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Significance and Use
5.1 Organophosphate pesticides affect the nervous system by disrupting the enzyme that regulates acetylcholine, a neurotransmitter. They were developed during the early 19th century, but their effects on insects, which are similar to their effects on humans, were discovered in 1932. Some are poisonous and were used as chemical weapon agents. Organophosphate pesticides are usually not persistent in the environment.4, 5
5.2 This test method is for the analysis of selected organophosphorous-based chemical weapon agent degradation products from Sarin (GB), Soman (GD), Tabun (GA) and VX. This method has been investigated for use with reagent and surface water.
1.1 This procedure covers the determination of diisopropyl methylphosphonate (DIMP), ethyl hydrogen dimethylamidophosphate (EHDMAP), ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), methylphosphonic acid (MPA) and pinacolyl methylphosphonic acid (PMPA) (referred to collectively as organophosphonates in this test method) in surface water by direct injection using liquid chromatography (LC) and detected with tandem mass spectrometry (MS/MS) using electrospray ionization (ESI). These analytes are qualitatively and quantitatively determined by this method. This method adheres to single reaction monitoring (SRM) mass spectrometry.
1.4 The detection verification level (DVL) and reporting range for the organophosphonates are listed in Table 1.
1.4.1 The DVL is required to be at a concentration at least three times below the reporting limit (RL) and have a signal/noise ratio greater than 3:1. Fig. displays the signal/noise ratios at the DVLs for the organophosphonates in the ESI positive mode and Fig. 2 in the ESI negative mode.
1.4.2 The reporting limit is the concentration of the Level 1 calibration standard as shown in Table 2 for the organophosphonates except for MPA in the ESI negative mode which is at Level 2 due to not meeting the DVL criteria at the lower concentration level. The DVL for MPA in the ESI negative mode is at 20 μg/L, which forces a raised reporting limit. However, the multi-laboratory validation required a spike of all target analytes at Level 1 concentrations. The mean recovery for MPA in the ESI negative mode at this level was 98.7 % as shown in Table 3. If your instrument’s sensitivity can meet the requirements in this test method, MPA may have a 50 μg/L reporting limit.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
D3694 Practices for Preparation of Sample Containers and for Preservation of Organic Constituents
D3856 Guide for Management Systems in Laboratories Engaged in Analysis of Water
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
E2554 Practice for Estimating and Monitoring the Uncertainty of Test Results of a Test Method Using Control Chart Techniques
Other DocumentsEPApublicationSW-846 Test Methods for Evaluating Solid Waste, Physical/Chemical Methods Available from United States Environmental Protection Agency (EPA), Ariel Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http://www.epa.gov.
ICS Number Code 13.060.50 (Examination of water for chemical substances)
UNSPSC Code 41115705(Liquid chromatographs); 12352103(Organo metallic compounds)