Determination of 4,4'-methylenedianiline in hydrolysed human urine by micro liquid chromatography with ultraviolet detection.

4,4'-Methylenedianiline was determined in human urine by micro liquid chromatography with ultraviolet detection. The combination of a thorough work-up and the high mass sensitivity of micro liquid chromatography gave the method very high sensitivity. Derivatization with pentafluoropropionic anhydride enhanced the resolution of the 4,4'-dimethylenedianiline peak. The detection limit, defined as blank plus three times the standard deviation of the blank, was 2 nmol/l of urine, for 10-microliters injection volumes. The detection limit, defined as three times the noise, was about ten times better. The within- and between-assay coefficients of variation were 4 and 6%, respectively, for samples containing 40 nmol/l. The method was applied for the monitoring of excreted 4,4'-methylenedianiline in urine, during epicutaneous skin hypersensitivity testing (patch testing).