1.1 This is a gas chromatographic (GC) test method applicable to the determination of certain nitrogen- and phosphorus-containing pesticides in ground water and finished drinking water. The analytes listed in Table 1 have been validated using this test method.

1.2 This test method has been validated on reagent water and finished drinking water by 10 volunteer laboratories. Summary statistics were calculated for mean recovery, overall method precision and bias and single analyst precision using a computer program, Interlaboratory Method Validation Study (IMVS).2

1.3 Collaborative study showed the test method to be acceptable for all analytes tested except merphos, which decomposed in the GC injection port.

1.4 This test method is restricted to use by or under the supervision of analysts experienced in the use of GC and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this test method using the procedure described in 12.3.

1.5 Analytes that are not separated chromatographically, that is, analytes which have very similar retention times, cannot be individually identified and measured in the same calibration mixture or water sample unless an alternative technique for identification and quantitation exist (13.5).

1.6 When this test method is used to analyze unfamiliar samples for any or all of the analytes above, analyte identifications should be confirmed by at least one additional qualitative technique.

1.7 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1 and 2.