National Institute for Occupational Safety and Health

“ There is also some risk from the chemical content of these samples, but this is much less. Those who handle urine specimens should wear protective gloves, and avoid aerosolization of the samples. Mouth pipetting, of course, must be avoided. Benzidine and benzene are documented human carcinogens and must be handled in compliance with 29 CFR 1910.1005 and 1910.1028. ”

“ Dissolve 136 g KH 2PO 4 in 900 mL H2O. Adjust to pH 6 with 10 N NaOH. Dilute to 1 L with H 20 and extract once with 100 mL benzene. 14. Paraffin oil. 15. Heptafluorobutyric anhydride. 16. Nitrogen gas, compressed, purified.
See SPECIAL PRECAUTIONS.
SPECIAL PRECAUTIONS: Samples of urine collected from humans pose a real health risk to laboratory workers who collect and handle these samples. These risks are primarily due to personal contact with infective biological samples and can have serious health consequences, such as infectious hepatitis, and other diseases. ”

“ Add aliquots of benzidine stock solution to 1.5 mL benzene and 0.5 mL trimethylamine working solution. b. Perform steps 12 and 13. c. Percolate the benzene layer through 2 cm anhydrous sodium sulfate. d. Add 0.5 mL derivatized methylenedianiline stock solution. e. Dilute to 10.0 mL with benzene. f. Analyze the working standards together with samples and blanks (step 21 and 22) . g. Prepare calibration graph (concentration of standards vs. ratio of peak areas of benzidine to methylenedianiline) . Analyze a spiked urine for every 10 samples (minimum three per study) . ”