Pentafluorophenylhydrazine as a coating reagent for the HRGC-MS determination of semi volatile carbonyl compounds in air

Sensitive detection of semi-volatile carbonyl compounds in air can be achie ved by using pentafluorophenylhydrazine-coated (PFPH) silica cartridges. Hy drazones formed during sampling are extracted with dichloromethane-acetonit rile and analysed by GC-MS operated in selected-ion-monitoring mode (SIM). The low detection limits reached (similar to 20 ppt (v/v) for sampling peri ods of 1 h) makes this method a valid alternative to other HPLC-UV and HRGC -MS techniques recently developed. Several experimental variables, for exam ple collection and derivatization efficiency, interference by ozone, and st orage stability of blank and sampled cartridges, have been investigated. Co mparison field tests with the classical dinitrophenylhydrazine (DNPH) metho d showed results to be very consistent for C-4-C-11 n-alkanals and 6-h samp ling periods during which six PFPH cartridges were run in parallel (each fo r 1 h) with one 2,4-dinitrophenylhydrazine (DNPH)-coated cartridge.