Single-sided membrane introduction mass spectrometry for on-line determination of semi-volatile organic compounds in air

Construction, optimization, and testing of a novel single-sided configurati on for a semi-permeable [poly( dimethylsiloxane); PDMS] membrane introducti on system for mass spectrometry is described. On-line detection of semi-vol atile organic compounds of environmental interest is shown, including linda ne (a pesticide), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) (an explosi ve), butylated hydroxytoluene (BHT) (an antioxidant), 1,2-dichlorobenzene, dimethylmethyl phosphonate (DMMP) (a chemical warfare agent simulant) and n aphthalene. The technique has limits of detection in the sub-ppb range, wit h rise times of 4 to 7 s and fall times of 12 to 36 s and a response that i s linear over 4 orders of magnitude (from 0.1 ppb to 1000 ppb for DMMP). Th e cycle time, from crude air sampling to acquisition of results, is approxi mately 1 min. No sample preparation is necessary.