Unitad States Office of Water EPA-B21-R-04-D01
Environmental Protection (4303)
Agency January 2004
Method OlA-1677, DW
Available Cyanide by Fiow
Injection, Ligand Exchange,
and Amperometry
-------
Method OIA-1677, DW
Acknowledgments
This method was developed by Michael Straka of OI Analytical in cooperation with Emil
Milosavljevic and Ljiljana Solujic of the University of Nevada Reno Mackay School of Mines and
guidance from William A. Telliard of the Engineering and Analysis Division (BAD) within the U.S.
Environmental Protection Agency's (EPA's) Office of Science and Technology (OST). Additional
assistance in preparing the method was provided by DynCorp Information and Enterprise
Technology and Interface, Inc..
Disclaimer
This Method has been reviewed and approved for publication by the Analytical Methods Staff within
EPA's Engineering and Analysis Division. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
Questions concerning this Method or its application should be addressed to:
W.A. Telliard
Engineering and Analysis Division (4303)
U.S. Environmental Protection Agency
Ariel Rios Building
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460
Phone: 202/566-1061
Fax: 202/566-1053
January 2004
-------
Method OIA-1677, DW
Table of Contents
Introduction iv
1.0 Scope and Application 1
2.0 Summary of Method .1
3.0 Definitions 2
4.0 Contamination and Interferences 2
5.0 Safety 3
6.0 Equipment and Supplies 4
7.0 Reagents and Standards 4
8.0 Sample Collection, Preservation, and Storage 8
9.0 Quality Control 10
10.0 Calibration and Standardization 15
11.0 Procedure 16
12.0 Data Analysis and Calculations 16
13.0 Method Performance .17
14.0 Pollution Prevention and Waste Management 17
15.0 References 18
16.0 Tables 19
17.0 Glossary 20
January 2004
-------
Method OIA-1677, DW
Introduction
Method OIA-1677 was developed by ALPKEM, a division of OI Analytical, in cooperation with the
University of Nevada Reno Mackay School of Mines, as a way to measure available cyanide without the
interference problems of the currently approved available cyanide methods. EPA proposed the use of
Method OIA-1677 on July 7, 1998 (63 FR 36809). EPA is approving the use of Method OIA-1677 for
compliance monitoring under Section 304(h) of the Clean Water Act. Method OIA-1677 is an additional
test procedure for measuring the same cyanide species as are measured by currently approved methods
for cyanide amenable to chlorination (CATC). In some matrices, CATC methods are subject to
significant test interferences. Method OIA-1677 has been added to the list of approved methods because
it is more specific for available cyanide, is more rapid, measures cyanide at lower concentrations, offers
improved safety, reduces laboratory waste, and is more precise and accurate than currently approved
CATC methods.
iv January 2004
-------
Method OIA-1677
Available Cyanide by Flow Injection, Ligand Exchange, and
Amperometry
LOScope and Application
1.1 This method is for determination of available cyanide in water and wastewater by flow
injection, ligand exchange, and amperometric detection. The method is for use in EPA's
data gathering and monitoring programs associated with the Clean Water Act, Resource
Conservation and Recovery Act, Comprehensive Environmental Response,
Compensation and Liability Act, and Safe Drinking Water Act.
1.2 Cyanide ion (CN~), hydrogen cyanide in water (HCNaq), and the cyano-complexes of
zinc, copper, cadmium, mercury, nickel, and silver may be determined by this method
(see Section 17.2.1).
1.3 The presence of polysulfides may prove intractable for application of this method.
1.4 The method detection limit (MDL) is 0.5 ug/L and the minimum level (ML) is 2.0 |ig/L.
The dynamic range is approximately 2.0 |ag/L (ppb) to 5.0 mg/L (ppm) cyanide ion using
a 200 fjiL sample loop volume. Higher concentrations can be determined by dilution of
the original sample or by reducing volume of the sample loop.
1.5 This method is for use by analysts experienced with flow injection equipment or under
close supervision of such qualified persons.
2.0Summary of Method
2.1 The analytical procedure employed for determination of available cyanide is divided into
two parts: sample pretreatment and cyanide detection. In the pretreatment step, ligand-
exchange reagents are added at room temperature to 100 mL of a cyanide-containing
sample. The ligand-exchange reagents form thermodynamically stable complexes with
the transition metal ions listed in Section 1.2, resulting in the release of cyanide ion from
the metal-cyano complexes.
Cyanide detection is accomplished using a flow-injection analysis (FLA) system
(Reference 15.6). A 200-jnL aliquot of the pre-treated sample is injected into the flow
injection manifold of the system. The addition of hydrochloric acid converts cyanide ion
to hydrogen cyanide (HCN) that passes under a gas diffusion membrane. The HCN
diffuses through the membrane into an alkaline receiving solution where it is converted
back to cyanide ion. The cyanide ion is monitored amperometrically with a silver
working electrode, silver/silver chloride reference electrode, and platinum/stainless steel
counter electrode, at an applied potential of zero volt. The current generated is
proportional to the cyanide concentration present in the original sample. Total analysis
time is approximately two minutes.
January 2004
-------
Method OIA-1677, DW
2.2 The quality of the analysis is assured through reproducible calibration and testing of the
FIA system.
2.3 A flow diagram of the FIA system is shown in Figure 1.
Acceptor
Carrier
Add
Pump
Mbdng
Coll Diffusion
Call
Figure 1. Row injection Manifold used In the quantification of
cyanide in the pretreated sample. Carrier (0.1 M
HO); Add (0.1 M HCI); Acceptor (0.1 M NaOH).
S.ODefinitions
Definitions for terms used in this method are given in the glossary at the end of the
method.
4.0lnterferences
4.1 Solvents, reagents, glassware, and other sample-processing hardware may yield artifacts
that affect results. Specific selection of reagents or purification of these reagents may be
required.
4.2 All materials used in the analysis shall be demonstrated to be free from interferences
under the conditions of analysis by running laboratory blanks as described in Section 9.4.
4.3 Glassware is cleaned by washing in hot water containing detergent, rinsing with tap and
reagent water, and drying in an area free from interferences.
4.4 Interferences extracted from samples will vary considerably from source to source,
depending upon the diversity of the site being sampled.
4.5 Sulfide is a positive interferent in this method (References 15.3 and 15.4), because an
acidified sample containing sulfide liberates hydrogen sulfide that is passed through the
membrane and produces a signal at the silver electrode. In addition, sulfide ion reacts
with cyanide ion in solution to reduce its concentration over time. To overcome this
interference, the sulfide ion must be precipitated with lead ion immediately upon sample
collection. Sulfide ion and lead sulfide react with cyanide ion to form thiocyanate which
2 January 2004
-------
Method OIA-1677, DW
is not detected in the analytical system. Tests have shown (Reference 15.7) that if lead
carbonate is used for sulfide precipitation, the supemate containing cyanide must be
filtered immediately to avoid loss of cyanide through reaction with precipitated lead
sulfide (Section 8.2.1).
4.6 Though not interferences, substances that react with cyanide should also be removed from
samples at time of collection. These substances include water soluble aldehydes that
form cyanohydrins and oxidants such as hypochlorite and sulfite. Water soluble
aldehydes react with cyanide to form cyanohydrins that are not detected by the analytical
system; hypochlorite and sulfite oxidize cyanide to non-volatile forms. Procedures for
the removal of these substances are provided in Sections 8.2.2 and 8.2.3.
S.OSafety
5.1 The toxicity or carcinogenicity of each compound or reagent used in this method has not
been precisely determined; however, each chemical compound should be treated as a
potential health hazard. Exposure to these compounds should be reduced to the lowest
possible level.
5.2 Cyanides and cyanide solutions
WARNING: The cyanide ion, hydrocyanic acid, all cyanide salts, and
most metal-cyanide complexes are extremely dangerous. As a contact
poison, cyanide need not be ingested to produce toxicity. Also,
cyanide solutions produce fatally toxic hydrogen cyanide gas when
acidified. For these reasons, it is mandatory that work with cyanide
be carried out in a well-ventilated hood by properly trained personnel
wearing adequate protective equipment.
5.3 Sodium hydroxide solutions
CAUTION: Considerable heat is generated upon dissolution of sodium
hydroxide in water. It may be advisable to cool the container in an
ice bath when preparing sodium hydroxide solutions.
5.4 Unknown samples may contain high concentrations of volatile toxic compounds. Sample
containers should be opened in a hood and handled with gloves to prevent exposure.
5.5 This method does not address all safety issues associated with its use. The laboratory is
responsible for maintaining a safe work environment and 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 be available to all
personnel involved in these analyses. Additional information on laboratory safety can be
found in References 15.8 and 15.9.
January 2004
-------
Method OIA-1677, DW
G.OEquipment and Supplies
NOTE: Brand names, suppliers, and part numbers are for illustrative
purposes only. No endorsement is implied. Equivalent performance may
be achieved using apparatus and materials other than those specified
here, but demonstration of equivalent performance that meets the
requirements of this method is the responsibility of the laboratory.
6.1 Flow injection analysis (HA) system—ALPKEM Model 3000 (Reference 15.5), or
equivalent, consisting of the following:
6.1.1 Injection valve capable of injecting 40 to 300 fJiL samples
6.1.2 Gas diffusion manifold with a microporous Teflon® or polypropylene membrane
6.1.3 Amperometric detection system with:
6.1.3.1 Silver working electrode
6.1.3.2 Ag/AgCl reference electrode
6.1.3.3 Pt/stainless steel counter electrode
6.1.3.4 Applied potential of 0.0 volt
6.2 Sampling equipment—Sample bottle, amber glass, 0.1-L, with polytetrafluoroethylene
(PTFE)-lined cap. Clean by washing with detergent and water, rinsing with two aliquots
of reagent water, and drying by baking at 110 -150 °C for one hour minimum.
6.3 Standard laboratory equipment including volumetric flasks, pipettes, syringes, etc. all
cleaned, rinsed and dried per bottle cleaning procedure in Section 6.2.
7.0Reagents and Standards
7.1 Reagent water—Water in which cyanide and potentially interfering substances are not
detected at the MDL of this method. It may be generated by any one of the methods listed
below. Reagent water generated by these methods shall be tested for purity utilizing the
procedure in Section 11.
7.1.1 Activated carbon—Pass distilled or deionized water through an activated carbon
bed (Calgon Filtrasorb-300 or equivalent).
7.1.2 Water purifier—Pass distilled or deionized water through a purifier (Millipore
Super Q, or equivalent).
7.2 Sodium hydroxide—ACS reagent grade.
7.3 Potassium cyanide—ACS reagent grade.
4 January 2004
-------
Method OIA-1677, DW
7.4 Mercury (II) cyanide, ^99% purity—Aldrich Chemical Company Catalog No. 208140, or
equivalent.
7.5 Potassium nickel (II) cyanide—Aldrich Chemical Company Catalog No. 415154, or
equivalent.
7.6 Silver nitrate—ACS reagent grade. Aldrich Chemical Company Catalog No. 209139, or
equivalent.
7.7 Hydrochloric acid—approximately 37%, ACS reagent grade.
7.8 Preparation of stock solutions. Observe the warning in Section 5.2.
7.8.1 Silver nitrate solution, 0.0192 N—Weigh 3.27 g of AgNO3 into a 1-L volumetric
flask and bring to the mark with reagent water.
7.8.2 Rhodanine solution, 0.2 mg/mL in acetone—Weigh 20 mg of p-
dimethylaminobenzalrhodanine (Aldrich Chemical Co. Catalog No. 114588, or
equivalent) in a 100-mL volumetric flask and dilute to the mark with acetone.
7.8.3 Potassium cyanide stock solution, 1000 mg/L
7.8.3.1 Dissolve approximately 2 g (approximately 20 pellets) of sodium
hydroxide in approximately 500 mL of reagent water contained in a one
liter volumetric flask. Observe the caution in Section 5.3. Add 2.51 g of
potassium cyanide (Aldrich Chemical Co. Catalog No. 207810, or
equivalent), dilute to one liter with reagent water, and mix well. Store
KCN solution in an amber glass container at 0-4°C.
7.8.3.2 Standardize the KCN solution (Section 7.8.3.1) by adding 0.5 mL of
rhodanine solution (Section 7.8.2) to 25 mL of KCN solution and
titrating with AgNO3 solution (Section 7.8.1) until the color changes
from canary yellow to a salmon hue. Based on the determined KCN
concentration, dilute the KCN solution to an appropriate volume so the
final concentration is 1.00 g/L, using the following equation:
January 2004
-------
Method OIA-1677, DW
EQUATION 1
x * v = 1 g/L x l
x=concentration ofKCN solution determined from titrations
v=volume ofKCN solution needed to prepare 1 L of 1 g/L KCN solution
January 2004
-------
Method OIA-1677, DW
If the concentration is not 1.00 g/L, correct the intermediate and working
calibration concentrations accordingly.
7.8.4 1M sodium hydroxide—Dissolve 40 g of sodium hydroxide pellets in
approximately 500 mL of reagent water in a 1-liter volumetric flask, observing the
caution in Section 5.3. Dilute to one liter with reagent water. Store in an amber
bottle at room temperature.
7.9 Secondary standards.
7.9.1 Cyanide, 100 mg/L—Dilute 100.0 mL of cyanide stock solution (Section 7.8.3.2)
and 10 mL of 1M sodium hydroxide (Section 7.8.4) to one liter with reagent water
(Section 7.1). Store in an amber glass bottle at 0-4°C.
7.9.2 Cyanide, 10 mg/L—Dilute 10.0 mL of cyanide stock solution and 10 mL of 1M
sodium hydroxide to one liter with reagent water. Store in an amber glass bottle
at 0-4°C.
7.9.3 Cyanide, 1 mg/L—Dilute 1.0 mL of cyanide stock solution and 1 mL of 1M
sodium hydroxide to one liter with reagent water. Store in an amber glass bottle
at 0-4°C.
7.9.4 Cyanide working calibration standard solutions (2 - 5000 |ig/L as
cyanide)—Working calibration standards may be prepared to cover the desired
calibration range by adding the appropriate volumes of secondary standards
(Sections 7.9.1, 7.9.2, 7.9.3) to 100 mL volumetric flasks that contain 40 mL of
reagent water (Section 7.1) and 1 mL of 1M sodium hydroxide (Section 7.8.4).
Dilute the solutions to 100 mL with reagent water. Prepare working calibration
standards daily. The following table provides the quantity of secondary standard
necessary to prepare working standards of the specified concentration.
January 2004
-------
Method OIA-1677, DW
Working
Calibration
Standard
Concentration
G"g/L)
0.000
2.0
5.0
10.0
50.0
100
200
500
1000
3000
5000
Secondary Standard Solution Volume
Secondary Standard
Concentration
(Section 7.8.3)
Img/L
0.200
0.500
1.00
5.00
10.0
20.0
50.0
Secondary Standard
Concentration
(Section 7.8.2)
lOmg/L
0.050
0.100
0.500
1.00
2.00
5.00
10.0
30.0
50.0
Secondary Standard
Concentration
(Section 7.8.1)
lOOmg/L
0.050
0.100
0.200
0.500
1.00
3.00
5.00
If desired, the laboratory may extend the analytical working range by using standards that
cover more than one calibration range, so long as the requirements of Section 10.3 are
met.
7.10 Sample Preservation Reagents
7.10.1 The presence of sulfide may result in the conversion of cyanide to thiocyanate.
While lead acetate test paper has been recommended for determining the presence
of sulfide in samples, the test is generally unreliable and is typically not usable for
sulfide concentrations below approximately 1 ppm. The use of lead carbonate
(Aldrich Chemical Co. Catalog No. 336378, or equivalent), followed by
immediate filtration of the sample is required whenever sulfide ion is present. If
the presence of sulfide is suspected but not verifiable from the use of lead acetate
test paper, two samples may be collected, one without lead carbonate addition and
another with lead carbonate addition followed by immediate filtration. Analyze
both samples. If sulfide is present, the preserved sample should contain higher
levels of cyanide than the unpreserved sample. Lead acetate test paper may be
used, but should be tested for minimum level of sulfide detection by spiking
reagent water aliquots with decreasing levels of sulfide and determining the
lowest level of sulfide detection attainable. The spiked samples are tested with
lead acetate test paper moistened with acetate buffer solution. The buffer solution
8 January 2004
-------
Method OIA-1677, DW
is prepared by dissolving 146 g anhydrous sodium acetate, or 243 g sodium
acetate trihydrate in 400 mL of reagent water, followed by addition of 480 g
concentrated acetic acid. Dilute the solution to 1 L with reagent water. Each new
batch of test paper and/or acetate buffer should be tested to determine the lowest
level of sulfide ion detection prior to use.
7.10.2 Ethylenediamine solution—In a 100 mL volumetric flask, dilute 3.5 mL
pharmaceutical-grade anhydrous ethylenediamine (Aldrich Chemical Co. Catalog
No. 240729, or equivalent) with reagent water.
7.10.3 Ascorbic acid—Crystals—Aldrich Chemical Co. Catalog No. 268550, or
equivalent.
7.11 FIA Reagents.
7.11.1 Carrier and acid reagent (0.1M hydrochloric acid)—Dilute 8 mL of concentrated
hydrochloric acid to one liter with reagent water.
7.11.2 Acceptor reagent (0.1M sodium hydroxide)—Dilute 100 mL of sodium hydroxide
solution (Section 7.8.4) to 1000 mL with reagent water.
7.11.3 Ligand-exchange reagent A-ALPKEM part number A001416, or equivalent.
7.11.4 Ligand-exchange reagent B-ALPKEM part number A001417, or equivalent.
7.12 Quality control solutions
7.12.1 Mercury (II) cyanide stock solution (1000 mg/L as cyanide)—Weigh 0.486 g of
mercury (II) cyanide (Section 7.4) in a 100-mL volumetric flask. Add 10 - 20 mL
of reagent water and 1 mL of 1M sodium hydroxide solution (Section 7.8.4).
Swirl to mix. Dilute to the mark with reagent water.
7.12.2 Laboratory control sample (LCS)—Place 0.20 mL of the mercury (II) cyanide
stock solution (Section 7.12.1) in a 100-mL volumetric flask and dilute to the
mark with reagent water to provide a final cyanide concentration of 2.00 mg/L.
S.OSample Collection, Preservation, and Storage
8.1 Sample collection and preservation—Samples are collected using manual (grab)
techniques and are preserved immediately upon collection.
8.1.1 Grab sampling—Collect samples in amber glass bottles with PTFE-lined caps
cleaned according to the procedure in Section 6.2. Immediately after collection,
preserve the sample using any or all of the preservation techniques (Section 8.2),
followed by adjustment of the sample pH to > 12 by addition of 1M sodium
hydroxide and refrigeration at 0-4°C.
January 2004
-------
Method OIA-1677, DW
8.1.2 Compositing—Compositing is performed by combining aliquots of grab samples
only. Automated compositing equipment may not be used because cyanide may
react or degrade during the sampling period. Preserve and refrigerate each grab
sample immediately after collection (Sections 8.1.1 and 8.2) until compositing.
8.1.3 Shipment—If the sample will be shipped by common carrier or mail, limit the pH
to a range of 12.0 -12.3. (See the footnote to 40 CFR 136.3(e), Table E, for the
column headed "Preservation.")
8.2 Preservation techniques
8.2.1 Samples containing sulfide ion
8.2.1.1 Test the sample with lead acetate test paper (Section 7.10.1) to determine
the presence or absence of sulfide ion. If sulfide ion is present, the
sample must be treated immediately (within 15 minutes of collection)
with sufficient solid lead carbonate (Section 7.10.1) to remove sulfide
(as evidenced by the lead acetate test paper), and immediately filtered
into another sample bottle to remove precipitated lead sulfide.
8.2.1.2 If sulfide ion is suspected to be present, but its presence is not detected
by the lead acetate paper test, two samples should be collected. One is
treated for the presence of sulfide and immediately filtered, while the
second is not treated for sulfide. Both samples must be analyzed. (Tests
conducted prior to the interlaboratory validation of this method showed
significant and rapid losses of cyanides when lead sulfide was allowed to
remain in contact with the sample during holding times of three days or
less. As a result, the immediate filtration of samples preserved with lead
carbonate is essential (Reference 15.6)).
8.2.1.3 If the sample contains particulate matter that would be removed upon
filtration, the sample must be filtered prior to treatment with lead
carbonate to assure that cyanides associated with the particulate matter
are included in the measurement. The collected particulate matter must
be saved and the filtrate treated using the sulfide removal procedure
above (Section 8.2.1.1). The collected particulate and treated filtrate
must be recombined and homogenized, and then sent to the laboratory
for analysis.
8.2.2 Samples containing water soluble aldehydes—Treat samples containing or
suspected to contain formaldehyde, acetaldehyde, or other water soluble aldehydes
with 20 mL of 3.5% ethylenediamine solution (Section 7.10.2) per liter of sample.
8.2.3 Samples known or suspected to contain chlorine, hypochlorite, and/or
sulfite—Treat with 0.6 g of ascorbic acid (Section 7.10.3) per liter of sample.
EPA Method 330.4 or 330.5 may be used for the measurement of residual chlorine
(Reference 15.1).
10 January 2004
-------
Method OIA-1677, DW
8.3 Sample holding time—Maximum holding time for samples preserved as above is 14
days. Unpreserved samples must be analyzed within 24 hours, or sooner if a change in
cyanide concentration will occur. (See the footnotes to Table n at 40 CFR 136.3(e).)
S.OQuality Control
9.1 Each laboratory that uses this method is required to operate a formal quality assurance
program (Reference 15.9). The minimum requirements of this program consist of an
initial demonstration of laboratory capability, and the periodic analysis of LCSs and
MS/MSDs as a continuing check on performance. Laboratory performance is compared
to established performance criteria to determine if the results of the analyses meet the
performance characteristics of the method.
9.1.1 The laboratory shall make an initial demonstration of the ability to generate
acceptable precision and accuracy with this method. This ability is established as
described in Section 9.2.
9.2 Initial demonstration of laboratory capability
9.2.1 Method Detection Limit (MDL)—To establish the ability to detect cyanide at low
levels, the laboratory shall determine the MDL per the procedure in 40 CFR Part
136, Appendix B (Reference 15.4) using the apparatus, reagents, and standards
that will be used in the practice of this method. An MDL less than or equal to the
MDL listed in Section 1.4 must be achieved prior to practice of this method.
9.2.2 Initial Precision and Recovery (IPR)—To establish the ability to generate
acceptable precision and accuracy, the laboratory shall perform the following
operations:
9.2.2.1 Analyze four samples of the LCS (Section 7.12.2) according to the
procedure beginning in Section 10.
9.2.2.2 Using the results of the set of four analyses, compute the average percent
recovery (x) and the standard deviation of the percent recovery (s) for
cyanide. Use Equation 2 for calculation of the standard deviation of the
percent recovery.
January 2004 11
-------
Method OIA-1677, DW
EQUATION 2
s =
\
n - 1
where:
n = Number of samples
x = Percent recovery in each sample
9.2.3 Compare s and x with the acceptance criteria specified in Table 1. If s exceeds the
precision limit or x falls outside the range for recovery, system performance is
unacceptable and the problem must be found and corrected before analyses can
begin.
9.3 Matrix spike/matrix spike duplicate (MS/MSD)—The laboratory shall spike, in duplicate,
a minimum of 10 percent of all samples (one sample in duplicate in each batch of ten
samples) from a given discharge.
9.3.1 The concentration of the spike in the sample shall be determined as follows:
9.3.1.1 If, as in compliance monitoring, the concentration of cyanide in the
sample is being checked against a regulatory concentration limit, the
spiking level shall be at that limit or at 1 to 5 times higher than the
background concentration of the sample (determined in Section 9.3.2),
whichever concentration is higher.
9.3.1.2 If the concentration of cyanide in a sample is not being checked against a
limit, the spike shall be at the concentration of the LCS or at 1 to 5 times
higher than the background concentration, whichever concentration is
higher.
9.3.2 Analyze one sample aliquot out of each set of ten samples from each discharge
according to the procedure beginning in Section 11 to determine the background
concentration (B) of cyanide.
9.3.2.1 Spike this sample with the amount of mercury (n) cyanide stock solution
(Section 7.12.1) necessary to produce a cyanide concentration in the
sample of 2 mg/L. If necessary, prepare another stock solution
appropriate to produce a level in the sample at the regulatory compliance
limit or at 1 to 5 times the background concentration (per Section 9.3.1).
9.3.2.2 Spike two additional sample aliquots with the spiking solution and
analyze these aliquots to determine the concentration after spiking (A).
12 January 2004
^h;SK^
-------
Method OIA-1677, DW
9.3.3 Calculate the percent recovery of cyanide in each aliquot using Equation 3.
EQUATION 3
100 (A - B)
P =
where:
P = Percent recovery
A = Measured concentration of cyanide after spiking
B = Measured background concentration of cyanide
T = True concentration of the spike
9.3.4 Compare the recovery to the QC acceptance criteria in Table 1. If recovery is
outside of the acceptance criteria, and the recovery of the LCS in the ongoing
precision and recovery test (Section 9.6) for the analytical batch is within the
acceptance criteria, an interference is present. In this case, the result may not be
reported for regulatory compliance purposes.
9.3.5 If the results of both the MS/MSD and the LCS test fail the acceptance criteria,
the analytical system is judged to be out of control. In this case, the problem shall
be identified and corrected, and the analytical batch reanalyzed.
9.3.6 Calculate the relative percent difference (RPD) between the two spiked sample
results (Section 9.3, not between the two percent recoveries) using Equation 4.
EQUATION 4
ID. - D,|
D2)/2
x 100
where:
RPD = Relative percent difference
Dj = Concentration of cyanide in the spiked sample
D2 = Concentration of cyanide in the spiked duplicate sample
9.3.7 Compare the precision to the RPD criteria in Table 1. If the RPD is greater than
the acceptance criteria, the analytical system is judged to be out of control, and the
problem must be immediately identified and corrected, and the analytical batch
reanalyzed.
9.3.8 As part of the QC program for the laboratory, method precision and accuracy for
samples should be assessed and records should be maintained. After the analysis
of five spiked samples in which the recovery passes the test in Section 9.3.4,
compute the average percent recovery (Pa) and the standard deviation of the
January 2004 13
-------
Method OIA-1677, DW
percent recovery (sp). Express the accuracy assessment as a percent recovery
interval from Pa - 2sp to Pa + 2sp. For example, if Pa = 90% and sp = 10% for five
analyses, the accuracy interval is expressed as 70 - 110%. Update the accuracy
assessment on a regular basis (e.g., after each five to ten new accuracy
measurements).
9.4 Laboratory blanks—Laboratory reagent water blanks are analyzed to demonstrate
freedom from contamination.
9.4.1 Analyze a reagent water blank initially (i.e., with the tests in Section 9.2) and with
each analytical batch. The blank must be subjected to the same procedural steps
as a sample.
9.4.2 If cyanide is detected in the blank at a concentration greater than the ML, analysis
of samples is halted until the source of contamination is eliminated and a blank
shows no evidence of contamination.
9.5 Calibration verification—Verify calibration of the analytical equipment before and after
each analytical batch of 14 or fewer measurements. (The 14 measurements will normally
be 10 samples, 1 reagent blank, 1 LCS, 1 MS, and 1 MSD). Verification is accomplished
by analyzing the mid-range calibration standard and verifying that it is within the QC
acceptance criteria for recovery in Table 1. (The concentration of the calibration
verification depends on the calibration range being used.) Failure to verify calibration
within the acceptance criteria requires recalibration of the analysis system.
9.6 Laboratory control sample (LCS)—To demonstrate that the analytical system is in
control, and acceptable precision and accuracy is being maintained with each analytical
batch, the laboratory shall perform the following operations.
9.6.1 Analyze a LCS (Section 7.12.2) with each analytical batch according to the
procedure in Section 10.
9.6.2 If the results for the LCS are within the acceptance criteria specified in Table 1,
analysis of the batch may continue. If, however, the concentration is not within
this range, the analytical process is not in control. In this event, correct the
problem, repeat the LCS test, and reanalyze the batch.
9.6.3 The laboratory should add results that pass the specification in Section 9.6.2 to
IPR and previous LCS data and update QC charts to form a graphic representation
of continued laboratory performance. The laboratory should also develop a
statement of laboratory data quality for cyanide by calculating the average percent
recovery (R) and the standard deviation of the 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%.
9.7 Reference Sample—To demonstrate that the analytical system is in control, the laboratory
should periodically test an external reference sample, such as a Standard Reference
14 January 2004
-------
Method OIA-1677, DW
Material (SRM) if an SRM is available from the National Institutes of Standards and
Technology (NIST). The reference sample should be analyzed quarterly, at a minimum.
Corrective action should be taken if the measured concentration significantly differs from
the stated concentration.
10.0 Calibration and Standardization
This section describes the procedure to calibrate and standardize the FIA system prior to cyanide
determination.
10.1 Instrument setup
10.1.1 Set up the FIA system and establish initial operating conditions necessary for
determination of cyanide. If the FIA system is computerized, establish a method
for multi-point calibration and for determining the cyanide concentration in each
sample.
10.1.2 Verify that the reagents are flowing smoothly through the FIA system and that the
flow cell is purged of air bubbles.
10.2 Instrument Stabilization
10.2.1 Load a 10 mg/L KCN standard (Section 7.8.3) into the sampling valve and inject
into the FIA system.
10.2.2 Continue to inject 10 mg/L KCN standards until 3 successive peak height or area
results are within 2% RSD, indicating that the electrode system is stabilized.
10.2.3 Following stabilization, inject the highest concentration calibration standard until
3 successive peak height or area results are within 2% RSD indicating
stabilization at the top of the calibration range.
10.3 External standard calibration
10.3.1 Inject each of a minimum of 3 calibration standards. One of the standards should
be at the minimum level (ML) unless measurements are to be made at higher
levels. The other concentrations should correspond to the expected range of
concentrations found in samples or should define the working range of the FIA
system.
10.3.2 Using injections of a constant volume, analyze each calibration standard
according to Section 11 and record peak height or area responses against the
concentration. The results can be used to prepare a calibration curve.
Alternatively, if the ratio of response to amount injected (calibration factor) is
constant over the working range (<10% RSD), linearity through the origin can be
assumed and the averaged calibration factor (area/concentration) can be used in
place of a calibration curve.
January 2004 15
-------
Method OIA-1677, DW
11.0 Procedure
This section describes the procedure for determination of available cyanide using the FIA system.
11.1 Analysis of standards, samples, and blanks
11.1.1 Ligand-exchange reagent treatment of standards, samples, and blanks.
11.1.2 To 100-mL of cyanide-containing sample (or standard or blank) at pH of
approximately 12, add 100 uL of ligand-exchange reagent Part B (Section 7.11.5),
50uL of ligand-exchange reagent Part A (Section 7.11.4), and mix thoroughly.
Load the sample, standard, or blank into the sample loop.
NOTE: The ligand-exchange reagents, when added to 100 mL of sample at
the specified volume, will liberate cyanide from metal complexes of
intermediate stability up to 5 mg/L cyanide ion. If higher
concentrations are anticipated, add additional ligand-exchange reagent,
as appropriate, or dilute the sample.- The ligand-exchange reagents
have an approximate lifetime of 6 months after opening. The reagents
should be stored in a refrigerator at 4°C. Samples should be analyzed
within 2 hours of adding the ligand-exchange reagents. The reagents
should always be used in solutions similar to cyanide samples (pH 12
adjusted). It is recommended that the ligands be checked monthly.
This can be done by preparing pH 12 adjusted 2 mg/1 solutions of
mercury(II) cyanide (Section 7.4) and of potassium nickel(II) cyanide
(Section 7.5). Add ligand-exchange reagent B to the mercury(II)
standard and ligand-exchange reagent A to the potassium nickel(II)
cyanide standard and confirm cyanide recovery.
11.1.3 Inject the sample and begin data collection. When data collection is complete,
analyze the next sample, standard or blank in the batch until analyses of all
samples in the batch are completed.
12.0 Data Analysis and Calculations
12.1 Calculate the concentration of material in the sample, standard or blank from the peak
height or area using the calibration curve or calibration factor determined in Section 10.3.
12.2 Reporting
12.2.1 Samples—Report results to three significant figures for cyanide concentrations
found above the ML (Section 1.4) in all samples. Report results below the ML as
<2 /ig/L, or as required by the permitting authority or permit.
12.2.2 Blanks—Report results to three significant figures for cyanide concentrations
found above the MDL (Section 1.4). Do not report results below the MDL unless
required by the permitting authority or in the permit.
16 January 2004
-------
Method OIA-1677, DW
13.0 Method Performance
13.1 Method detection limit (MDL)—MDLs from nine laboratories were pooled to develop
the MDL of 0.5 ju,g/L given in Section 1.4 (Reference 15.12).
13.2 Data obtained from single laboratory testing of the method are summarized in Table 2
and show recoveries and reproducibility for "free" forms of cyanide, including the
recovery and reproducibility of silver, nickel, and mercury cyanide species.
Determination of these species tends to be problematic with other methods for the
determination of available cyanide. As it is the case with other methods used for
available cyanide, iron cyanide species were not recovered and recoveries for gold and
cobalt species were zero or very low. The complete results from the single laboratory
study are available in the Report of the Draft OIA Method 1677 Single Laboratory
Validation Study (Reference 15.11).
13.3 Listed in Table 1 are the QC acceptance criteria developed from an interlaboratory
validation study of this method. This study was conducted following procedures
specified in the Guide to Method Flexibility and Approval of EPA Water Methods
(Reference 15.10). In this study, a total of nine laboratories performed analyses for
various water matrices. Table 3 shows a summary of the interlaboratory results which
include the accuracy and precision data as % recoveries and relative standard deviations.
In addition to spikes of easily dissociable cyanides, some samples contained known
amounts of cyanides that are not recoverable (e.g., Pt and Fe complexes) and thiocyanate
was spiked to one sample to investigate the potential for interference. The complete
study results are available in the Report of the Draft OIA Method 1677 Interlaboratory
Validation Study (Reference 15.12).
14.0 Pollution Prevention and Waste Management
14.1 The laboratory is responsible for complying with all Federal, State, and local regulations
governing waste management, particularly hazardous waste identification rules and land
disposal restrictions, and for protecting the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations. Compliance with all
sewage discharge permits and regulations is also required. An overview of requirements
can be found in Environmental Management Guide for Small Laboratories (EPA 233-B-
98-001).
14.2 Samples containing cyanide, certain metals, and acids at a pH of less than 2 are hazardous
and must be treated before being poured down a drain or must be handled as hazardous
waste.
14.3 For further information on waste management, consult Less is Better: Laboratory
Chemical Management for Waste Reduction, Reference 15.8.
January 2004 17
-------
Method OIA-1677, DW
15.0 References
15.1 Environmental Monitoring Systems Laboratory. EPA Method 335.1. In: Methods for the
Chemical Analysis of Water and Wastes (EPA/600/4-79-020). Environmental Protection
Agency, Cincinnati, Ohio. Revised March 1983.
15.2 American Public Health Association, American Waterworks Association, Water
Pollution Control Board. Methods Section 4500-CN in Standard Methods for the
Examination of Water and Wastewater, 19th Edition. American Public Health
Association, Washington, DC. 1995.
15.3 Ingersol, D.; Harris, W.R.; Bomberger, D.C.; Coulson, D.M. Development and
Evaluation Procedures for the Analysis of Simple Cyanides, Total Cyanides, and
Thiocyanate in Water and Waste Water (EPA-600/4-83-054), 1983.
15.4 Code of Federal Regulations, Title 40, Part 136, Appendix B. U.S. Government Printing
Office, Washington, D.C., 1994.
15.5 ALPKEM CNSolution Model 3000 Manual. Available from ALPKEM / OI Analytical,
Box 9010, College Station, TX 77842-9010.
15.6 Milosavljevic, E.B.; Solujic, L.; Hendrix, J.L. Environmental Science and Technology,
Vol. 29, No. 2,1995, pp 426-430. Rapid Distillationless "Free Cyanide" Determination
by a Flow Injection Ligand Exchange Method.
15.7 Wilmont, J.C.; Solujic, L.; Milosavljevic, E. B.; Hendrix, J.L.; Reader, W.S. Analyst,
June 1996, Vol. 121, pp 799-801. Formation of Thiocyanate During Removal of Sulfide
as Lead Sulfide Prior to Cyanide Determination.
15.8 Less is Better: Laboratory Chemical Management for Waste Reduction. Available from
the American Chemical Society, Department of Government Regulations and Science
Policy, 1155 16th Street, NW, Washington, DC 20036.
15.9 Handbook for Analytical Quality Control in Water and Wastewater Laboratories (EPA-
600/4-79-019), USEPA, NERL, Cincinnati, Ohio 45268 (March 1979).
15.10 Guide to Method Flexibility and Approval of EPA Water Methods, December, 1996,
(EPA-821-D-96-004). Available from the National Technical Information Service
(PB97-117766).
15.11 Report of the Draft OIA Method 1677 Single Laboratory Validation Study, November
1996. Available from ALPKEM / OI Analytical, Box 9010, College Station, TX 77842-
9010.
15.12 Report of the Draft OIA Method 1677 Interlaboratory Validation Study, March 1997.
Available from ALPKEM / OI Analytical, Box 9010, College Station, TX 77842-9010.
18 January 2004
-------
Method OIA-1677, DW
16.0 Tables
Table 1. Quality Control Acceptance Criteria
Criterion
Initial Precision and Recovery
Ongoing Precision and Recovery
(Laboratory Control Sample)
Calibration Verification
Matrix Spike/Matrix Spike
Duplicate
Required Recovery Range
(%)
92 - 122
82 - 132
86-118
82 - 130
Precision
<5.1%RSD
N/A
N/A
<11%RPD
Table 2. Species-Dependent Cyanide Recoveries Using Draft Method 1677(1)
Species
[Zn(CN)4]2-
[Cd(CN)4f
[Cu(CN)J2-
[Ag(CN)4f
[Ni(CN)4f
[Hg(CN)4]2-
Hg(CN)2
[Fe(CN)4]4-
[Fe(CN)6]3-
[Au(CN)2]-
[Co(CN)6f
0.20ng/mLCN-
97.4 (0.7)
100.0 (0.8)
100.9 (1.3)
101.8 (0.9)
104.3 (0.2)
100.0 (0.6)
103.4 (0.4)
0.0
0.0
1.3(2) (0.0)
2.9(2) (0.0)
2.00 ng/mL CN-
98.5 (0.7)
100.0 (0.2)
99.0 (0.6)
100.0 (0.5)
103.0 (0.5)
99.0 (0.3)
98.0 (0.3)
0.0
0.0
0.0
2.0(2) (0.0)
1 Values are % recoveries; numbers in parentheses are percent relative standard deviations.
2 Commercial product contains some free cyanide.
January 2004
19
-------
Method OIA-1677, DW
Table 3. Cyanide Recoveries From Various Aqueous Matrices
Sample
Reagent water w/O.OlM
NaOH
POTW secondary effluent
Petroleum Refinery
Secondary Effluent
Coke Plant Secondary
Effluent
Rolling Mill Direct Filter
Effluent
Metals Finishing Indirect
Primary Effluent
Reagent water w/O.OlM
NaOH
Reagent water w/O.OlM
NaOH
Mining Tailing Pond Effluent
Sample CN
Concentration
0\ig/L
3.0 \igfL
9.9 jig/L
14.0 ng/L
4-Oyg/L
l.Oug/L
Ou.g/L
0|ig/L
842u.g/L
Added CN(I)
Concentration
lOOug/LasKCN
lOOng/LasKCN;
2mg/Las[Pt(CN)6]4-
2 mg/L as KCN;
5 mg/L as [FeCCNy4"
50 ng/L as KCN
none
200 [igfL as KCN;
2 mg/L as KSCN
200 jig/L as KCN
10 mg/L as KCN;
10 mg/L as [Pt(CN)6]"-
4 mg/L as KCN
Average %
Recovery
108
102
87
95
80
92
101
103
98
%RSD
4.0
7.0
21
4.0
41
16
8.0
2.0
3.0
1 Cyano-complexes of Pt and Fe were added to the POTW and petroleum
refinery effluents, respectively; and thiocyanate was added to the metals
finishing effluent to demonstrate that the FI/LE system does not determine
these forms of cyanide.
17.0 Glossary of Definitions and Purposes
The definitions and purposes are specific to this method but have been conformed to common
usage as much as possible.
17.1 Units of weights and measures and their abbreviations
17.1.1 Symbols
°C degrees Celsius
% percent
± plus or minus
> greater than or equal to
17.1.2 Alphabetical characters
g gram
L liter
mg milligram
mg/L milligram per liter
ptg microgram
ptg/L microgram per liter
20
January 2004
-------
Method OIA-1677, DW
mL milliliter
ppm parts per million
ppb parts per billion
M molar solution
17.2 Definitions
17.2.1 Available cyanide consists of cyanide ion (CN~), hydrogen cyanide in water
(HCNaq) and the cyano-complexes of zinc, copper, cadmium, mercury, nickel, and
silver.
17.2.2 Calibration blank—A 100 mL volume of reagent water treated with the ligand-
exchange reagents and analyzed using the FIA procedure.
17.2.3 Calibration standard (CAL)—A solution prepared from the dilution of stock
standard solutions. A 100 mL aliquot of each of the CALs are subjected to the
analysis procedure. The resulting observations are used to calibrate the
instrument response with respect to the analyte concentration.
17.2.4 Discharge—Specific discharge (also known as "matrix type") means a sample
medium with common characteristics across a given industrial category or
industrial subcategory. Examples include: C-stage effluents from chlorine bleach
mills in the Pulp, Paper, and Paperboard industrial category; effluent from the
continuous casting subcategory of the Iron and Steel industrial category; publicly
owned treatment work (POTW) sludge; and in-process streams in the Atlantic and
Gulf Coast Hand-shucked Oyster Processing subcategory.
Specific discharge also means a discharge with characteristics different from other
discharges. Therefore, if there are multiple discharges from a facility all with the
same characteristics, these are the same discharge for the purpose of
demonstrating equivalency of a method modification. In this context,
"characteristics" means that results of the matrix spike and matrix spike duplicate
(MS/MSD) tests with the unmodified method meet the QC acceptance criteria for
recovery and relative percent difference (RPD).
17.2.5 Initial precision and recovery (DPR)—Four aliquots of the LRB spiked with the
analytes of interest and used to establish the ability to generate acceptable
precision and accuracy. An IPR is performed the first time this method is used
and any time the method or instrumentation is modified.
17.2.6 Laboratory control sample (LCS)—An aliquot of LRB to which a quantity of
mercury (II) cyanide stock solution is added in the laboratory. The LCS is
analyzed like a sample. Its purpose is to determine whether the methodology is in
control and whether the laboratory is capable of making accurate and precise
measurements.
January 2004 21
-------
Method OIA-1677, DW
17.2.7 Laboratory reagent blank (LRB)—An aliquot of reagent water that is treated like a
sample including exposure to all glassware, equipment, and reagents that are used
with other samples. The LRB is used to determine if the method analyte or other
interferences are present in the laboratory environment, reagents, or apparatus.
17.2.8 Matrix spike/matrix spike duplicate (MS/MSD)—An aliquot of an environmental
sample to which a quantity of the method analyte is added in the laboratory.
MS/MSDs are analyzed like a sample. Their purpose is to determine whether the
sample matrix contributes bias to the analytical results. The background
concentration of the analyte in the sample matrix must be determined in a separate
aliquot and the measured values in the MS/MSD corrected for the background
concentration.
17.2.9 Minimum level (ML)—The level at which the entire analytical system shall give a
recognizable signal and acceptable calibration point, taking into account method
specific sample and injection volumes.
17.2.10 Ongoing precision and recovery (OPR)—See Laboratory control sample
22 January 2004
------- |