Analysis of 4-aminobiphenyl in smoker’s and nonsmoker’s urine by tandem mass spectrometry

Abstract

The aromatic amine 4-aminobiphenyl (4-ABP) is present in tobacco smoke. In humans, it is also a known bladder carcinogen. We describe here a method for the quantification of total 4-ABP in urine using capillary gas chromatography/tandem mass spectrometry, with an effective detection limit in urine samples of approximately 0.87 pg/mL. We also examined the efficiency of chemical or enzymatic hydrolysis of urinary aromatic amine metabolites. Although we found acidic or basic hydrolysis effective, we found enzymatic hydrolysis (β-glucuronidase with either Escherichia coli or Helix pomatia) ineffective. As part of this work, we also confirm the presence of N-acetyl-4-ABP and 4-ABP glucuronide in human urine samples from smokers. These metabolites have been reported in animal studies, but previously they have not been identified in human samples. These metabolites, however, were found to be unstable and thus infeasible for biomonitoring. The final validated urinary total 4-ABP assay was applied to the analysis of samples from smokers and nonsmokers, whose status was confirmed from cotinine EIA measurements. Among 41 confirmed nonsmokers, the geometric mean (95% CI) of 4-ABP concentration was 1.64 pg/mg creatinine (1.30–2.07). Conversely, in 89 smokers, the geometric mean of 4-ABP concentration was significantly greater, at 8.69 pg/mg creatinine (7.43–10.16), p < 0.001. Our results indicate that following tobacco smoke exposure, total urinary 4-ABP is a reliable biomarker for exposure to this carcinogen.

Keywords::

• Chemical carcinogenesis
• tobacco science
• mass spectroscopy

Acknowledgements

We thank Connie Sosnoff and Kay DeLong (Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention) for assistance with the urine cotinine immunoassay analysis, and Pamela G. Olive (Clinical Chemistry Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention) for assistance with the creatinine measurements. We also thank Dr. Ram Jain for his statistical analysis.

Declaration of interest

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. Use of trade names and commercial sources is for identification only and does not constitute endorsement by the U.S. Department of Health and Human Services or the Centers for Disease Control and Prevention.