Determination of 15 Biomarkers of Endocrine Disrupting Chemicals in Human Saliva by Gas Chromatography–Mass Spectrometry

Abstract

A sensitive method was developed to simultaneously determine 15 biomarkers of endocrine disrupting chemicals (EDCs) in human saliva using dispersive liquid-liquid microextraction (DLLME) and gas chromatography-mass spectrometry. This study also confirmed that the phthalate diesters were converted by glucuronidase/aryl sulfatase to their respective primary metabolites -mono-esters, but not to the secondary metabolites. The amount of 100 μL β-glucuronidase/aryl sulfatase hydrolyzed about 95% of the phthalate diesters (500 μg/L) within 3 h. The problems of hydrolysis of phthalate diesters by β-glucuronidase/aryl sulfatase are discussed. Ethyl acetate and acetonitrile were selected as extraction and disperser solvents in DLLME, and then the extracts were subjected to derivatization with N-methyl-N-(tert-bultyl dimethyl silyl) trifluoroacetamide directly without concentration after extraction. After optimizing the required conditions, good linearity of analytes was achieved. The limit of detection (LOD) and the limit of quantification (LOQ) were in the ranges of 0.015-3.0 μg/L and 0.05-10 μg/L, respectively.

Compound-Specific 1D 1H NMR Pulse Sequence Selection for Metabolomics Analyses

“…These samples may include serum; plasma; urine; cell extracts; intestinal content; tissue; − plant seeds, flesh, leaves, stems, and roots; − and corals, algae, and jellyfish. − In high-resolution NMR spectroscopy, the focus is on the relational quantification of metabolites and estimation of metabolite concentrations in response to some perturbation. Metabolomics is used to observe relative quantitative changes and find out biomarkers. − Higher-dimensional NMR like pulse sequences of two-dimensional (2D) NMR is also used in metabolomics. − However, compared to a matching 1 H NMR data set, 2D NMR data-processing time is significantly shorter because the signal overlap is not a significant issue and deconvolution is not necessary …”

Ionic liquid-based aqueous biphasic systems as one-step clean-up, microextraction and preconcentration platforms for the improved determination of salivary biomarkers

“…To cope with these analytical constraints, deproteinization steps are commonly implemented throughout the analytical set-up. 9,10 Nevertheless, some of these steps do not follow the Green Chemistry requirements, as they usually involve the use of volatile hazardous solvents in tedious, lengthy, and energy-consuming procedures. Thus, it is urgent to develop methods that overcome the abovementioned sensitivity and instrumental compatibility challenges, while ensuring a simpler approach for the analysis of saliva.…”

Comprehensive identification of VX‐adducted plasma proteins using high‐resolution mass spectrometry

“…The high-resolution mass spectrometry-based proteomic profiling technique allows researchers to explore the proteome landscapes and their modifications of the complex biological samples such as tissue, urine, and blood. 6,7 Here, we investigated the VX-treated human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to discover a potential list of biomarkers for VX exposure. We carried out the bottom-up proteomics of VX-treated plasma and identified the VX targets along with reaction sites.…”