Introduction: The WHO Study Group on Tobacco Product Regulation recommended a list of toxicants in mainstream smoke of cigarettes for mandated and recommended lowering. This list comprises 18 tobacco smoke constituents, including acrylonitrile, acetaldehyde, and formaldehyde. A reduction in exposure to those toxicants, through the use of new filters and tobacco technologies, can be assessed with suitable biomarkers of exposure measured in biofluids such as urine. However, no biomarkers for the smoking-related exposure to formaldehyde and acetaldehyde are available, whilst the dose response of cyanoethylvaline (CEMA), a urinary acrylonitrile biomarker has not been thoroughly characterized.

Objective: The objective of this project was to develop analytical methods for the determination of urinary CEMA, 2-methyl-thiazolidine-4-carbonyl-glycine (MTCG) (potential acetaldehyde biomarker), and thiazolidine-4-carbonylglycine (TCG) (potential formaldehyde biomarker), and evaluate the dose-response correlation with urinary nicotine.

Method: LC-MS/MS methods were developed, validated, and applied to a urine sample series obtained from non-smokers and smokers of 1 mg, 6 mg, and 10mg ISO-tar yield cigarettes. Nicotine and five of its metabolites were quantified to establish correlations with CEMA, TCG, and MTCG.

Results: The analytical method used for the determination of CEMA is sufficiently sensitive and specific to detect differences between smokers and non-smokers. Furthermore, urinary CEMA show a clear dose-response relationship to urinary nicotine. MTCG (0.72±0.45 ng/ml) and TCG (13.76±9.58 ng/ml) were detectable in human urine, but no correlation could be established with nicotine measured in the urine of smokers. The high TCG and MTCG background observed in non-smoker urine indicates the interference of possible confounding factors.