Determination of maleic anhydride in occupational atmospheres

Maleic anhydride has many uses in industry, but workers' exposure to it is poorly known. Our new method allows airborne maleic anhydride to be determined with a limit of quantification of 1 microg/m3 per 12 1 of air, i.e., the concentration of about 0.01 times the occupational exposure standard (0.4 mg/m3). Air samples are collected in Tenax tubes containing sodium sulfate as a drying agent. Maleic anhydride is eluted with methyl tert.-butyl ether containing 5% acetonitrile and 0.1% acetic anhydride, and determined by capillary gas chromatography with electron-capture detection without interference from generic anhydrides. The tested method suits both long-term and short-term measurements.