Abstract
Potential employee exposure to 3,3′-dichlorobenzidine (DCB) in textile operations may arise from residual amounts of DCB in certain pigments or by metabolic breakdown of these pigments. The sensitivity of an existing colorimetric method for measurement of DCB in urine was extended into the low ppb range. The method involves extraction of DCB from urine and its reaction with Chloramine-T. The detection of DCB by this method is linear over the range of 1–20 ppb. The linear regression calibration curve for a group of 44 control urines-containing 1–20 ppb of DCB had a relative standard deviation of 4.6%. The mean extraction recovery over this concentration range was 68%. Spectrophotometric scanning of the solution containing the color reaction product from urine concentrations as low as 1–2 ppb yielded spectra with distinguishable characteristic maxima. Such spectra potentially minimize the false-positive detection of DCB.