Guidelines on Validation of Non-Regulatory Chemical and Radiochemical Methods (EPA/600/B-22/001, 2022): Method Validation Summary for SW-846 Methods 3512 and 8327


Guidelines on Validation of Non-Regulatory Chemical and Radiochemcial Methods
(EPA/600/B-22/001,2022): Method Validation Summary for SW-846 Methods 3512 and 8327

The Guidelines provide collected information on critical areas of method performance assessment for
validation studies. The Method Validation Summary Table from the Gudelines is designed to provide
consistency in delivery of summary method validation results in a concise, easy-to-prepare and share
format. Below is an example of the Table completed for the US EPA SW-846 Methods 3512 and 8327
Links to the complete report can be found at the end of the Table.

A

Validation Design

Description

1

Number of Laboratories

8

2

Number of Matrices

3

3

Types of Matrices Tested (water,
soil, sediment, etc.)

Groundwater, surface water, wastewater

B

Method Validation Overview

Description

1

Method Title

• SW-846 Method 3512: Solvent Dilution of
Non-Potable Waters
• SW-846 Method 8327: Per- and Polyfluoroalkyl
Substances (PFAS) by Liquid Chromatography-
Tandem Mass Spectrometry (LC/MS/MS)

2

Organization

EPA/Office of Land and Emergency
Management/Office of Resource Conservation and
Recovery

3

Date

July 2021

4

Purpose

To validate the preparation and analysis of non-potable
water samples for select PFAS by LC/MS/MS

5

Qualitative or Quantitative

Quantitative

6

Target Analytes/Parameters

Validated for 24 PFAS target analytes, including:
• C4-C14 perfluorinated carboxylic acids

•	C4-C10 perfluorinated sulfonic acids,

• 4:2, 6:2, and 8:2 Fluorotelomer Sulfonic Acids
(FTS)

• perfluorooctane sulfonamide

•	N-ethyl and N-methyl perfluorooctane

sulfonamidoacetic acids
Please refer to Method 8327 for more detail

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c

Method Development
Considerations

Description and/or Results

1

Sample Cost

Not Determined

2

Recommended Sample Holding
Times

Sample collection to preparation: 14 days
Sample preparation to analysis: 30 days

3

Sample Preservation

Refrigerate at 0-6°C

4

Waste Generation

These methods generate relatively small amounts of
waste due to:

• Small recommended sample volumes;
• Low volumes of reagents and solvents used for
sample preparation; Liquid chromatography
columns with particle sizes < 2 (.un achieve
efficient separations at low flow rates

vfotes on Section C:



-C2 Holding times are published as guidelines and were based on holding time studies conducted for
other PFAS methods, including EPA methods 533 and 537.1 and ASTM D7979-20.

D

Method Performance
Characteristic

Description and/or Results

1

Bias/Trueness

Average (median) recovery across eight laboratories
ranged from 80-118% at 95% confidence for every
target analyte except 6:2 FTS in each matrix type and
prepared concentration level.

2

Detection Capability and
Quantification Capability

Lower limits of quantitation (LLOQs) across eight
laboratories were verified at nominal concentrations of
10-20 ng/L at 95% confidence for all target analytes
except for 8:2 FTS (40 ng/L) and 6:2 FTS (160 ng/L).

3

Instrument Calibration

Target analytes were calibrated by external standard
using weighted regression.

4

Measurement Uncertainty

Not Applicable

5

Precision

Relative standard deviation (RSD) of measured
concentrations in spiked samples was <50% in every
matrix and spike level combination in each laboratory
except for PFOS in one laboratory/matrix/spike level
and 6:2 FTS in three laboratory/matrix/spike level
combinations.

6

Range

LC/MS/MS initial calibration range was from 5 to 200
ng/L (nominal). No attempt was made to determine an
upper limit for quantitative analysis.

7

Ruggedness

Formal ruggedness testing was not performed as part of
the validation study.

8

Selectivity in the Presence of
Interferences

No major sources of interferences were observed that
impacted qualitative identification of target analytes.

vfotes on Section D:

- D1 Validation study samples were tested unspiked or spiked at nominal concentrations of 60 and 200
ng/L. Each laboratory tested 5 replicate spiked samples of each matrix at each prepared concentration.
Samples were prepared centrally and shipped to laboratories, which were blind to the identities of the

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samples and their prepared concentrations. Half of the participating laboratories reported background
contamination with 6:2 FTS.

- D2 High verified LLOQs for 6:2 FTS were attributed to background contamination in half of
participating laboratories. Methods 3512 and 8327 are performance-based, and laboratories are required
to establish and periodically verify LLOQs at which they can routinely meet the acceptance criteria for all
categories of quality controls. Refer to Method 8000D Section 9.7 and Method 8327 Section 9.9 for more
information about establishing and verifying LLOQs https://www.epa.gov/faw~sw846/sw~846-
compendium.

- D4 Methods 3512 and 8327 are performance-based, and, like many other SW-846 methods, they
recommend applying statistically-based or project-defined acceptance limits for recovery and precision in
field samples and associated prepared quality control samples.

- D5 PFOS imprecision was attributed to variability in background concentrations in wastewater samples,
and 6:2 FTS imprecision was attributed to laboratory contamination in half of participating laboratories.

- D7 Laboratory deviations from the method validation study protocol led to the addition cautionary
measures to the methods related to ruggedness, including: 1) avoiding aqueous subsampling prior to
adding sufficient organic solvent; and 2) avoiding storage of prepared samples and standards in glass
containers.

- D8 Some PFAS target analytes do not make secondary product ions with sufficient relative abundance
to be useful for supporting qualitative identification.