Using A Single Purge And Trap Gas Chromatography Mass Spectrometer System To analyze For Voltatile Organics In air, Water And Soil In A Mobile Laboratory

摘要

A method was developed and validated using a transportable purge and trap gas chromatograph mass spectrometer (GC/MS) system for volatile organic compound (VOC) analysis. Routine purge and trap methodology allow for the use of one multi point calibration curve to quantify for the presence of volatile organics in water and high level soil samples. Atypical in application, is the use of a single purge and trap concentrator for the analysis of air. While not having to change the instrumet configuration, an aliquot of air can be directly introduced into the purge and trap, and the data generated accurately compared to the water matrices standard curves. Air analysis starts by withdrawing air with a 100 milliliter (ml) gas tight syringe and injecting the sample into the sample port of the purge and trap GC/MS system. A vacuum assisted vaporized methanolic VOC standard is prepared in the syringe, and the measured response of the analytes were compared to the standard water curves response feactors. For most of the 60 VOC's tested the recoveries of the methanolic based verification standard ranged from 80percent to 120percent and the realtive standard deviation values totaled less than 20percent. The method for air analysis was also validated by analyzing a certified gas standard from an independent source. The quantitation range of the air syringe technique extended from low ppbv to 100 ppbv levels and the data quality of the air analysis was the same as the water analysis. A field feasibility case study was conducted analyzng water, soil and air with a transporbable purge and trap GC/MS system on location at a highly contaminated LUST site in Connecticut.