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München, Germany

Piller M.,ABF | Gilch G.,ABF | Scherer G.,ABF | Scherer M.,ABF
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

Urinary determination of nicotine metabolites provides an ideal tool for the quantitative assessment of the tobacco use-related nicotine dose, provided that the considered metabolites comprise a large share of the amount taken up. A method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the sensitive, fast and robust analysis of nicotine and 10 major nicotine metabolites ("Nic+10"), including cotinine, trans-3'-hydroxy-cotinine, nicotine- N-glucuronide, cotinine- N-glucuronide, trans-3'-hydroxy-cotinine- O-glucuronide, nornicotine, norcotinine, nicotine- N'-oxide, cotinine- N'-oxide and 4-hydroxy-(3-pyridyl)-butanoic acid. Corresponding deuterated internal standards were spiked prior to a simple and straightforward solid phase extraction (SPE) procedure. Liquid chromatography was performed on a reversed phase C8 column and mass-specific detection was conducted in scheduled-MRM mode. The method was validated according to FDA Guidelines, showing excellent selectivity, precision, accuracy and robustness. The limits of quantification were in the range 0.2-2.3. ng/ml for all analytes. The novel method was applied to human urine samples derived from 25 smoking subjects. Quantitative results were correlated against a previously used LC-MS/MS method and compared to reports from the literature. The relative molar profile of nicotine and its 10 major metabolites was in good agreement with the literature. In addition, correlation amongst the two methods was excellent for almost all analytes, whereas the accordance between both methods was moderate for hydroxy-cotinine- O-glucuronide and norcotinine. These deviations, however, could be explained. The current method allows the simultaneous determination of nicotine and its 10 major metabolites (metabolite coverage about 95% of the absorbed dose) from a small sample volume and within a reasonable amount of time. Due to its wide dynamic range, high sensitivity and high throughput capabilities, this method could serve as a powerful tool for quantifying the nicotine dose of smokers, passive smokers as well as novel tobacco and nicotine product users in clinical and epidemiological studies. © 2014 Elsevier B.V. Source

Pluym N.,ABF | Gilch G.,ABF | Scherer G.,ABF | Scherer M.,ABF
Analytical and Bioanalytical Chemistry

Abstract Mercapturic acids (MAs) are metabolic end products formed from conjugates between glutathione and electrophilic compounds. MAs are, therefore, suitable biomarkers of exposure to toxicants, which are either electrophiles by themselves or metabolized to electrophilic intermediates. We developed and validated two LC-MS/MS methods which allow the complementary, rapid, and sensitive determination of MAs derived from acrolein, acrylamide, acrylonitrile, benzene, 1,3-butadiene, crotonaldehyde, N,N-dimethylformamide, ethylene, ethylene oxide, vinyl chloride, propylene oxide, styrene, toluene as well as methylating and ethylating agents. Since separate determinations of single or small groups of MAs are time-consuming and expensive, we multiplexed several individual methods into two LC-MS/MS methods covering 18 individual mercapturic acids. Method validation according to FDA guidelines showed excellent results in terms of robustness, accuracy, and sensitivity of the methods. Moreover, the use of a minimal, simple, and straightforward sample cleanup procedure further accelerated the analytical workflow, which allows a time- and cost-efficient analysis of up to 18 MAs derived from various toxicants in environmental levels. The methods were applied to urine samples derived from a strictly diet-controlled clinical study, including 25 smoking and 25 non-smoking subjects. Significant increase in the urine concentrations in smokers as compared to non-smokers (p < 0.01; Student t test) was observed for 13 individual MAs. Moreover, a dose dependence was obtained for the majority of the analytes. In conclusion, the newly developed assays represent a powerful tool for the fast and reliable quantification of 18 MAs in clinical studies. A first method application suggests several suitable biomarkers for nine relevant toxicants in tobacco smoke. © 2015 Springer-Verlag Berlin Heidelberg. Source

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