Trends in the application of high-resolution mass spectrometry for human biomonitoring: An analytical primer to studying the environmental chemical space of the human exposome

Abstract

Global profiling of xenobiotics in human matrices in an untargeted mode is gaining attention for studying the environmental chemical space of the human exposome. Defined as the study of a comprehensive inclusion of environmental influences and associated biological responses, human exposome science is currently evolving out of the metabolomics science. In analogy to the latter, the development and applications of high resolution mass spectrometry (HRMS) has shown potential and promise to greatly expand our ability to capture the broad spectrum of environmental chemicals in exposome studies. HRMS can perform both untargeted and targeted analysis because of its capability of full- and/or tandem-mass spectrum acquisition at high mass accuracy with good sensitivity. The collected data from target, suspect and non-target screening can be used not only for the identification of environmental chemical contaminants in human matrices prospectively but also retrospectively. This review covers recent trends and advances in this field. We focus on advances and applications of HRMS in human biomonitoring studies, and data acquisition and mining. The acquired insights provide stepping stones to improve understanding of the human exposome by applying HRMS, and the challenges and prospects for future research.

Synthesis and identification of deschloroketamine metabolites in rats' urine and a quantification method for deschloroketamine and metabolites in rats' serum and brain tissue using liquid chromatography tandem mass spectrometry

“…When the overall score was lower than 75%, the findings were excluded. Nevertheless, it is important to mention that the confirmation of the proposed metabolites in some cases was not possible as not all reference standards were available and only non‐targeted analysis was applied on urine samples.…”

“…Nevertheless, it is important to mention that the confirmation of the proposed F I G U R E 3 Synthesis of norDXE (14), trans-dihydroDXE-d 4 (16), and trans-dihydroDXE (17) and testing reduction of norDXE (14) suppression for at least some of analytes may occur. 52 Because of that the matrix-matched blank samples fortified with the synthesized standards were compared with data obtained for the real samples and with a mixture of synthesized standards dissolved in a plain solvent.…”

Mass defect filtering for suspect screening of halogenated environmental chemicals: A case study of chlorinated organophosphate flame retardants

“…On the contrary, the major limitation of MDF is that it probably yields more false positives because of the use of a relatively wider mass defect window (≥0.05 Da) than the targeted approaches with a much narrower window (≤0.01 Da). Hence, MDF, when used in combination with other data mining tools such as product ion and neutral loss filters, can not only take advantage of its strengths, but also overcome its limitations . In general, it is recommended to use multiple tools and instrumentation for the characterization of knowns and suspects in analytical workflows that rely on predicted molecular formulae and fragmentation patterns.…”

“…Given that the evidence that environmental transformation mechanisms are diverse, it is essential to apply suspect screening approaches to identify substitutes, replacements, and impurities, as well as their products and derivatives. Untargeted screening using high‐resolution mass spectrometers helps to collect the chemical signatures in a sample and make retrospective data interpretations possible . This is critical to study the adverse effects associated with their fate in the environment and on public health that happen on different time scales.…”

“…LC/QqTOF mass spectrometry was used to screen for organophosphate compounds in sludge and aqueous solutions, but MDF was not applied in these studies. Given the large amount of information generated in a QqTOF MS analysis, it is essential to apply appropriate filtering tools to look at specific groups of masses and, thus, to channel efforts in the subsequent identification of these as belonging to a specific chemical class of interest . The objective of this study was to apply MDF as a simplified data processing tool to filter out possible alternatives and derivatives of known Cl‐PFRs in the study of aqueous media.…”