OBJECTIVETo establish a method for determining o-tolidine in workplace air by gas chromatography.

METHODSo-tolidine in workplace air was collected with a glass fiber filter, desorbed with methanol, and determined by gas chromatography-flame ionization detector.

RESULTSThe concentration of o-tolidine showed a linear relationship with peak area within 0.04∼9.00 µg/ml; the detection limit was 0.04 µg/ml; the minimum detectable concentration was 0.0002 mg/m(3) (calculated by 375 L air sample); the sampling efficiency was 93%∼100%; the elution efficiency was 94%∼96%; the relative standard deviation was 0.8-2.5%. Sample could be stored at 4 °C for at least 8 days and at room temperature for as long as 6 days.

CONCLUSIONThis determination method meets the requirements of Guide for establishing occupational heath standards-Part 4 Determination methods of air chemicals in workplace (GBZ/T 210.4-2008) and is suitable for determination of o-tolidine in workplace air.