ANILINE and @-TO LUIDIN E in urine: MET HO D 831 7, Issue 1, dated 15 M arch 200 3 - Page 5 o f 6 30. Measure peak heights of aniline and @-toluidine in the calibration solutions a nd in the sa m ples. 31. Peak purity can be confirmed, if necessary, by re-analyzing the extract and three calibration solutions, once with Electrode 2 set at 520 mV and once at 600 mV. The response ratios of the unknown at these two voltages should match the response ratio of the calibration solutions within ± 3 standard deviations. 32. If the sample gives a peak for aniline and @-toluidine with a peak height out of the calibration range, re-analyze the extract using a 5 µL injection. If the 5 µL injection still gives a peak out of the calibration range, reduce the detector gain.
CALCULATIONS: 33. Calculate the concentration, C(pg/:L), of aniline or @-toluidine in the unknow n from the peak heigh ts and the calibration curve for aniline or @-toluidine , resp ective ly (C, :g/L).
a, b, c, and Y are defined in step 21 D = :L of injection volume E = initial volume of urine F = volum e of 0 .1 M HC l back extra ctan t G = initial volume of butyl chloride H = transferred volume of butyl chloride This equation does not account for a change in detector gain.
GUIDES TO INTERPRETATION: This method was applied to 171 urine specimens from a chemical plant worker population with a know n exces s of bladder can cer. The m edian levels of @-toluidine were: expos ed p reshift = 11 :g/L; exposed postshift = 65 :g/L; nonexposed preshift = 0.7 :g/L; and n one xpo sed pos tshift = 2.6 :g/L. The m edian levels of aniline were: exposed preshift = 11 :g/L; expo sed pos tshift = 23 :g/L; nonexposed preshift = 2.0 :g/L; and nonexposed postshift = 3.2 :g/L. [4-8] The Karam El-Bayoumy et al. study [3] reported the total mass of aniline and @-toluidine excreted by urine of 19 occ upa tionally exp ose d su bjec ts, and they found that the work ers exc reted from 0.02 to 8.8 :g of aniline and 0.3 to 12.9 :g of @-toluidine during a 24-hour period.
EVALUATION OF METHOD: The American Conference of Governmental Industrial Hygienists has recom m ended a biological expos ure index (BEI) for aniline of 50 mg of 4-aminophenol per milligram of creatinine, measured in end-of-shift urine specimens. 4-Am inophen ol is the ring hydroxylated m etab olite of aniline [1]. Before a BE I for @-toluidine can be established, a relationship between exposure to o-toluidine and excretion of the metabolite must be established. Rat studies sugg est that @-toluid ine is also substantially metabolized by a ring hydroxylation pathw ay, but no one has dem ons trated the presenc e of th e m etab olite in the u rine of hum ans exp ose d to o-toluidine [2]. Other xenobiotics, I.e.. acetoaminophen, reach the same m eta bolic fate of 4-aminophenol as does aniline. T his m etho d, m onitors the parent compounds and their acetyl metabolites to remove the ambiguity from the aminophenol’s origin. The method was characterized during a field study that included 45 batches of samples. Each batch contained QC sam ples of aniline with no m inal levels of aniline sp iked at 6.9 ng/m L, 18 ng/m L, and 77 ng/m L and with nom inal levels of @-toluidine spiked at 4.2 n g/m L, 20 ng/m L, and 10 2 ng /m L. QCs sam lpes were also made using aceta nilide and N-acetyl-@-toluidine spiked to an equivalent free am ine co nce ntration of 19 ng/m L NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
