Investigation Of Methods To Determine Urinary S-phenylmercapturic Acid For Occupational Exposure Workers To Benzene

ObjectiveThe phenol, S-phenylmercapturic acid (SPMA), trans,trans-muconic acid(ttMA)and benzene in blood are considered biomarkers of occupational exposure to benzene at present. The urinary SPMA and ttMA are considered sensitive biomarkers occupational exposure to low level of benzene. Urinary SPMA does not have interference from other kinds of metabolites .Accordingly ,the application value of urinary SPMA as biomonitoring is superior than urinary phenol and ttMA. Recently,part of the developed countries chose urinary SPMA to be one of the biomarkers of occupational benzene exposure,to raise the biological limit value of urinary SPMA corresponding the occupational air benzene level of there own countries.Research for biomarkers of benzene in our country is at preliminary stage.This research established the methods of determining SPMA in urine to provide the experimental methods for the biological limit value of urinary SPMA.Methods20 students of no occupational exposure to benzene and non-smokers were chosen to be ground substance of urine sample, preparing the standard solution with SPMA concentration 2000,1000,500,250,125,62.5,40μg/L and 320,160,80,40,20,10μg/L . Use HPLC/UV and HPLC/MS methods to analyze urinary SPMA.ResultThe HPLC/UV analytical method: The limit of detection was 40μg/L, linearity in a range from 40 to 2000μg/L. The intra-day and inter-day precisions(RSD) for the analysis were 2.43%～14.48% and 3.75%～9.23%,respectively. The average recovery rate ranged from 92.64%～103.66%.The HPLC/MS analytical method: The method showed good linearity in a range from 10 to 320μg/l and the limit of detection was 5μg/L, the equation of linear regressionthe was Y=1841.6X+19538,correlation coefficient was r=0.9994 (R2=0.9989).The average recovery rate ranged from 93.86% to 104.33%.The intra-day and inter-day precisions(RSD) for the analysis were 1.97%～7.96% and 2.72%～8.57%,respectively.A good linear relationship was shown between the results of the two methods when the concentration of samples above 40μg/L.ConclusionHPLC/UV and HPLC/MS methods can determine urinary SPMA, A good linear relationship was shown between the results of the two methods when the concentration of samples above 40μg/L.Both methods can provide the experimental methods for the biological limit value of urinary SPMA—occupational exposure to benzene.