A method based on high-performance liquid chromatography is described for the simultaneous determination of 4,4′-methylenebis(2-chloroaniline)(MOCA) and 2-chloroaniline (OCA) in factory atmospheres. Tenax-GC is employed as the adsorbent in the sampling device to collect amine vapours, and a filter is used to collect particulate amines. Comparison is made between ultraviolet and electrochemical detection; with electrochemical detection much greater specificity is obtained and the method can be used to measure MOCA and OCA down to 20 and 10 pg injected, respectively; these levels are significantly lower than those attainable with ultraviolet detection.