Determination of a specific metabolite for the non-ionic surfactant 2,4,7,9-Tetramethyl-5-decyne-4,7-diol (TMDD) by UPLC-MS/MS.

2,4,7,9-Tetramethyldec-5-yne-4,7-diol (TMDD) is a non-ionic surfactant commonly used as defoaming agent and numerous other applications. Effluents of wastewater treatment plants have been identified as one of the main sources of TMDD emissions into the environment. Due to its broad application in various fields, TMDD was selected for the development of a biomonitoring method for assessing human exposure within the frame of the cooperation project of the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) and the German Chemical Industry Association (VCI) in 2020. This study aimed to identify a urinary metabolite for TMDD by UPLC-Q-Orbitrap-MS which can be used as a biomarker of TMDD exposure. Monohydroxylated TMDD (1-OH-TMDD) was deciphered as the most prominent metabolite of TMDD in humans in a series of in vitro and in vivo experiments. In a next step, a quantitative method for the determination of 1-OH-TMDD was developed and validated. Quantification was achieved by isotope dilution using D3-1-OH-TMDD as internal standard. The method is characterized by a simple sample clean-up procedure and an enzymatic hydrolysis of possible metabolite conjugates with ß-glucuronidase. Method validation was performed according to international guidelines for bioanalytical method validation. The method proved its robustness, precision, accuracy and sensitivity for the intended purpose, i.e. the assessment of TMDD exposure in the general population by means of human biomonitoring.

Identification of biomarkers specific to five different nicotine product user groups: Study protocol of a controlled clinical trial.

BACKGROUND: Assessing biomarker profiles in various body fluids is of large value to discern between the sole use of nicotine products. In particular, the assessment of the product compliance is required for long-term clinical studies. The objective of this study was the identification of biomarkers and biomarker patterns in body fluids, to distinguish between combustibles, heated tobacco products, electronic cigarettes, oral tobacco and oral/dermal nicotine products used for nicotine replacement therapy (NRT), as well as a control group of non-users. METHODS: A controlled, single-center study was conducted with 60 healthy subjects, divided into 6 groups (5 nicotine product user groups and one non-user group) based on their sole use of the products of choice. The subjects were confined for 76 h, during which, free and uncontrolled use of the products was provided. Sample collections were performed according to the study time schedule provided in Table 2. The primary outcome will be validated through analysis of the collected biospecimens (urine, blood, saliva, exhaled breath and exhaled breath condensate) by means of untargeted omics approaches (i.e. exposomics, breathomics and adductomics). Secondary outcome will include established biomarker quantification methods to allow for the identification of typical biomarker patterns. Statistical analysis tools will be used to specifically discriminate different product use categories. RESULTS/CONCLUSIONS: The clinical trial was successfully completed in May 2020, resulting in sample management and preparations for the quantitative and qualitative analyses. This work will serve as a solid basis to discern between biomarker profiles of different nicotine product user groups. The knowledge collected during this research will be required to develop prototype diagnostic tools that can reliably assess the differences and evaluate possible health risks of various nicotine products.