In silico deconjugation of glucuronide conjugates enhances tandem mass spectra library annotation of human samples

Pesticide residues and polyphenols in urine - A combined LC-HRMS screening to reveal intake patterns

Human exposure to pesticides in the general population occurs mainly through food consumption. However, specific dietary habits or food products that contribute to pesticide exposure are often unknown. In this study, we propose a combined screening for polyphenols and pesticide residues by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) to assess the diet and the associated pesticide exposure. We measured 587 urine samples from women around the 34th week of pregnancy of a prospective mother-child cohort. A non-targeted screening for flavonoid-like compounds related to fruit and vegetable consumption was performed, prioritizing 164 features and identifying a total of 46 features by spectral library search. Based on a subset of markers, k-means clustering was performed, leading to four clusters with presumably similar dietary habits. The clusters were compared against food questionnaire data collected within the period of sample collection. Suspect screening of more than 500 pesticide residues including metabolites was performed, with a total of 40 residues being reported for 27 different pesticides. The detection of pesticide residues was compared across the different clusters of dietary habits. Indications were found that pyrimethanil metabolites might be associated with the consumption of citrus fruits or derivate products. We demonstrate that the method used has the potential to reveal patterns of pesticide intake from specific food commodities.

Insights into the human metabolism of hexahydrocannabinol by non-targeted liquid chromatography-high-resolution tandem mass spectrometry

Hexahydrocannabinol (HHC), 6,6,9-trimethyl-3-pentyl-6a,7,8,9,10,10a-hexahydrobenzo[c]chromen-1-ol, is a semi-synthetic cannabinoid that has presented challenges to analytical laboratories due to its emergence and spread in the drug market. The lack of information on human pharmacokinetics hinders the development and application of presumptive and confirmatory tests for reliably detecting HHC consumption. To address this knowledge gap, we report the analytical results obtained from systematic forensic toxicological analysis of body-fluid samples collected from three individuals suspected of drug-impaired driving after HHC consumption. Urine and plasma samples were analyzed using non-targeted liquid chromatography-high-resolution tandem mass spectrometry. The results provided evidence that HHC undergoes biotransformation reactions similar to other well-characterized cannabinoids, such as ∆9-tetrahydrocannabinol or cannabidiol. Notably, HHC itself was only detectable in plasma samples, not in urine samples. The observed Phase I reactions involved oxidation of C11 and the pentyl side chain, leading to corresponding hydroxylated and carboxylic acid species. Additionally, extensive glucuronidation of HHC and its Phase I metabolites was evident.

How Wastewater Reflects Human Metabolism─Suspect Screening of Pharmaceutical Metabolites in Wastewater Influent

Pharmaceuticals and their human metabolites are contaminants of emerging concern in the aquatic environment. Most monitoring studies focus on a limited set of parent compounds and even fewer metabolites. However, more than 50% of the most consumed pharmaceuticals are excreted in higher amounts as metabolites than as parents, as confirmed by a literature analysis within this study. Hence, we applied a wide-scope suspect screening approach to identify human pharmaceutical metabolites in wastewater influent from three Swiss treatment plants. Based on consumption amounts and human metabolism data, a suspect list comprising 268 parent compounds and over 1500 metabolites was compiled. Online solid phase extraction combined with liquid chromatography coupled to high-resolution tandem mass spectrometry was used to analyze the samples. Data processing, annotation, and structure elucidation were achieved with various tools, including molecular networking as well as SIRIUS/CSI:FingerID and MetFrag for MS2 spectra rationalization. We confirmed 37 metabolites with reference standards and 16 by human liver S9 incubation experiments. More than 25 metabolites were detected for the first time in influent wastewater. Semiquantification with MS2Quant showed that metabolite to parent concentration ratios were generally lower compared to literature expectations, probably due to further metabolite transformation in the sewer system or limitations in the metabolite detection. Nonetheless, metabolites pose a large fraction to the total pharmaceutical contribution in wastewater, highlighting the need for metabolite inclusion in chemical risk assessment.

The role of sample preparation in suspect and non-target screening for exposome analysis using human urine

The use of suspect and non-target screening (SNTS) for the characterization of the chemical exposome employing human biofluids is gaining attention. Among the biofluids, urine is one of the preferred matrices since organic xenobiotics are excreted through it after metabolization. However, achieving a consensus between selectivity (i.e. preserving as many compounds as possible) and sensitivity (i.e. minimizing matrix effects by removing interferences) at the sample preparation step is challenging. Within this context, several sample preparation approaches, including solid-phase extraction (SPE), liquid-liquid extraction (LLE), salt-assisted LLE (SALLE) and dilute-and-shoot (DS) were tested to screen not only exogenous compounds in human urine but also their phase II metabolites using liquid-chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS). Additionally, enzymatic hydrolysis of phase II metabolites was evaluated. Under optimal conditions, SPE resulted in the best sample preparation approach in terms of the number of detected xenobiotics and metabolites since 97.1% of the total annotated suspects were present in samples extracted by SPE. In LLE and SALLE, pure ethyl acetate turned out to be the best extractant but fewer suspects than with SPE (80.7%) were screened. Lastly, only 52.5% of the suspects were annotated in the DS approach, showing that it could only be used to detect compounds at high concentration levels. Using pure standards, the presence of diverse xenobiotics such as parabens, industrial chemicals (benzophenone-3, caprolactam and mono-2-ethyl-5-hydroxyhexyl phthalate) and chemicals related to daily habits (caffeine, cotinine or triclosan) was confirmed. Regarding enzymatic hydrolysis, only 10 parent compounds of the 44 glucuronides were successfully annotated in the hydrolysed samples. Therefore, the screening of metabolites in non-hydrolysed samples through SNTS is the most suitable approach for exposome characterization.

Immobilised-enzyme microreactors for the identification and synthesis of conjugated drug metabolites

The study of naturally circulating drug metabolites has been a focus of interest, since these metabolites may have different therapeutic and toxicological effects compared to the parent drug. The synthesis of metabolites outside of the human body is vital in order to conduct studies into the pharmacological activities of drugs and bioactive compounds. Current synthesis methods require significant purification and separation efforts or do not provide sufficient quantities for use in pharmacology experiments. Thus, there is a need for simple methods yielding high conversions whilst bypassing the requirement for a separation. Here we have developed and optimised flow chemistry methods in glass microfluidic reactors utilising surface-immobilised enzymes for sulfonation (SULT1a1) and glucuronidation (UGT1a1). Conversion occurs in flow, the precursor and co-factor are pumped through the device, react with the immobilised enzymes and the product is then simply collected at the outlet with no separation from a complex biological matrix required. Conversion only occurred when both the correct co-factor and enzyme were present within the microfluidic system. Yields of 0.97 ± 0.26 μg were obtained from the conversion of resorufin into resorufin sulfate over 2 h with the SULT1a1 enzyme and 0.47 μg of resorufin glucuronide over 4 h for UGT1a1. This was demonstrated to be significantly more than static test tube reactions at 0.22 μg (SULT1a1) and 0.19 μg (UGT1a1) over 4 h. With scaling out and parallelising, useable quantities of hundreds of micrograms for use in pharmacology studies can be synthesised simply.

Wastewater-based epidemiology for the assessment of population exposure to chemicals: The need for integration with human biomonitoring for global One Health actions

WBE has now become a complimentary tool in SARS-CoV-2 surveillance. This was preceded by the established application of WBE to assess the consumption of illicit drugs in communities. It is now timely to build on this and take the opportunity to expand WBE to enable comprehensive assessment of community exposure to chemical stressors and their mixtures. The goal of WBE is to quantify community exposure, discover exposure-outcome associations, and trigger policy, technological or societal intervention strategies with the overarching aim of exposure prevention and public health promotion. To achieve WBE's full potential, the following key aspects require further action: (1) Integration of WBE-HBM (human biomonitoring) initiatives that provide comprehensive community-individual multichemical exposure assessment. (2) Global WBE monitoring campaigns to provide much needed data on exposure in low- and middle-income countries (LMICs) and fill in the gaps in knowledge especially in the underrepresented highly urbanised as well as rural settings in LMICs. (3) Combining WBE with One Health actions to enable effective interventions. (4) Advancements in new analytical tools and methodologies for WBE progression to enable biomarker selection for exposure studies, and to provide sensitive and selective multiresidue analysis for trace multi-biomarker quantification in a complex wastewater matrix. Most of all, further developments of WBE needs to be undertaken by co-design with key stakeholder groups: government organisations, health authorities and private sector.

A large scale multi-laboratory suspect screening of pesticide metabolites in human biomonitoring: From tentative annotations to verified occurrences

Within the Human Biomonitoring for Europe initiative (HBM4EU), a study to determine new biomarkers of exposure to pesticides and to assess exposure patterns was conducted. Human urine samples (N = 2,088) were collected from five European regions in two different seasons. The objective of the study was to identify pesticides and their metabolites in collected urine samples with a harmonized suspect screening approach based on liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) applied in five laboratories. A combined data processing workflow included comprehensive data reduction, correction of mass error and retention time (RT) drifts, isotopic pattern analysis, adduct and elemental composition annotation, finalized by a mining of the elemental compositions for possible annotations of pesticide metabolites. The obtained tentative annotations (n = 498) were used for acquiring representative data-dependent tandem mass spectra (MS2) and verified by spectral comparison to reference spectra generated from commercially available reference standards or produced through human liver S9 in vitro incubation experiments. 14 parent pesticides and 71 metabolites (including 16 glucuronide and 11 sulfate conjugates) were detected. Collectively these related to 46 unique pesticides. For the remaining tentative annotations either (i) no data-dependent MS2 spectra could be acquired, (ii) the spectral purity was too low for sufficient matching, or (iii) RTs indicated a wrong annotation, leaving potential for more pesticides and/or their metabolites being confirmed in further studies. Thus, the reported results are reflecting only a part of the possible pesticide exposure.