.0 mL of the labeled cholesterol spiking solution (Section 7.15) into
the sample.
Note: It is not necessary to spike the labeled cholesterol spiking
solution into the QC aliquots.
11.5.3.6 Spike 1.0 mL of the native standard spiking solution (Section 7.13)
into one of the QC aliquots. This aliquot will serve as the OPR
(Section 15.5). The other aliquot will serve as the blank.
11.5.3.7 Mix the sample and each QC aliquot thoroughly. Cover the bottles or
flasks with foil and allow to equilibrate for 30-60 minutes.
11.5.3.8 Proceed to Section 12.2 for extraction.
11.6 Sample grinding, homogenization, or blending
Samples with particle sizes greater than 1 mm (as determined in Section 11.2) are
subjected to grinding, homogenization, or blending. The method of reducing particle size
to less than 1 mm is matrix-dependent. In general, hard particles can be reduced by
30
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Method 1698 December 2007
grinding with a mortar and pestle. Softer particles can be reduced by grinding in a Wiley
mill or meat grinder, by homogenization, or in a blender.
11.6.1 Each size-reducing preparation procedure on each matrix must be verified by
running the tests in Section 9.2 before the procedure is employed routinely.
11.6.2 The grinding, homogenization, or blending procedures must be carried out in a
glove box or fume hood to prevent particles from contaminating the work
environment.
11.6.3 Grinding - Amorphous and other solids can be ground in a Wiley mill or heavy
duty meat grinder. In some cases, reducing the temperature of the sample to
freezing or to dry ice or liquid nitrogen temperatures can aid in the grinding
process. Grind the sample aliquots in a clean grinder. Do not allow the sample
temperature to exceed 50 EC. Also grind the blank and OPR reference matrix
aliquots using a clean grinder.
11.6.4 Homogenization or blending - Particles that are not ground effectively, or
particles greater than 1 mm in size after grinding, can often be reduced in size by
high speed homogenization or blending. Homogenize and/or blend the particles
or filter for the sample, blank, and OPR aliquots.
11.6.5 After size reduction, return to Section 11.4 for the preparation of solid samples
and QC aliquots, or Section 11.5 forbiosolid samples and QC aliquots.
12.0 Extraction and Concentration
Extraction procedures include: separatory runnel (Section 12.1.1) and continuous liquid/liquid
(Section 12.1.2) for aqueous liquids, and Soxhlet extraction (Section 12.2) for solids and
biosolids. Extracts may be concentrated using rotary evaporation (Section 12.3.1), a heating
mantle (Section 12.3.2), or Kuderna-Danish (Section 12.3.3). Microconcentration is performed
by nitrogen evaporation (Section 12.4).
Note: Whichever combination of extraction and concentration techniques is used for samples
must also be used for the associated QC aliquots.
12.1 Extraction of aqueous liquids
If the sample was filtered in Section 11.4.6 or 11.5.2.6, the filtrate is extracted using one
of the aqueous procedures in Section 12.1.1 or 12.1.2, and the solids on the filter are
extracted using the solids procedure in Section 12.2.
12.1.1 Separatory funnel extraction
12.1.1.1 Pour the sample (Section 11.3.2) into a 2-L separatory funnel. Rinse
the bottle or flask twice with 5 mL of reagent water and add these
rinses to the separatory funnel. Add 100 mL methylene chloride to the
empty sample bottle. Cap the bottle and shake 60 seconds to rinse the
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Method 1698 December 2007
inner surface. Transfer the solvent to the separatory funnel, and extract
the sample by shaking the funnel for 2 minutes with periodic venting.
12.1.1.2 Allow the organic layer to separate from the aqueous phase for a
minimum of 10 minutes. If an emulsion forms and is more than one-
third the volume of the solvent layer, employ mechanical techniques to
complete the phase separation (see note below).
12.1.1.3 Drain the methylene chloride extract through a solvent-rinsed glass
funnel approximately one-half full of granular anhydrous sodium
sulfate (Section 7.2.1) supported on clean glass-fiber paper into a
solvent-rinsed concentration device (Section 12.3).
Note: If an emulsion forms, the laboratory must employ mechanical techniques
to complete the phase separation. The optimum technique depends upon
the sample, but may include stirring, filtration through glass wool, use of
phase separation paper, centrifugation, use of an ultrasonic bath with ice,
addition of NaCl, or other physical methods. Alternatively, continuous
liquid-liquid extraction (Section 12.1.2), or other extraction techniques
may be used to prevent emulsion formation. Any alternative technique is
acceptable so long as the requirements in Section 9.2 are met.
12.1.1.4 Extract the water sample two more times with 100-mL portions of
methylene chloride. Drain each portion through the sodium sulfate
into the concentrator. After the third extraction, rinse the separatory
funnel with at least 20 mL of methylene chloride, and drain this rinse
through the sodium sulfate into the concentrator. Repeat this rinse at
least twice. Concentrate the extract per Section 12.3.
12.1.2 Continuous liquid/liquid extraction
12.1.2.1 Place 100-150 mL methylene chloride in the continuous extractor and
200-300 mL in the distilling flask. Pour the sample into the extractor.
Rinse the sample container with 50-100 mL methylene chloride and
add to the extractor.
12.1.2.2 Begin the extraction by heating the flask until the methylene chloride
is boiling. When properly adjusted, 1-2 drops of methylene chloride
per second will fall from the condenser tip into the water. Extract for
16-24 hours.
12.1.2.3 Remove the distilling flask, estimate and record the volume of extract
(to the nearest 100 mL) and pour the contents through a drying column
containing 7 to 10 cm of granular anhydrous sodium sulfate into the
concentration flask. Rinse the distilling flask with 30-50 mL of
methylene chloride and pour through the drying column. Concentrate
the extract per Section 12.3.
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Method 1698 December 2007
12.2 Soxhlet extraction of biosolids, solid samples and filtered solids from aqueous samples.
12.2.1 Assemble and pre-extract the Soxhlet apparatus for 1 - 2 hours using methylene
chloride or hexane:acetone (40:60). After pre-extraction, disassemble the
apparatus and allow to dry.
12.2.2 Add 80 to 100 g of powdered anhydrous sodium sulfate (Section 7.2.2) to the
beaker containing the sample (Section 11.4.7, 11.5.3, or 11.6.5) and mix
thoroughly. If the sample was filtered in Section 11.4.6 or 11.5.2.6 and the
material to be extracted is on the filter, place the filter in a beaker and treat as
described here. Cover the beaker with aluminum foil and dry until the mixture
becomes a free-flowing powder (30 minutes minimum). Remix prior to
extraction to prevent clumping.
12.2.3 Re-assemble the pre-extracted Soxhlet apparatus and add a fresh charge of
hexane:acetone (40:60) to the reflux flask.
12.2.4 Transfer the sample/sodium sulfate mixture to the Soxhlet thimble, and install the
thimble in the Soxhlet apparatus.
12.2.5 Rinse the beaker with several portions of solvent and add to the thimble. Fill the
thimble/receiver with solvent. Apply power to the heating mantle to begin re-
fluxing. Adjust as necessary to achieve a reflux rate of approximately 4 cycles
per hour. Extract for 16-18 hours.
12.2.6 After extraction, cool and disassemble the apparatus.
12.2.7 Quantitatively transfer the extract to a macroconcentration device with solvent
rinses and concentrate the extract per Section 12.3.
12.3 Macro-concentration
Extracts from aqueous or solid samples may be concentrated using any of the macro-
concentration procedures described below, including: rotary evaporation, a heating mantle, or
Kuderna-Danish concentrator.
If the sample was filtered in Section 11.4.6 or 11.5.2.6 and extracted in Section 12, the extracts of
filtrate and of the solids may be combined prior to concentration or, if it is desirable to know the
concentrations in the aqueous and solids portions separately, the extracts may be concentrated
separately.
Note: In the concentration procedures below, the extract must not be allowed to concentrate to
dryness, because low molecular weight steroid/hormones may be totally or partially lost.
12.3.1 Rotary evaporation concentration - Concentrate the extracts of the sample and
QC aliquots in separate round-bottom flasks.
12.3.1.1 Assemble the rotary evaporator according to manufacturer's
instructions and warm the water bath to 45 ° C. On days when the
apparatus is used, pre-clean the rotary evaporator by concentrating 100
33
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Method 1698 December 2007
mL of clean extraction solvent through the system. Archive both the
concentrated solvent from this pre-cleaning and the solvent in the catch
flask for a contamination check if necessary. Between samples, rinse
down the feed tube with three 2- to 3- mL aliquots of solvent and
collect the rinses in a waste beaker.
12.3.1.2 Add a few clean boiling chips to the round-bottom flask containing the
sample extract and attach the flask to the rotary evaporator. Slowly
apply vacuum to the system, and begin rotating the flask. Lower the
flask into the water bath, and adjust the speed of rotation and the
temperature as required to complete concentration in 15 to 20 minutes.
At the proper rate of concentration, the flow of solvent into the
receiving flask will be steady, but no bumping or visible boiling of the
extract will occur.
Note: If the rate of concentration is too fast, analyte loss may occur.
12.3.1.3 When the liquid in the concentration flask has reached an apparent
volume of approximately 2 mL, remove the flask from the water bath
and stop the rotation. Slowly and carefully admit air into the system.
Be sure not to open the valve so quickly that the extract is blown out of
the flask. If a feed tube is used to feed the sample into the rotary
evaporation apparatus rinse the feed tube with approximately 2 mL of
solvent.
12.3.1.4 Quantitatively transfer the extract to an Erlenmeyer flask. If there is
evidence of water in the round-bottom flask after the transfer, rinse the
flask with hexane:acetone (40:60) and add to the Erlenmeyer flask.
Mark and set aside the concentration flask for future use.
12.3.1.5 Add 10 - 20 g of granular anhydrous sodium sulfate to the Erlenmeyer
flask to dry the extract. If sulfur is known or suspected to be present in
the sample, and for all biosolids samples, add activated copper (Section
7.6.3) to remove the sulfur. Cover and allow to the extract dry and
remove sulfur for 30 - 60 minutes, swirling occasionally.
12.3.1.6 After drying and sulfur removal, quantitatively transfer the extract to a
vial or tube and proceed to Section 12.4 for microconcentration and
solvent exchange, taking care to leave the sodium sulfate and copper
foil in the flask.
12.3.2 Heating mantle concentration - Concentrate the extracts of the sample and QC
aliquots in separate round-bottom flasks.
12.3.2.1 Add a few clean boiling chips to the round-bottom flask, and attach a
three-ball macro Snyder column. Prewet the column by adding
approximately 1 mL of solvent through the top. Place the round-
bottom flask in a heating mantle, and apply heat as required to
complete the concentration in 15 to 20 minutes. At the proper rate of
distillation, the balls of the column will actively chatter, but the
chambers will not flood.
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Method 1698 December 2007
12.3.2.2 When the liquid has reached an apparent volume of approximately 10
mL, remove the round-bottom flask from the heating mantle and allow
the solvent to drain and cool for at least 10 minutes. Remove the
Snyder column and rinse the glass joint into the flask with small
portions of solvent.
12.3.2.3 Quantitatively transfer the extract to an Erlenmeyer flask. If there is
evidence of water in the flask after the transfer, rinse the flask with
hexane:acetone (40:60) and add to the Erlenmeyer flask. Mark and set
aside the flask and macro Snyder column for future use.
12.3.2.4 Add 10 - 20 g of granular anhydrous sodium sulfate to the Erlenmeyer
flask to dry the extract. If sulfur is known or suspected to be present in
the sample, and for biosolids samples, add activated copper (Section
7.6.3) to remove the sulfur. Cover and allow to dry for 30 - 60
minutes, swirling occasionally.
12.3.2.5 After drying and sulfur removal, quantitatively transfer the extract to a
vial or tube and proceed to Section 12.4 for microconcentration and
solvent exchange, taking care to leave the sodium sulfate and copper
foil in the flask.
12.3.3 Kuderna-Danish (K-D) concentration
Note: The K-D technique is most useful for solvents such as methylene
chloride, acetone, and hexane, which boil at temperatures well below 100
°C. Toluene is difficult to concentrate using the K-D technique unless a
water bath fed by a steam generator is used. Therefore, K-D
concentration may not be as useful for sample extracts that have been
subjected to the layered alumina/Florisil cleanup in Section 13 as other
macroconcentration techniques.
12.3.3.1 Add 1 to 2 clean boiling chips to the K-D receiver. Attach a three-ball
macro Snyder column. Pre-wet the column by adding approximately 1
mL of solvent through the top.
12.3.3.2 Place the K-D apparatus in a hot water bath so that the entire lower
rounded surface of the flask is bathed with steam. Adjust the vertical
position of the apparatus and the water temperature as required to
complete the concentration in 15 to 20 minutes. At the proper rate of
distillation, the balls of the column will actively chatter but the
chambers will not flood.
12.3.3.3 When the liquid has reached an apparent volume of 1 mL, remove the
K-D apparatus from the bath and allow the solvent to drain and cool
for at least 10 minutes. Remove the Snyder column and rinse the flask
and its lower joint into the concentrator tube with 1 to 2 mL of solvent.
A 5-mL syringe is recommended for this operation.
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Method 1698 December 2007
12.3.3.4 Remove the three-ball Snyder column, add a fresh boiling chip, and
attach a two-ball micro Snyder column to the concentrator tube. Pre-
wet the column by adding approximately 0.5 mL of solvent through the
top. Place the apparatus in the hot water bath.
12.3.3.5 Adjust the vertical position and the water temperature as required to
complete the concentration in 5 to 10 minutes. At the proper rate of
distillation, the balls of the column will actively chatter but the
chambers will not flood.
12.3.3.6 When the liquid reaches an apparent volume of 0.5 mL, remove the
apparatus from the water bath and allow to drain and cool for at least
10 minutes. If sulfur is known or suspected to be present in the
sample, and for biosolids samples, add activated copper (Section
7.6.3). Cover and allow to stand for 30 - 60 minutes with occasional
swirling to remove the sulfur.
12.3.3.7 After drying and sulfur removal, quantitatively transfer the extract to a
vial or tube and proceed to Section 12.4 for micro-concentration and
solvent exchange.
12.4 Micro-concentration and solvent exchange by nitrogen evaporation
Micro-concentration is used to reduce the volume of a sample extract to the volume
required for cleanup or for derivatization and analysis. The layered alumina/Florisil
column cleanup requires solvent exchange to 5% toluene in hexane; injection of a
derivatized extract into the GC/HRMS requires solvent exchange to hexane (Section
13.3).
If the extract will not cleaned up, or already has been cleaned up, and it was spiked with
the labeled cholesterol spiking solution (Section 7.15), adjust the volume to 50 mL. Take
a 2-mL aliquot from this solution and separately concentrate both portions (2-mL and 48-
mL) for derivatization (Section 13.3) and analysis (Section 14).
12.4.1 Transfer the tube or vial containing the sample extract to a nitrogen evaporation
device. Adjust the flow of nitrogen so that the surface of the solvent is just
visibly disturbed.
Note: A large vortex in the solvent may cause analyte loss.
12.4.2 Lower the vial into a 45 EC water bath and continue concentrating. When the
volume of the liquid is approximately 100 |oL, add 2 to 3 mL of the desired
solvent (5% toluene in hexane for the layered alumina/Florisil cleanup, or hexane
for derivatization) and concentrate to approximately 100 |oL. Repeat the addition
of solvent and concentrate to approximately 100 joL once more.
12.4.3 If the extract is to be cleaned up by layered alumina/Florisil column, bring the
final volume to 1.0 mL with 5% toluene in hexane and proceed with cleanup
(Section 13.2).
36
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Method 1698 December 2007
12.4.4 If the extract is not to be cleaned up, or has been cleaned up, proceed to Section
13.3 for derivatization.
13.0 Cleanup and Derivatization
13.1 Cleanup may not be necessary for relatively clean samples (e.g., treated effluents,
groundwater, drinking water). If particular circumstances require the use of a cleanup
procedure, the laboratory may use the procedure below or any other procedure but the
laboratory must demonstrate that the requirements of Section 9.2 can be met using any
cleanup procedure.
The layered alumina/Florisil (LAP) column (Section 13.2) has been shown to be
especially effective for cleanup of untreated wastewaters from publicly owned treatment
works (POTWs) and for biosolids. Prior to employing this cleanup, the laboratory must
establish that the recommended elution volumes and collection points (cut points) are
effective in processing the standards containing the analytes of interest in this method.
That process is described in Section 13.2.2.
13.2 Layered alumina/Florisil (LAP) cleanup
Note: Exposure of the column and packing to moisture from the air should be
minimized to prevent moisture from altering the elution volumes.
13.2.1 Column preparation
13.2.1.1 Separately prepare slurries of 5 g each of 5% deactivated alumina
(Section 7.6.1) and 5% deactivated Florisil (Section 7.6.2) in methanol.
Slurry pack the column first with the alumina followed by the Florisil.
13.2.1.2 Top the column with approximately 1 g of granular, anhydrous sodium
sulfate (Section 7.2.1). Flush the column with 2 bed volumes of
methanol followed by 2 bed volumes of 5% toluene in hexane. Allow
the solvent to drain until just to the top of, but not below, the sodium
sulfate layer.
13.2.2 Confirming the cut points for the LAP column
This method recommends elution volumes for collection of two chromatographic
fractions (Fl and F2) of the material processed through the LAP column cleanup.
Each laboratory must confirm that these volumes and collection cut points are
appropriate for the LAP columns they prepare. This demonstration must be
performed during the start-up phase of using the method, should be repeated if
major changes in laboratory practices occur, and when column reagents from
different lots or suppliers are to be employed.
Note: The cut point confirmation is not required with each batch of extracts
processed through cleanup.
37
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Method 1698 December 2007
13.2.2.1 Exchange an underivatized 500-(iL aliquot of the CS-3 calibration
solution (Table 4) to 5% toluene in hexane using the procedure in
Section 12.4. An existing or expired standard may be used for this
purpose. Bring to 1.0 mL volume.
Typical cut-points are as follows:
Fraction 1 (Fl) - 5% toluene in hexane, 15 mL (discard) and
Fraction 2 (F2) - MeOH, 50 mL (collect).
13.2.2.2 Elute the column and separately collect volumes of 10, 15, and 20 mL
of 5% toluene in hexane, then 50 mL of methanol, or other volumes as
necessary to characterize the elution.
13.2.2.3 Analyze each of these four fractions to determine the maximum
volume of 5% toluene in hexane that can be discarded without loss of
the steroids/ hormones. 15 mL was found to be effective in validation
of this method. GC/LRMS may be used for this test, if desired. Once
the elution volumes are established, they are used with the same batch
of adsorbents for all samples, blanks, IPRs, and OPRs.
13.2.3 Extract clean up
13.2.3.1 Pack a fresh LAP column (Section 13.2.1) each for the sample and QC
aliquot. Carefully place the extract of the sample or QC aliquot on the
top of the column with 2 rinses of 5% toluene in hexane and elute to
the top of, but not below, the sodium sulfate layer.
13.2.3.2 If sulfur is known or suspected to be present in the sample, and for all
biosolids samples, add activated copper (Section 7.6.3) to remove the
sulfur. Refer to the most recent cut-point determination for elution
volumes. Elute the LAP column with 5% toluene in hexane (Fl, 15
mL or other volume as determined in cut point determination) and
discard the eluate.
13.2.3.3 Elute the column with MeOH (F2). Collect the eluate in a 125-mL
round-bottom flask. F2 contains the sterols and hormones.
Note: Samples containing high levels of sterols (and to which an aliquot of
high level labeled cholesterol standard has been added) are split before
proceeding.
12.2.3.4 Quantitatively transfer a 2 mL aliquot of the 50 mL extract to a
centrifuge tube. Label this portion as a dilution of the original sample.
Concentrate to about 1 mL by evaporation under nitrogen. Concentrate
the remaining 48 mL of extract to 1 mL macro- and/or micro-
concentration and transfer to another centrifuge tube with methylene
chloride rinses.
38
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Method 1698 December 2007
12.2.3.5 Prior to analysis, both portions of the F2 extract must be silylated to
convert the sterols and hormones to their trimethylsilyl ethers.
13.2.3.6 Proceed with silylation (Section 13.3).
13.3 Derivatization by silylation
13.3.1 Quantitatively transfer the concentrated extract (Section 12.4.4 or 13.2.3.6) to a
centrifuge tube with methylene chloride. For derivatization of a calibration
standard (Section 7.12), add 500 \\L of the standard to a centrifuge tube. Add 50
|oL (approximately 4 drops) of pyridine to the tube(s).
13.3.2 Evaporate to near dryness (50 joL) using nitrogen evaporation (Section 12.4).
Add 300 \\L of methylene chloride and mix using a vortex mixer.
13.3.3 Transfer the extract to a GC/MS vial with methylene chloride rinses and
evaporate to dryness.
13.3.3.1 Extracts of clean waters to be concentrated to 20 \\L - Add 10 \\L of
pyridine to the vial and mix with a vortex mixer. Add 10 (iL of 99:1
BSTFA:TMCS and apply a crimp cap to the vial. Incubate at 55 °C for
30 minutes. Spike with 2 \\L of Labeled injection standard solution
(Section 7.11.3) and evaporate to 20 (iL under nitrogen. Label the vial
with the sample number. Store in the dark at room temperature until
ready for GC/HRMS analysis. If GC/HRMS analysis will not be
performed on the same day, store the vial at less than -10 EC. Proceed
to Section 14 for analysis.
13.3.3.2 Extracts of complex waters and solids - Add 50 (iL of pyridine to the
vial and mix with a vortex mixer. Add 50 (iL of 99:1 BSTFA:TMCS
and apply a crimp cap to the vial. Incubate at 55 °C for 15 minutes.
Add another 50 (iL of BSTFA:TMCS and incubate for 15 minutes.
Spike with 50 \\L of Labeled injection internal standard solution
(Section 7.11.3) and bring to 500 \\L with hexane. Label the vial with
the sample number. Store in the dark at room temperature until ready
for GC/HRMS analysis. If GC/HRMS analysis will not be performed
on the same day, store the vial at less than -10 EC. Proceed to Section
14 for analysis.
14.0 HRGC/HRMS Analysis
14.1 Establish the operating conditions given in Section 10.1.1. Bring the extract to room
temperature.
14.2 If an extract is to be re-analyzed and evaporation has occurred, do not add more labeled
injection internal standard stock solution. Rather, bring the extract back to its previous
volume (20 or 500 |oL) with hexane.
39
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Method 1698 December 2007
14.3 Inject 1.0 or 2.0 joL of the concentrated extract using on-column or splitless injection.
The volume injected must be identical to the volume used for calibration (Section 10.3).
14.3.1 Start the GC column initial isothermal hold upon injection. Start MS data
collection after the solvent peak elutes.
14.3.2 Monitor the exact m/zs for each steroid/hormone throughout its retention time
window. Where warranted, monitor m/zs associated with interferents expected to
be present.
14.3.3 Stop data collection after p-Estradiol-3-benzoate elutes. Return the column to
the initial temperature for analysis of the next sample extract or standard.
15.0 System and Laboratory Performance
15.1 At the beginning of each 12-hour shift during which analyses are performed, GC/MS
system performance and calibration are verified for all the steroid/hormones and labeled
compounds. For these tests, analysis of the CS-3 calibration verification (VER) standard
(Section 7.12 and Table 4) must be used to verify all performance criteria. Adjustment
and/or recalibration (Section 10) must be performed until all performance criteria are
met. Only after all performance criteria are met may samples, blanks, IPRs, and OPRs be
analyzed.
15.2 MS resolution - Static resolving power checks must be performed at the beginning of
each shift per Sections 10.2. If the requirements in Section 10.2 cannot be met, the
problem must be corrected before analyses can proceed. If any of the samples in the
previous shift may be affected by poor resolution, those samples must be re-analyzed.
15.3 Calibration verification
15.3.1 Inject the derivatized VER (CS-3) calibration standard using the procedure in
Section 14.
15.3.2 The m/z abundance ratios for all steroid/hormones must be within the limits in
Table 2 or in the most recent calibration; otherwise, the mass spectrometer must
be adjusted until the m/z abundance ratios fall within the limits specified when
the verification test is be repeated. If the adjustment alters the resolution of the
mass spectrometer, resolution must be verified (Section 10.2) prior to repeat of
the verification test.
15.3.3 The GC peaks representing each native steroid/hormone and labeled compound
in the VER standard must be present with a S/N of at least 10; otherwise, the
mass spectrometer must be adjusted and the verification test repeated.
15.3.4 Compute the concentration of the steroid/hormones that have labeled analogs by
isotope dilution and the concentration of the steroid/hormones that do not have
labeled analogs, and of the labeled compounds, by the internal standard
technique. These concentrations are computed based on the calibration data in
Section 10.
40
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Method 1698 December 2007
15.3.5 For each compound, compare the concentration with the calibration verification
limit in Table 5. If all compounds meet the acceptance criteria, calibration has
been verified and analysis of standards and sample extracts may proceed. If,
however, any compound fails its respective limit, the measurement system is not
performing properly. In this event, prepare a fresh calibration standard or correct
the problem and repeat the resolution (Section 15.2) and verification (Section
15.3) tests, or recalibrate (Section 10).
15.4 Retention times and GC resolution
15.4.1 Retention times
15.4.1.1 The absolute retention times of the labeled compounds (Section 7.14)
in the verification test (Section 15.3) must be within V 15 seconds of
the respective retention times in the calibration (Section 10.1).
15.4.1.2 The relative retention times of native steroid/hormones and the labeled
compounds in the verification test (Section 15.3) must be within their
respective RRT limits in Table 2 or, if an alternative column or column
system is employed, within their respective RRT limits for the
alternative column or column system (Section 9.1.2.3).
15.4.1.3 If the absolute or relative retention time of any compound is not within
the limits specified, the GC is not performing properly. In this event,
adjust the GC and repeat the verification test (Section 15.3) or
recalibrate (Section 10), or replace the GC column and either verify
calibration or recalibrate.
15.4.2 GC resolution and minimum analysis time
15.4.2.1 The resolution and minimum analysis time specifications in
Sections 6.18.2 and 10.1.2.2, respectively, must be met for
the RTx-5 column or, if an alternative column or column
system is employed, must be met as specified for the
alternative column or column system (Section 9.1.2.3). If
these specifications are not met, the GC analysis conditions
must be adjusted until the specifications are met, or the
column must be replaced and the calibration verification
tests repeated Sections 15.3 - 15.4), or the system must be
recalibrated (Section 10).
15.4.2.2 After the resolution and minimum analysis time
specifications are met, update the retention times and relative
retention times, but not the relative responses and response
factors. For the relative responses and response factors, the
multi-point calibration data (Sections 10.4 and 10.5) must be
used.
41
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Method 1698 December 2007
15.5 Ongoing precision and recovery
15.5.1 Analyze the derivatized extract of the ongoing precision and recovery (OPR)
aliquot (Section 11.3.3, 11.4.5, 11.5.2.5, or 11.5.3.7) prior to analysis of samples
from the same batch.
15.5.2 Compute the percent recovery of each steroid/hormone with a labeled analog by
isotope dilution (Section 10.4). Compute the percent recovery of each native
compound without a labeled analog, and of each labeled compound, by the
internal standard method (Section 10.5).
15.5.3 For the native and labeled compounds, compare the recovery to the OPR limits
given in Table 5. If all compounds meet the acceptance criteria, system
performance is acceptable and analysis of blanks and samples may proceed. If,
however, any individual concentration falls outside of the range given, the
extraction/concentration processes are not being performed properly for that
compound. In this event, correct the problem, re-prepare, extract, and clean up
the sample batch and repeat the ongoing precision and recovery test.
15.5.4 If desired, add results that pass the specifications in Section 15.5.3 to initial and
previous ongoing data for each compound in each matrix. Update QC charts to
form a graphic representation of continued laboratory performance. Develop a
statement of laboratory accuracy for each steroid and hormone in each matrix
type by calculating the average percent recovery (R) and the standard deviation
of percent recovery (SR). Express the accuracy as a recovery interval from R !
2SR to R + 2SR. For example, if R = 95% and SR = 5%, the accuracy is 85 to
105%.
15.6 Blank - Analyze the method blank extracted with each sample batch immediately
following analysis of the OPR aliquot to demonstrate freedom from contamination and
freedom from carryover from the OPR analysis. If steroid/hormones will be carried from
the OPR into the method blank, analyze one or more aliquots of solvent between the OPR
and the method blank. The results of the analysis of the blank must meet the
specifications in Section 9.5.2 before sample analyses may proceed.
16.0 Qualitative Determination
A steroid/hormone or labeled compound is identified in a standard, blank, or sample when all of
the criteria in Sections 16.1 through 16.4 are met.
16.1 The signals for the two exact m/zs in Table 2 must be present and must maximize within
the same two scans.
16.2 The signal-to-noise ratio (S/N) for the GC peak at each exact m/z must be greater than or
equal to 2.5 for each compound detected in a sample extract, and greater than or equal to
10 for all compounds in the calibration and verification standards (Sections 10.3.3 and
15.3.3).
42
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Method 1698 December 2007
16.3 The ratio of the integrated areas of the two exact m/zs specified in Table 2 must be within
V30 percent of the theoretical limit in Table 2, or within V30 percent of the ratio in the
midpoint (CS-3) calibration or calibration verification (VER), if the VER is more recent
than the calibration.
16.4 The relative retention time of the peak for a steroid/hormone must be within the window
specified in Table 2 or within similar limits developed from calibration data (Section
10.1.2). If an alternative column (Section 9.1.2.3) is employed, the RRT for the
steroid/hormone must be within its respective RRT QC limits for the alternative column
or column system (Section 6.18.3).
Note: For native steroid/hormones determined by internal standard quantitation, a
steroid/hormone with the same exact m/zs as other steroid/hormones may fall within
more than one RT window and be mis-identified unless the RRT windows are made very
narrow, as in Table 2. Therefore, consistency of the RT and RRT with other
steroid/hormones and the labeled compounds may be required for rigorous
steroid/hormone identification. Retention time regression may aid in this identification.
16.5 Because of steroid/hormone RT overlap and the potential for interfering substances, it is
possible that assessment of identification criteria (Sections 16.1 - 16.4) will be difficult.
If identification is ambiguous, an experienced spectrometrist must determine the presence
or absence of the steroid/hormone. Reports of the results must identify any time an
ambiguous identification was made in this manner.
16.6 If the criteria for identification in Sections 16.1 - 16.5 are not met, the steroid or hormone
has not been identified and the result for that steroid or hormone may not be reported or
used for permitting or regulatory compliance purposes. If interferences preclude
identification, a new aliquot of sample must be extracted, further cleaned up, and
analyzed.
17.0 Quantitative Determination
17.1 Isotope dilution quantitation
17.1.1 By adding a known amount of a labeled steroid or hormone to each sample prior
to extraction, correction for recovery of each steroid or hormone can be made
because the native compound and its labeled analog exhibit similar effects upon
extraction, concentration, and gas chromatography. Relative responses (RRs) are
used in conjunction with the calibration data in Section 10.4 to determine
concentrations in the final extract, so long as labeled compound spiking levels
are constant.
17.1.2 Compute the concentrations of the steroid or hormone in the extract using the RR
from the calibration data (Section 10.4) and following equation:
(Al,
43
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Method 1 698 December 2007
Where:
Cex = The concentration of the steroid or hormone in the extract, and the other
terms are as defined in Section 10.4.4
17.2 Internal standard quantitation and labeled compound recovery
1 7.2. 1 Compute the concentration in the extract of each native compound that does not
have a labeled analog, and of each labeled compound, using the response factor
determined from the calibration data (Section 10.5) and the following equation:
(Alis + A2is) RF
Where:
Cex = The concentration of the labeled compound in the extract, and the other
terms are as defined in Section 10.5.1
17.2.2 Using the concentration in the extract determined above, compute the percent
recovery of the labeled compound using the following equation:
_. .„,. Concentration found (ng/mL) ,„„
Re cov ery (%) = - — - - - x 100
Concentration spiked (ng/mL)
17.3 The concentration of a native compound in the solid phase of the sample is computed
C V
Concentration in solid sample (ng/kg) = — — — —
Ws
using the concentration of the compound in the extract and the weight of the solids
(Section 11.1.2.2), as follows:
Where:
Cex = The concentration of the compound in the extract (ng/mL)
Vex = The extract volume in mL
Ws = The sample weight (dry weight) in kg
17.4 The concentration of a native compound in the aqueous phase of the sample is computed
using the concentration of the compound in the extract and the volume of water extracted
(Section 11.3), as follows:
C V
Concentration in aqueous sample (ng/L) = — — — — x 1000
*s
Where:
Cex = The concentration of the compound in the extract (ng/mL)
Vex = The extract volume in mL
Vs = The sample volume in liters
44
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Method 1698 December 2007
17.5 Calibration range
17.5.1 If the SICP area at either quantitation m/z for any steroid or hormone exceeds the
calibration range of the system, dilute the sample extract by the factor necessary
to bring the concentration within the calibration range, adjust the concentration of
the Labeled injection internal standard to 1000 ng/mL (pg/joL) in the extract, and
analyze an aliquot of this diluted extract. If a steroid or hormone cannot be
measured reliably by isotope dilution, dilute and analyze an aqueous sample or
analyze a smaller portion of a soil, biosolid, or mixed-phase sample. Adjust the
compound concentrations, detection limit, and minimum level to account for the
dilution.
17.5.2 Cholesterol - Biosolids and other samples may contain concentrations of
cholesterol that exceed the range of the analytical system. If a sample has been
spiked with the labeled cholesterol spiking solution (Section 7.15) and the
cholesterol concentration exceeds the range of the analytical system, the sample
may be diluted and reanalyzed for cholesterol (only) by this method or may be
analyzed by GC/LRMS, if desired.
17.6 Reporting of results
17.6.1 Reporting units
17.6.1.1 Aqueous samples - Report results in ng/L (parts-per-trillion).
17.6.1.2 Samples containing greater than 1% solids (soils, sediments, filter
cake, compost) - Report results in ng/kg based on the dry weight of the
sample. Also report the percent solids.
17.6.2 Reporting level
17.6.2.1 Report the result for each compound in each sample, blank, or standard
(VER, IPR, OPR) at or above the minimum level of quantitation (ML;
Table 2) to 3 significant figures. More significant figures may be used
for computerized reporting. Report the result below the ML in each
sample as
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Method 1698 December 2007
17.6.2.3 Results for a steroid or hormone in a sample that has been diluted are
reported at the least dilute level at which the area at the quantitation
m/z is within the calibration range (Section 17.5).
17.6.2.4 For a steroid or hormone having a labeled analog, report results at the
least dilute level at which the areas at the quantitation m/zs are within
the calibration range (Section 17.5) and the labeled compound
recovery is within the normal range for the method (Section 9.3 and
Table 5).
17.6.2.5 Results from tests performed with an analytical system that is not in
control must not be reported or otherwise used for permitting or
regulatory compliance purposes, but do not relieve a discharger or
permittee of reporting timely results.
18.0 Analysis of Complex Samples
18.1 Some samples may contain high levels (>10 ng/L; >1000 ng/kg) of the compounds of
interest, interfering compounds, and/or polymeric materials. Some extracts may not
concentrate to 500 |oL. Others may overload the GC column and/or mass spectrometer.
18.2 Analyze a smaller aliquot of the sample (Section 17.5) when the extract will not
concentrate to 500 \\L after all cleanup procedures have been exhausted. If a smaller
aliquot of soils or mixed-phase samples is analyzed, attempt to assure that the sample is
representative.
18.3 Perform integration of peak areas and calculate concentrations manually when
interferences preclude computerized calculations.
18.4 Recovery of labeled compounds - In an ideal reference matrix, recoveries of labeled
compounds will be similar to those from the actual sample.
18.4.1 If the recovery of any of the labeled compounds is outside of the normal range
(Table 5), a diluted sample must be analyzed (Section 17.5).
18.4.2 If the recovery of any of the labeled compounds in the diluted sample is outside
of normal range, the calibration verification standard (Section 7.12) must be
analyzed and calibration verified (Section 15.3).
18.4.3 If the calibration cannot be verified, a new calibration must be performed and the
original sample extract reanalyzed.
18.4.4 If calibration is verified and the diluted sample does not meet the limits for
labeled compound recovery, the method does not apply to the sample being
analyzed and the result may not be reported or used for permitting or regulatory
compliance purposes. In this case, alternative extraction and cleanup procedures
in this method or an alternative GC column must be employed to resolve the
interference. If all cleanup procedures in this method and an alternative GC
column have been employed and labeled compound recovery remains outside of
46
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Method 1698 December 2007
the normal range, extraction and/or cleanup procedures that are beyond this scope
of this method will be required to analyze the sample.
19.0 Pollution Prevention
19.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity
or toxicity of waste at the point of generation. Many opportunities for pollution
prevention exist in laboratory operation. EPA has established a preferred hierarchy of
environmental management techniques that places pollution prevention as the
management option of first choice. Whenever feasible, laboratory personnel should use
pollution prevention techniques to address waste generation. When wastes cannot be
reduced at the source, the Agency recommends recycling as the next best option.
19.2 The steroids/hormones in this method are used in extremely small amounts and pose little
threat to the environment when managed properly. Standards should be prepared in
volumes consistent with laboratory use to minimize the disposal of excess volumes of
expired standards.
19.3 For information about pollution prevention that may be applied to laboratories and
research institutions, consult Reference 10.
20.0 Waste Management
20.1 The laboratory is responsible for complying with all Federal, State, and local regulations
governing waste management, particularly the hazardous waste identification rules and
land disposal restrictions, and to protect the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations. Compliance is also
required with any sewage discharge permits and regulations. An overview of
requirements can be found in Reference 11.
20.2 Samples containing HC1 or H2SO4 to pH <2, or KOH or NaOH to pH >12 are hazardous
and must be neutralized before being poured down a drain or must be handled as
hazardous waste.
20.3 The steroid/hormones decompose above 500 EC. Low-level waste such as absorbent
paper, tissues, animal remains, and plastic gloves may be burned in an appropriate
incinerator. Gross quantities (milligrams) should be packaged securely and disposed of
through commercial or governmental channels that are capable of handling extremely
toxic wastes.
20.4 For further information on waste management, consult References 10 and 12.
21.0 Method Performance
This method was developed in a single laboratory, and performance data from this laboratory
are included in Table 7. Additional data will be included as they are developed.
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Method 1698 December 2007
22.0 References
1 EPA Methods 1613, 1614, and 1668A.
2 "Analytical Method for the Determination of Sterols and Hormones with BSTFA
Derivatization and GC/HRMS."Axys Analytical Services (proprietary).
3 "Working with Carcinogens," Department of Health, Education, & Welfare, Public
Health Service, Centers for Disease Control, NIOSH, Publication 77-206, August 1977,
NTIS PB-277256.
4 "OSHA Safety and Health Standards, General Industry," OSHA 2206, 29 CFR 1910.
5 "Safety in Academic Chemistry Laboratories," ACS Committee on Chemical Safety,
1979.
6 Provost, L.P., and Elder, R.S., "Interpretation of Percent Recovery Data," American
Laboratory, 15: 56-83, 1983.
7 " Standard Practice for Sampling Water," ASTM Annual Book of Standards, ASTM, 1916
Race Street, Philadelphia, PA 19103-1187, 1980.
9 "Handbook of Analytical Quality Control in Water and Wastewater Laboratories,"
USEPA EMSL, Cincinnati, OH 45268, EPA-600/4-79-019, March 1979.
10. Less is Better: Laboratory Chemical Management for Waste Reduction, available from
the American Chemical Society's Department of Governmental Relations and Science
Policy, 1155 16th Street NW, Washington DC 20036, 202/872-4477.
11. Environmental Management Guide for Small Laboratories (EPA 233-B-98-001).
12. The Waste Management Manual for Laboratory Personnel, available from the American
Chemical Society's Department of Government Relations and Science Policy, 1155 16th
Street NW, Washington, DC 20036, 202/872-4477.
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Method 1698
December 2007
23.0 Tables
Table 1. Names and CAS Registry Numbers for steroids and hormones determined by isotope dilution
and internal standard HRGC/HRMS
Steroid/hormone
Androstenedione
Androsterone
Campesterol
Cholestanol
Cholesterol
Coprostanol
Desmosterol
Desogestrel
17a-Dihydroequilin
Epi-Coprostanol
Equilenin
Equilin
Ergosterol
17ot-Estradiol
17ot-Ethynyl Estradiol
17p-Estradiol
p-Estradiol-3 -benzoate
Estriol
Estrone
Mestranol
Norethindrone
Norgestrel
Progesterone
beta-Sitosterol
beta-Stigmastanol
Stigmasterol
Testosterone
CAS#
63-05-8
53-41-8
474-62-4
80-97-7
57-88-5
360-68-9
313-04-2
54024-22-5
651-55-8
516-92-7
517-09-9
474-86-2
57-87-4
57-91-0
57-63-6
50-28-2
50-50-0
50-27-1
53-16-7
72-33-3
68-22-4
6533-00-2
57-83-0
83-46-5
83-45-4
83-48-7
58-22-0
Labeled analog
Bisphenol A propane-d6
Cholesterol-d7
Diethylstilbestrol-dg
17ot-Ethynyl Estradiol-d4
17(3-Estradiol-d4
Mestranol-d4
Norethindrone-de
Norgestrel-d6
Progesterone-d9
CAS#
49
-------
Method 1698
December 2007
Table 2. Retention times (RTs); relative retention times (RRTs); retention time and quantitation references; exact m/zs; theoretical m/z ratios;
method detection limits (MDLs); and minimum levels of quantitation (MLs), for the TMS derivatives of steroids and hormones
Ref
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Labeled injection internal
standard or steroid/
hormone (as TMS
derivative)
n-Octadecanol-d37 (6)
Pyrene-dio
Bisphenol A-propane-d6
Androsterone
Desogestrel
17a-Estradiol
Estrone
Androstenedione
Equilin
17p-Estradiol-d4
17|3-Estradiol
Testosterone
Equilenin
Mestranol-d4
Mestranol
Norethindrone-de
Norethindrone
17a-Dihydroequilin
17a-Ethynyl Estradiol-d4
17a-Ethynyl Estradiol
Progesterone-d9
Progesterone
Norgestrel-d6
Norgestrel
Estriol
Coprostanol
Epicoprostanol
Cholesterol-d7
RT
(sec) l
1055
1062
1104
1268
1286
1349
1354
1355
1359
1380
1382
1396
1425
1424
1427
1434
1438
1468
1476
1478
1496
1503
1535
1540
1577
1737
1745
1815
RRT2
0.993
.000
.040
.202
.219
.279
.283
.284
.288
.299
.001
.012
.351
.341
.002
.350
.003
0.995
.390
.001
.409
.005
.455
.003
.027
0.957
0.961
1.709
RT
window
(sec)3
20
100
20
6
6
6
6
6
6
20
6
8
8
20
6
20
6
6
20
6
20
6
20
6
6
6
6
20
RT
ref
Quant
ref
2| 2
self ref
2
1
1
1
1
1
1
2
10
10
1
2
14
2
16
19
2
19
2
21
2
23
23
28
28
2
2
10
10
10
10
10
1
2
10
10
1
2
14
2
16
19
2
19
2
21
2
23
23
28
28
2
Exact m/zs4
1
374.5405
213.1400
360.1894
347.2406
353.2300
416.2566
342.2015
286.1933
340.1858
420.2817
416.2566
360.2484
338.1702
371.2344
367.2093
361.2470
355.2093
307.1913
429.2583
425.2332
323.2811
314.2246
361.2470
355.2093
504.2910
370.3631
370.3631
375.3913
2
365.5439
214.0000
361.1927
348.2440
354.2334
417.2600
343.2048
287.1966
341.1892
421.2851
417.2600
361.2518
339.1739
372.2378
368.2127
362.2503
356.2127
308.1946
430.2616
426.2365
324.2844
315.2279
362.2503
356.2127
505.2944
371.3664
371.3664
376.3947
ml/m2
Theoreti-
cal ratio
4.50
5.62
2.90
3.44
3.21
2.67
3.45
4.73
3.46
2.67
2.67
3.32
3.46
3.21
3.21
3.32
3.31
3.39
2.59
2.59
3.09
4.44
3.32
3.32
2.17
3.18
3.18
3.18
Function
1
1
2
2
2
2
2
2
2
2
2
2
o
J
3
o
J
3
o
J
4
4
4
4
4
4
4
5
5
5
5
Detection lim
(]
Water
(ng/L)
MDL
0.3
0.3
0.1
0.2
0.3
0.1
0.1
0.7
0.1
0.1
0.1
0.2
0.1
2.1
0.1
0.1
1.3
0.7
ML
2
2
2
2
10
2
2
2
2
2
2
2
2
10
4
2
2
2
ts and minimum levels of
uantitation5
Other
(ng/kg)
MDL
30
30
10
20
30
10
10
70
10
10
10
20
10
21
10
10
130
70
ML
200
200
200
200
1000
200
200
200
200
200
200
200
200
1000
400
200
200
200
Extract
(pg/OL)
ML
2
2
2
2
10
2
2
2
2
2
2
2
2
10
4
2
2
2
-------
Method 1698
December 2007
Ref
29
30
31
32
33
34
35
36
37
Labeled injection internal
standard or steroid/
hormone (as TMS
derivative)
Cholesterol
Cholestanol
Desmosterol
Ergosterol
Campesterol
Stigmasterol
p-Sitosterol
(3-Stigmastanol
p-Estradiol-3 -benzoate
RT
(sec) 1
1821
1829
1851
1886
1901
1925
1974
1983
2186
RRT2
.003
.008
.020
.039
.047
.061
.088
.093
.424
RT
window
(sec)3
10
6
8
6
6
6
6
6
12
RT
ref
28
28
28
28
28
28
28
28
23
Quant
ref
28
28
28
28
28
28
28
28
23
Exact m/zs4
1
368.3474
445.3865
441.3552
363.3447
382.3631
484.4100
486.4257
488.4413
105.0340
2
369.3508
446.3899
442.3586
364.3475
383.3664
485.4134
487.4290
489.4447
106.0374
ml/m2
Theoreti-
cal ratio
3.18
2.62
2.90
3.08
3.08
1.94
2.41
2.41
12.72
Function
5
5
5
5
5
5
5
5
6
Detection limi
q
Water
(ng/L)
MDL
0.6 est
2.7
5.2
20 est
4.6
0.6 est
1.2 est
2.0 est
0.6
ML
10
10
20
50
10
2
6
6
2
ts and minimum levels of
uantitation5
Other
(ng/kg)
MDL
60 est
270
520
2000
460
60
120
200
60
ML
1000
1000
2000
5000
1000
200
500
500
200
Extract
(pg/OL)
ML
10
10
20
50
10
2
6
6
2
1 . Retention time of steroid/hormone or labeled compound.
2. Relative retention time (RRT) between the target and reference compound.
3 . RT limits based on estimated RRT variability.
4. Calculation of accurate masses monitored in this method is based on most abundant fragment ion for the predominant TMS derivative. Generally these
are M and M+l ions of the TMS ether molecular ions, but there are several exceptions.
5. Method detection limits (MDLs) and minimum levels of quantitation (MLs) with no interferences present.
6. Use Bisphenol A-propane-d6 as the internal standard if there is an interference with n-Octadecanol-d37
51
-------
Method 1698
December 2007
Table 2A. Formulas and quantitation m/zs for sterols and hormones analyzed as trimethylsilyl ethers
Compound
Desogestrel
17a-Estradiol
Estrone
Androsterone
Androstenedione
Equilin
17b-Estradiol
Testosterone
Equilenin
Mestranol
Norethindrone
1 7a-Dihy droequilin
Progesterone
1 7a-Ethny 1-Estradiol
Norgestrel
Estriol
Coprostanol
Epicoprostanol
Cholesterol
Cholestanol
Desmosterol
Ergosterol
Campesterol
Stigmasterol
b-Sitosterol
b-Stigmastanol
1 7a-Estradiol-3-Benzoate
Bisphenol A-propane-dg
17b-Estradiol-d4
Mestranol-d4
Norethindrone-dg
1 7a-Ethiny l-Estradiol-d4
Progesterone-dp
Norgestrel-d6
n-Octadecanol-d37
Cholesterol-d7
Formula of Parent
Compound
C22 H30 0
C18H24O2
C18H2202
C19H30O2
C19H2602
cis mo 02
C18H2402
C19H28O2
CIS HIS O2
C2i me 02
C20 me 02
CIS H22 02
C21 H30 O2
C20 H24 02
C21 H28 O2
C18H2403
C27 H48 0
C27 H48 O
C27 H46 0
C27 H48 O
C27 H44 0
C28 H44 O
C28 H48 0
C29 H48 O
C29 H50 O
C29 H52 0
C25 H28 O3
C15H10D602
cis mo D4 02
C21H22D402
C20 mo D6 02
C20 mo D4 02
C21 mi D9 O2
C21H24D6O2
C18HD370
C27 H39 D7 O
#TMS
Moieties in
Derivative
1
2
1
1
Type of Ion
Monitored
M -C2H5
M
M
M-CH3
Formula of Ion
Monitored
C23 H33 0 Si
C24 H40 O2 Si2
C21 H30 02 Si
C21 H35 O2 Si
Determine underivatized (1)
1
2
1
1
1
1
2
M
M
M
M
M-CH3
M-CH3
M-C8H9
C21 H28 O2 Si
C24 H40 02 Si2
C22 H36 O2 Si
C21 H26 O2 Si
C23 H31 02 Si
C22 H31 O2 Si
C16 H27 02 Si2
Determine underivatized ^
2
1
3
1
1
1
1
1
1
1
1
1
1
1
2
2
1
1
2
M-CH3
M-C2H5
M
M-C3 HI 0 0 Si
M-C3 H10 O Si
M-C3 HI 0 0 Si
M-CH3
M-CH3
M-C4H13OSi
M-C3 HI 0 0 Si
M
M
M
C7H5O
M-CD3
M
M-CH3
M-CH3
M-CH3
C25 H37 02 Si2
C22 H31 O2 Si
C27 H48 03 Si3
C27 H46
C27 H46
C27 H44
C29 H53 O Si
C29 H49 0 Si
C27 H39
C28 H46
C32 H56 O Si
C32 H58 O Si
C32 H60 0 Si
C7H5O
C20 H26 D6 O2 Si2
C24 H36 D4 O2 Si2
C23 H27 D4 O2 Si
C22 H25 D6 O2 Si
C25 H33 D4 O2 Si2
Determine underivatized ^
1
1
1
M-C2H5
M
M-C3 H10 O Si
C22 H25 D6 O2 Si
C21H10D370Si
C27 H37 D7
Masses Monitored
Ml
353.2300
416.2566
342.2015
347.2406
286.1933
340.1858
416.2566
360.2484
338.1702
367.2093
355.2093
307.1549
314.2246
425.2332
355.2093
504.2910
370.3600
370.3600
368.3443
445.3865
441.3552
363.3052
382.3600
484.4100
486.4257
488.4413
105.0340
360.1894
420.2817
371.2344
361.2470
429.2583
323.2811
361.2470
364.5405
375.3882
M2
354.2334
417.2600
343.2048
348.2440
287.1960
341.1892
417.2600
361.2518
339.1735
368.2127
356.2127
308.1583
315.2309
426.2365
356.2127
505.2944
371.3633
371.3633
369.3477
446.3899
442.3586
364.3085
383.3633
485.4134
487.4290
489.4447
106.0374
361.1927
421.2851
372.2378
362.2503
430.2616
324.2844
362.2503
365.5439
376.3916
1. The TMS derivatives of these compounds are unstable and decompose to their underivatized forms
52
-------
Method 1698
December 2007
Table 3. Suggested stock and spiking solution concentrations, and concentrations in final 500-|oL extract
Compound
Stock solution (ng/mL)1
Spiking solution (ng/mL)
Cone in extract (ng/mL)
Native compound solutions <2)
Desogestrel
17a-Estradiol
Estrone
Androsterone
Androstenedione
Equilin
17p-Estradiol
Testosterone
Equilenin
Mestranol
Norethindrone
1 7a-Dihy droequilin
Progesterone
1 7a-Ethyny 1-Estradiol
Norgestrel
Estriol
Coprostanol
Epicoprostanol
Cholesterol
Cholestanol
Desmosterol
Ergosterol
Campesterol
Stigmasterol
p-Sitosterol
p-Stigmastanol
p-Estradiol-3 -Benzoate
10
10
10
10
50
10
10
10
10
10
10
10
50
10
20
10
10
10
50
10
50
50
10
10
30
30
10
100
100
100
100
500
100
100
100
100
100
100
100
500
100
200
100
100
100
500
100
500
500
100
100
300
300
100
200
200
200
200
1000
200
200
200
200
200
200
200
1000
200
400
200
200
200
1000
200
1000
1000
200
200
600
600
200
Labeled compound solution <3)
n-Octadecanol-d37
Bisphenol A-propane-d6
17p-Estradiol-d4
Mestranol-d4
Norethindrone-d6
50
50
2.0
50
50
500
500
100
500
500
1000
1000
200
1000
1000
53
-------
Method 1698
December 2007
Compound
1 7a-Ethy nyl-Estradiol-d4
Progesterone-dg
Norgestrel-de
Cholesterol-d7
Stock solution (jig/mL)1
50
50
50
250
Spiking solution (ng/mL)
500
500
500
2500
Cone in extract (ng/mL)
1000
1000
1000
5000
Labeled cholesterol spiking solution for biosolids <4)
Cholesterol-d7
6000
60000
120000
Labeled injection internal standard solution (5)
Pyrene-d10
2.5
250
1 . Concentration of combined individual stock solutions (Section 7.9.1)
2. When 1 mL of the Native compound spiking solution is spiked into an IPR or OPR and concentrated to 500 uL,
or when 40 uL is spiked into an IPR or OPR and concentrated to 20 uL, the final extract concentrations will be
as shown in the last column.
When 1 mL of the Labeled compound spiking solution is spiked into a sample, IPR, OPR, or blank and
concentrated to 500 uL, or when 40 uL is spiked and concentrated to 20 uL, the final extract concentrations will
be as shown in the last column.
When 1 mL of this solution is spiked into a sample along with 1 mL of the labeled compound spiking solution,
and the sample extract is concentrated to 500 uL, the concentration of Cholesterol-d7 will be 125 ug/mL
(125,000 ng/mL), 25 times the nominal concentration. This solution is not spiked into a sample to be
concentrated to 20 uL, nor into an IPR, OPR, or blank.
When 50 uL of this solution is spiked into a 500 uL extract, or 2 uL is spiked into a 20 uL extract, the
concentration in the extract will be 250 ng/mL (250 pg/uL)
54
-------
Method 1698
December 2007
Table 4. Concentrations of steroids/hormones in calibration and calibration verification standards
Ratio between levels
Solution identifier
Solution concentration (ng/mL; pg/uL)
1
CS-0.2
5
CS-1
25
CS-2
100
CS-3
(VER) (1)
500
CS-4
2500
CS-5
Native (unlabeled) compounds
Desogestrel
17a-Estradiol
Estrone
Androsterone
Androstenedione
Equilin
17p-Estradiol
Testosterone
Equilenin
Mestranol
Norethindrone
17a-Dihydroequilin
Progesterone
1 7a-Ethyny 1-Estradiol
Norgestrel
Estriol
Coprostanol
Epicoprostanol
Cholesterol
Cholestanol
Desmosterol
Ergosterol
Campesterol
Stigmasterol
p-Sitosterol
p-Stigmastanol
p-Estradiol-3 -Benzoate
2.00
2.00
2.00
2.00
10.0
2.00
2.00
2.00
2.00
2.00
2.00
2.00
10.0
2.00
4.00
2.00
2.00
2.00
10.0
2.00
10.0
10.0
2.00
2.00
6.00
6.00
2.00
10.0
10.0
10.0
10.0
50.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
50.0
10.0
20.0
10.0
10.0
10.0
50.0
10.0
50.0
50.0
10.0
10.0
30.0
30.0
10.0
50.0
50.0
50.0
50.0
250.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
250
50.0
100
50.0
50.0
50.0
250
50.0
250
250
50.0
50.0
150
150
50.0
200
200
200
200
1000
200
200
200
200
200
200
200
1000
200
400
200
200
200
1000
200
1000
1000
200
200
600
600
200
1000
1000
1000
1000
5000
1000
1000
1000
1000
1000
1000
1000
5000
1000
2000
1000
1000
1000
5000
1000
5000
5000
1000
1000
3000
3000
1000
5000
5000
5000
5000
25000
5000
5000
5000
5000
5000
5000
5000
25000
5000
10000
5000
5000
5000
25000
5000
25000
25000
5000
5000
15000
15000
5000
Labeled compounds
17p-Estradiol-d4
Mestranol-d4
Norethindrone-de
200
1000
1000
200
1000
1000
200
1000
1000
200
1000
1000
200
1000
1000
200
1000
1000
55
-------
Method 1698
December 2007
1 7a-Ethy nyl-Estradiol-cL,
Progesterone-dg
Norgestrel-de
Bisphenol A-propaned6
n-Octadecanol-d37
Cholesterol-d7(2)
Pyrene-dio
1000
1000
1000
1000
1000
5000
250
1000
1000
1000
1000
1000
5000
250
1000
1000
1000
1000
1000
5000
250
1000
1000
1000
1000
1000
5000
250
1000
1000
1000
1000
1000
5000
250
1000
1000
1000
1000
1000
5000
250
1. Calibration verification
2. Cholesterol-d7 is spiked at 120 ug/mL (120,000 ng/mL) inbiosolids and other samples expected to contain high
levels of cholesterol.
56
-------
Method 1698
December 2007
Table 5. QC acceptance criteria for steroids and hormones in VER, IPR, OPR, and samples.
Steroid/Hormone
VER (%)
IPR
X (%)
RSD (%)
OPR (%)
Labeled compound
recovery in samples
Native compounds
Androstenedione
Androsterone
Campesterol
Cholestanol
Cholesterol
Coprostanol
Desmosterol
Desogestrel
1 7a-Dihy droequilin
Epi-Coprostanol
Equilenin
Equilin
Ergosterol
17a-Estradiol
17a-Ethynyl Estradiol
17p-Estradiol
p-Estradiol-3 -benzoate
Estriol
Estrone
Mestranol
Norethindrone
Norgestrel
Progesterone
p-Sitosterol
p-Stigmastanol
Stigmasterol
Testosterone
70-130
70 - 130
70-130
70-130
70 - 130
70-130
70 - 130
70-130
70 - 130
70-130
70 - 130
65-135
50-150
70 - 130
70 - 130
70 - 130
70-130
70 - 130
70-130
70-130
70 - 130
70-130
70-130
70-130
70 - 130
70-130
70-130
6-180
55 - 109
44 - 180
55 - 148
6-180
37-180
6-180
55 - 108
49-136
55 - 177
6-180
6-180
6-180
55 - 108
55-110
55-158
6-170
6-173
55-155
55 - 108
50 - 180
50 - 180
6-180
6-180
32 - 180
55 - 180
55-123
59
30
30
30
71
30
30
30
30
30
106
95
58
30
30
30
128
49
30
30
38
36
153
74
30
30
30
5-200
50-121
40 - 200
50 - 164
5-200
34 - 200
5-200
50 - 120
45-151
50-197
5-200
5-200
5-200
50 - 120
50-123
50 - 176
5-189
5-193
50-173
50 - 120
45 - 200
46 - 200
5-200
5-200
29 - 200
50 - 200
50-136
Labeled compounds
Cholesterol-d7
17a-Ethynyl Estradiol-d4
17p-Estradiol-d4
Mestranol-d4
70 - 130
70 - 130
70-130
70 - 130
55 - 108
55 - 108
55 - 108
55 - 108
30
30
30
30
50 - 120
50 - 120
50 - 120
50 - 120
50 - 120
50 - 120
29-132
50 - 120
57
-------
Method 1698
December 2007
Steroid/Hormone
Norethindrone-de
Norgestrel-ds
Progesterone-d9
VER (%)
70 - 130
70 - 130
70-130
IPR
X (%)
40 - 108
40 - 108
6-180
RSD (%)
30
30
73
OPR (%)
37-120
36-120
5-200
Labeled compound
recovery in samples
12 - 120
7-120
5-200
58
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Method 1698
December 2007
Table 6. Suggested sample quantities to be extracted for various matrices'
Sample matrix
Example Matrix Type
Percent
solids
Phase
Quantity extracted
Single-phase
Aqueous
Solid
Drinking water
Groundwater
Treated wastewater
Dry soil
Compost
<1
>20
Liquid
Solid
1000 mL
10 g
Multi-phase
Aqueous/solid
Wet soil
Untreated effluent
Biosolids (municipal sludge)
1 20
>5
Both
Solid
lOOOmLor 10 g of solids
0.25 g
1. The quantity of sample to be extracted is adjusted to provide 10 g dry weight of solids (0.25 g for biosolids).
One liter of an aqueous sample containing 1% solids will contain 10 g of solids. For an aqueous sample
containing greater than 1% solids, a lesser volume is used so that 10 g dry weight of solids will be prepared.
Table 7. Performance Data from single laboratory validation.
59
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Method 1698
December 2007
Desogestrel
17a-Estradiol
Estrone
Androstenone
Androstenedione
Equilin
17b-Estradiol
Testosterone
Equilenin
Mestranol
Norethindrone
1 7a-Dihydroequilin-bis
Progesterone
17a-Ethynyl-Estradiol
Norgestrel
Estriol-tris
Coprostanol
Epicoprostanol
Cholesterol
Cholestanol
Desmosterol
Ergosterol
Campesterol
Stigmasterol
b-Sitosterol
b-Stigmastanol
b-Estradiol-3-Benzoate
d6-Bisphenol-a-propane
d8-diethylstilbesterol
d4-Equilin
d4-17b-Estradiol
d4-Mestranol
d6-Norethindrone
d4-17a-Ethynyl-Estradiol
d9-Progesterone
d6-Norgestrel
d7-Cholesterol
Biosolids-Based on 2 samples
Biosolids
Average
Recovery
212.63
195.39
243.71
85.28
179.66
23.52
73.24
32.23
109.98
94.97
104.06
168.94
176.87
100.82
101.60
1 84.60
*
*
*
*
*
*
*
*
*
*
1 94.45
76.65
56.18
86.10
58.80
76.65
60.38
82.95
129.15
61.95
89.58
Biosolids
Standard
Deviation
15.05
17.45
67.16
9.22
61.61
11.56
3.58
5.07
9.19
1.94
50.40
16.41
55.04
3.02
13.43
53.91
*
*
*
*
*
*
*
*
*
*
41.50
3.64
2.01
24.79
7.07
4.37
15.08
5.56
53.61
16.93
6.86
Biosolids
Relative
Standard
Deviation
7.08
8.93
27.56
10.81
34.29
49.15
4.89
15.72
8.36
2.04
48.43
9.71
31.12
3.00
13.21
29.20
*
*
*
*
*
*
*
*
*
*
21.34
4.75
3.58
28.79
12.02
5.70
24.98
6.70
41.51
27.33
7.66
Solid-Based on 4 samples
Solids
Average
Recovery
85.07
88.23
103.79
107.04
142.25
210.68
128.60
94.68
152.30
102.07
123.13
81.19
149.93
98.71
118.36
111.14
89.93
95.67
297.43
102.03
28.36
*
95.50
114.75
203.53
103.19
50.67
79.54
13.74
31.28
86.02
84.70
56.38
78.66
88.34
57.46
92.66
Solids
Standard
Deviation
3.44
3.18
7.17
4.87
40.84
33.47
10.33
4.22
11.95
1.44
6.78
6.91
10.71
1.29
6.37
20.62
4.44
1.92
109.48
5.72
6.65
*
6.11
16.46
90.81
7.98
22.69
6.12
2.22
1.86
2.41
2.22
5.15
4.10
35.57
5.56
3.54
Solids
Relative
Standard
Deviation
4.04
3.61
6.91
4.55
28.71
15.89
8.03
4.46
7.85
1.41
5.51
8.51
7.15
1.31
5.38
18.55
4.93
2.00
36.81
5.61
23.44
*
6.40
14.34
44.62
7.73
44.77
7.70
16.13
5.94
2.80
2.62
9.14
5.21
40.26
9.67
3.82
Reagent Water-Based on 6 samples
Water
Average
Recovery
79.44
102.46
134.07
108.42
60.72
154.16
139.75
114.27
179.13
108.01
158.91
111.59
271 .70
111.04
155.36
23.00
157.29
147.77
136.96
133.35
152.83
138.13
161.93
1 64.65
275.05
191.00
68.91
70.33
31.63
56.67
99.57
80.88
49.68
71.02
28.98
42.03
74.27
Water
Standard
Deviation
0.10
0.02
0.12
0.04
0.13
1.15
0.14
0.06
1.29
0.01
0.36
0.13
2.26
0.01
0.33
0.09
0.04
0.07
0.12
0.03
0.04
0.43
0.05
0.12
0.89
0.07
0.51
8.69
8.29
22.73
11.91
9.88
18.80
10.74
15.90
16.72
8.13
Water
Relative
Standard
Deviation
0.13
0.01
0.09
0.03
0.21
0.75
0.10
0.05
0.72
0.01
0.22
0.11
0.83
0.01
0.21
0.40
0.02
0.05
0.09
0.03
0.02
0.31
0.03
0.07
0.32
0.04
0.75
12.36
26.22
40.10
11.96
12.21
37.85
15.13
54.87
39.77
10.95
Note: For biosolids recoveries * indicates that compounds were found in high concentrations in
biosolids samples, rendering MS/MSD results unreliable.
60
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Method 1698
December 2007
24.0 Glossary
These definitions and purposes are specific to this method but have been conformed to common usage to
the extent possible.
24.1 Units of weight and measure and their abbreviations
24.1.1 Symbols
EC degrees Celsius
|oL microliter
jam micrometer
< less than
> greater than
% percent
24.1.2 Alphabetical abbreviations
cm centimeter
g gram
h hour
ID inside diameter
in. inch
L liter
M Molecular ion
m mass or meter
mg milligram
min minute
mL milliliter
mm millimeter
m/z mass-to-charge ratio
N normal; gram molecular weight of solute divided by hydrogen equivalent
of solute, per liter of solution
OD outside diameter
pg picogram
ppb part-per-billion
ppm part-per-million
ppq part-per-quadrillion
ppt part-per-trillion
psig pounds-per-square inch gauge
v/v volume per unit volume
w/v weight per unit volume
61
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Method 1698 December 2007
25.0 Definitions and Acronyms
Analyte - A steroid or hormone tested for by this method. The analytes are listed in Table 1.
Calibration standard (CAL) - A solution prepared from a secondary standard and/or stock solution
and used to calibrate the response of the HRGC/HRMS instrument.
Calibration verification standard (VER) - The mid-point calibration standard (CS-3) that is used to
verify calibration. See Table 4.
CS-0.2, CS-1, CS-2, CS-3, CS-4, CS-5 - See Calibration standards and Table 4.
Field blank - An aliquot of reagent water or other reference matrix that is placed in a sample
container in the field, and treated as a sample in all respects, including exposure to sampling site
conditions, storage, preservation, and all analytical procedures. The purpose of the field blank is to
determine if the field or sample transporting procedures and environments have contaminated the
sample.
GC - Gas chromatograph or gas chromatography
HRGC - High resolution GC
HRMS - High resolution MS
Labeled injection internal standard - Labeled pyrene (di0) is spiked into the concentrated extract
immediately prior to injection of an aliquot of the extract into the HRGC/HRMS.
Internal standard - A labeled compound used as a reference for quantitation of other labeled
compounds and for quantitation of steroids and hormones other than the steroid or hormone of which
it is a labeled analog. See internal standard quantitation.
Internal standard quantitation - A means of determining the concentration of (1) a naturally
occurring (native) compound by reference to a compound other than its labeled analog and (2) a
labeled compound by reference to the labeled injection internal standard.
IPR - Initial precision and recovery; four aliquots of a reference matrix spiked with the analytes of
interest and labeled compounds and analyzed to establish the ability of the laboratory to generate
acceptable precision and recovery. An IPR is performed prior to the first time this method is used and
any time the method or instrumentation is modified.
Isotope dilution quantitation - A means of determining a naturally occurring (native) compound by
reference to the same compound in which one or more atoms has been isotopically enriched. In this
method, labeled compounds are enriched with deuterium and/or 13C to produce deuterium- and/or
13C-labeled analogs. The labeled compounds are spiked into each sample to allow identification and
correction of the concentration of the native compounds in the analytical process.
KD - Kuderna-Danish concentrator: a device used to concentrate the analytes in a solvent
62
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Method 1698 December 2007
Laboratory blank - See method blank
Laboratory control sample (LCS) - See Ongoing precision and recovery standard (OPR)
Laboratory reagent blank - See method blank
May - This action, activity, or procedural step is neither required nor prohibited.
May not - This action, activity, or procedural step is prohibited.
Method blank - An aliquot of reagent water that is treated exactly as a sample including exposure to
all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with
samples. The method blank is used to determine if analytes or interferences are present in the
laboratory environment, the reagents, or the apparatus.
Method detection limit (MDL) - The lowest concentration at which a steroid or hormone can be
detected under routine operating conditions (see 40 CFR 136, appendix B). MDLs are listed in Table
2.
Minimum level (ML) - This is the greater of a multiple of the MDL or the lowest calibration point
(see 68 FR 11790, March 12, 2003.) MLs are listed in Tables 2.
MS - Mass spectrometer or mass spectrometry
Must - This action, activity, or procedural step is required.
OPR - Ongoing precision and recovery standard (OPR), also known as a laboratory control sample
(LCS): a method blank spiked with known quantities of analytes. The OPR is analyzed exactly like a
sample. Its purpose is to assure that the results produced by the laboratory remain within the limits
specified in this method for precision and recovery.
Perfluorokerosene (PFK) - A mixture of compounds used to calibrate the exact m/z scale in the
HRMS.
Preparation blank - See method blank
Quality control check sample (QCS) - A sample containing all or a subset of the analytes at known
concentrations. The QCS is obtained from a source external to the laboratory or is prepared from a
source of standards different from the source of calibration standards. It is used to check laboratory
performance with test materials prepared external to the normal preparation process.
Reagent water - Water demonstrated to be free from the analytes of interest and potentially
interfering substances at the method detection limit for the analyte.
Relative standard deviation (RSD) - The standard deviation times 100 divided by the mean. Also
termed "coefficient of variation."
RF - Response factor. See Section 10.5
63
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Method 1698 December 2007
RR - Relative response. See Section 10.4
RSD - See relative standard deviation
Signal-to-noise ratio (S/N) - The height of the signal as measured from the mean (average) of the
noise to the peak maximum divided by the width of the noise.
Should - Although, this action, activity, or procedural step is suggested and not required, you may be
asked to explain why you changed or omitted this action, activity, or procedural step.
SICP - Selected ion current profile; the line described by the signal at an exact m/z.
Specificity (also known as selectivity) - the ability of an analytical method to determine the
presence and concentration of an analyte in the presence of interferences and other analytes in the
method.
Stock solution - A solution containing an analyte that is prepared using a reference material
traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will attest
to the purity and authenticity of the reference material.
Unique GC resolution or uniquely resolved - Two adjacent chromatographic peaks in which the
height of the valley is less than 20 percent of the height of the shorter peak (see Section 6.9.1.1.2).
VER - See calibration verification.
64
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