Benzidine. Determination in workplace air

Abstract

Benzidine is a white, crystalline solid. In the past, it was used mainly for the production of dyes, and nowadays in chemical analysis. Benzidine can cause bladder cancer to humans. The aim of this study was to develop a method for determining benzidine in workplace air, which will makes it possible to determine its concentrations at the lowest possible level. The method is based on the chemisorption of benzidine on a glass fiber filter treated with sulphuric acid(VI), extraction of benzidine disulphate with water and sodium hydroxide solution, and after extraction to the solid phase (SPE), benzidine is eluted from the SPE cartridge using 1 mL of methanol. The obtained solution is analyzed chromatographically. The tests were performed using a liquid chromatograph (HPLC) 1200 series of Agilent Technologies with a fluorescence detector (FLD). Determinations were performed using an Ultra C18 column (25 cm × 4.6 mm, dp = 5 µm). The procedure was validated according to Standard No. EN 482. The method can be used to determine benzidine in workplace air in the concentration range from 0.1 to 2 µg/m3. The limit of quantification (LOQ) is 0.25 ng/m3. The overall accuracy of the method was 5.36% and its relative total uncertainty was 23%. This method makes it possible to selectively determine benzidine in workplace air in the presence of most substances that do not show fluorescence, and in the presence of: biphenyl-4-amine, 1-naphthylamine and 2-naphthylamine, which show fluorescence. The method of determining benzidine has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.