SPECIATION OF ORGANOLEAD COMPOUNDS IN AIR BY GC-MS-SIM

A procedure for trapping tetraalkyl-lead (TAL) compounds in air is described. The system consists of a solid cartridge containing a mixture (65:35, w/w) in series of Porapak and Tenax. A contaminated atmosphere with a known concentration of TAL was generated in the laboratory. This atmosphere was trapped in the solid cartridge. After passing synthetic air through the system, the cartridge was extracted with hexane in an ultrasonic bath. The organic extract was concentrated under nitrogen current and the compounds were analyzed by GC-MS-SIM. Each step of the process was studied independently. Losses of volatile compounds in the evaporation step, the storage of the cartridge over 45 days before the extraction step and the breakthrough volumes have been established in order to achieve optimization of the whole process. The analytical conditions of the final quantification include a linear range between 1.32 pg and 50.10 ng for Et(4)Pb, and 5.30 pg and 51.40 ng for Me(4)Pb. The detection limits are 0.66 pg, 3.40 pg, 1.07 pg, 1.05 pg and 2.60 pg for Et(4)Pb, Et(3)MePb, Et(2)Me(2)Pb, EtMe(3)Pb and Me(4)Pb, respectively.