Objective To establish a method to determine picric acid in workplace air by headspace gas chromatography.
Methods Air samples containing picric acid were collected by millipore filter, eluted by pure water, and derivatized with sodium hypochlorite before determined by headspace gas chromatography-electron capture detector (GC-EDC).
Results A good linearity (r=0.999 7) was obtained when the concentrations of picric acid were in the range from 0.01 μg/mL to 1.00 μg/mL. The detection limit was 0.000 06 μg/mL (100 μL injection volume), the minimum detectable concentration was 0.000 008 mg/m3 (calculation with 75 L sampling volume, 10 mL desorption volume), the relative standard deviation was 1.42%-1.61%, the average recovery rate was 97.9%-99.7%, the average elution efficiency was 95.9%-97.3%, and the sampling efficiency was 95.1%-97.1%. The millipore filters absorbed 10 μg picric acid, and were stable under room temperature for at least 15 days.
Conclusion This determination method meets the requirements of Guide for Establishing Occupational Health Standards Part 4:Determination Methods of Air Chemicals in Workplace (GBZ/T 210.4-2008) and is suitable for the determination of picric acid in workplace air.
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