ORGANOPHOSPHORUS COMPOUNDS BY GAS CHROMA

Method 8141 provides gas chromatographic conditions for the determination of part per billion concentrations of organophosphorus compounds. Prior to the use of this method, appropriate sample preparation techniques must be used. Water samples are extracted at a neutral pH with methylene chloride by using a separatory funnel (Method 3510), a continuous liquid-liquid extractor (Method 3520), solid-phase extraction (Method 3535), or other appropriate technique. Solid samples are extracted using Soxhlet extraction (Method 3540) or automatedSoxhlet extraction (Method 3541), using methylene chloride/acetone (1:1), pressurized fluid extraction (Method 3545), or other appropriate technique. Both neat and diluted organic liquids (Method 3580, Waste Dilution) may be analyzed by direct injection. 2.2 Analysis is performed on a gas chromatograph with a flame photometric or nitrogenphosphorus detector. 2.3 Organophosphorus esters and thioesters can hydrolyze under both acid and base conditions. Therefore, sample preparation procedures employing acid and base partitioning procedures are not appropriate for extracts to be analyzed by Method 8141. 2.4 Ultrasonic Extraction (Method 3550) is not an appropriate sample preparation method for Method 8141 because of the potential for destruction of target analytes during the ultrasonic extraction process and should not be used.