An HPLC method for monitoring exposure of workers to 3-chloro-4-fluoroaniline (CFA) is described. It is based on the detection of a major urinary metabolite, 2-amino-4-chloro-5-fluorophenyl sulphate, and is superior to the previously adopted GC method. The limit of detection for the metabolite, 2-amino-4-chloro-5-fluorophenyl sulphate, is less than or equal to 0.01 mg/L (as CFA equivalent), with a coefficient of variation obtained over the range 1-15 mg/L of 4%. The HPLC method avoids the need for derivatization (cf. GC) and is consequently a much quicker and cheaper monitoring method. Urine samples from plant workers may be stored at 4 degrees C for a period of three months without loss of the metabolite.
