Gas chromatographic/mass spectrometric analysis of extracts of workplace air samples for nitrosamines.
Am Ind Hyg Assoc J 1987 Mar; 48(3):265-270
Three procedures employing gas chromatography and mass spectrometry for confirming the presence of eight N-nitrosamines in air were described. A Hewlett-Packard Model 5840 gas chromatograph (GC) was interfaced to a VG Micro Mass 7070 HS mass spectrometer (MS) and a VG Model 2250 data system. GC was equipped with a fused silica capillary column. Full Scan EI mass spectra were obtained from analysis of eight standard nitrosamine samples. The MS was adjusted to a resolution of 4000 and operated in the selected ion recording (SIR) mode using voltage switching. GC/MS/high resolution multiple ion detection (HRMID) analyses were performed with the MS operating in the SIR mode. The molecular and other characteristic ions were arranged into six groups, each group containing two or less ions plus the perfluorokerosene reference ion at m/e 68.9952. The overall standard deviation of retention times over a concentration range of 0.02 to 2 nanograms/microliter was within 2 seconds. The detection limit was about 2 nanograms for the full scan GC/MS, 10 to 20 picograms (pg) for the screening method, and 2 to 4pg for the GC/MS/HRMID procedure. A final identification step involved reanalysis of the extract using full scan GC/MS. In an analysis, N- nitrosodimethylamine (62759) (NNDA) was identified by its retention time and by computer matching the mass spectrum with standard spectra in the library. The useful range for confirming NNDA in workplace air samples was estimated at 0.1 to 2.5 micrograms/cubic meter (microg/m3) for the screening and 0.02 to 2.5microg/m3 for the GC/MS/HRMID procedures. The author states that the detection limits of the procedures, ranging from 2 to 2000pg per injection, are sufficient for typical workplace samples.
NIOSH-Author; Analytical-chemistry; Gas-chromatography; Mass-spectrometry; Nitroso-compounds; Diamines; Air-samples; Workplace-studies; Trace-analysis; Analytical-methods
American Industrial Hygiene Association Journal