Biomonitoring urinary pesticide metabolites in preschool children by supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry and their association with oxidative stress.

Investigating pesticide exposure and oxidative stress in preschool children is essential for elucidating the determinants of environmental health in early life, with human biomonitoring of urinary pesticide metabolites serving as a critical strategy for achieving this objective. This study demonstrated biomonitoring of 2 phenoxyacetic acid herbicides, 2 organophosphorus pesticide metabolites, and 4 pyrethroid pesticide metabolites in 159 preschool children and evaluated their association with oxidative stress biomarker 8-hydroxydeoxyguanosine. An enzymatic deconjugation process was used to release urinary pesticide metabolites, which were then extracted and enriched by supported liquid extraction, and quantified by ultra-high performance liquid chromatography-tandem mass spectrometry with internal standard calibration.

Association of co-exposure to polycyclic aromatic hydrocarbons and phthalates with oxidative stress and inflammation.

Exposure to multiple environmental pollutants is ubiquitous and inevitable, but studies investigating their exposure effects on oxidative stress or inflammation have mainly been restricted to single-pollutant models. This study investigated the association of co-exposure to polycyclic aromatic hydrocarbons and phthalates with oxidative stress and inflammation. Using a cross-sectional study in adults, we measured urinary concentrations of metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) and phthalates (mPAEs), urinary oxidative stress biomarker 8-hydroxy-2'-deoxyguanosine, and 9 inflammatory biomarkers in paired blood samples.

Association between polycyclic aromatic hydrocarbon exposure and blood lipid levels: the indirect effects of inflammation and oxidative stress.

Although previous studies have indicated polycyclic aromatic hydrocarbons (PAHs) as cardiovascular health risk factors, evidence linking exposure to PAHs and blood lipids is still lacking, and the mechanism remains largely unknown. In this study, we evaluated the association between human internal exposure to PAHs and blood lipid levels in adults, as well as the indirect effects of inflammation and oxidative stress. The internal exposure of PAHs was assessed by determining serum PAHs and their hydroxylated metabolites (OH-PAHs) in the paired urine samples.

Preparation of cationic hierarchical porous covalent organic frameworks for rapid and effective enrichment of perfluorinated substances in dairy products.

Perfluorinated substances (PFASs) are harmful pollutants that have environmental persistence and high bioaccumulation. Effective sample pretreatment must be performed to detect trace or even ultra-trace PFASs in actual samples because of their extremely low contents in complex samples. In this study, a cationic hierarchical porous covalent organic frameworks (C-H-COF) were customized via a template-assisted strategy using polystyrene spheres (PS) as sacrificial materials and a post-synthetic modification method.

Community evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through air.

Background: Nine COVID-19 (Corona Virus Disease, 2019) cases were observed in one community in Guangzhou. All the cases lived in three vertically aligned units of one building sharing the same piping system, which provided one unique opportunity to examine the transmission mode of SARS-CoV-2.

Methods: We interviewed the cases on the history of travelling and close contact with the index patients.

Ultra-high performance liquid chromatography tandem mass spectrometry for the determination of five glycopeptide antibiotics in food and biological samples using solid-phase extraction.

This paper demonstrated the development and validation of an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of five glycopeptide antibiotics in food and biological samples. The target glycopeptide antibiotics were isolated from the samples by solvent extraction, and the extracts were cleaned with a tandem solid-phase extraction step using mixed strong cation exchange and hydrophilic/lipophilic balance cartridges. Subsequently, the analytes were eluted with different solvents, and then quantified by UHPLC-MS/MS in the positive ionization mode with multiple reaction monitoring.

Determination of 19 sulfonamides residues in pork samples by combining QuEChERS with dispersive liquid-liquid microextraction followed by UHPLC-MS/MS.

A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid-liquid microextraction followed by ultra-high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid-liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent that obtained by QuEChERS. The enriched tetrachloroethane organic phase by dispersive liquid-liquid microextraction was evaporated, reconstituted with 100 μL acetonitrile/water (1:9 v/v) and injected into an ultra-high performance liquid chromatography with a mobile phase composed of acetonitrile and 0.

Antibody-free ultra-high performance liquid chromatography/tandem mass spectrometry measurement of angiotensin I and II using magnetic epitope-imprinted polymers.

The major challenges in measuring plasma renin activity (PRA) stem from the complexity of biological matrix, as well as from the instability and low circulating concentration of angiotensin. In this study, an ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) based technique has been developed for the measurement of angiotensin using magnetically imprinted polymers for simultaneous enrichment of the precursor peptide angiotensin II (Ang II) and the upstream peptide precursor angiotensin I (Ang I). This technique involved surface graft imprinting in aqueous solutions using vinyl-modified nano-iron oxide as solid supports, the specificity determinant of Ang I and Ang II as the epitope, and methacrylic acid and N-t-butylacrylamide as functional monomers.

Development of hybrid organic-inorganic surface imprinted Mn-doped ZnS QDs and their application as a sensing material for target proteins.

Applying molecular imprinting techniques to the surface of functionalized quantum dots (QDs) allows the preparation of molecularly imprinted polymers (MIPs) with accessible, surface exposed binding sites and excellent optical properties. This paper demonstrates a new strategy for producing such hybrid organic-inorganic imprinted Mn-doped ZnS QDs for specific recognition of bovine hemoglobin. The technique provides surface grafting imprinting in aqueous solutions using amino modified Mn-doped ZnS QDs as supports, acrylamide and methacrylic acid as functional monomers, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and bovine hemoglobin as a template.

Determination of 23 organophosphorous pesticides in surface water using SPME followed by GC-MS.

Determination of 23 organophosphorous pesticides (sulfotep, phorate, demeton, diazinon, disulfoton, kitazzin.P, chlorpyrifos-methyl, methyl-parathion, ronnel, fenitrothion, malathion, chlorpyrifos, fenthion, parathion, bromophos, isofenphos-methyl, phenthoate, quinalphos, ethion, triazophos, carbophenothion, pirimiphos-methyl, and pirimiphos-ethyl) in water using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry detection (GC-MS) was investigated. The influence of various parameters on pesticides extraction efficiency by SPME was thoroughly studied.

[Lead levels in children after 10-year use of unleaded gasoline in Guangzhou municipality].

Objective: To investigate the blood lead levels (BLLs) in children after 10-year use of unleaded gasoline in Guangzhou and evaluate the effect of this measure.

Methods: Through stratified random sampling method, 4 kindergartens and 4 elementary schools were selected from each of three districts among 12 districts of Guangzhou. Totally 2373 children were recruited into this survey and 1-2 ml blood was sampled from each child through vein.

[Application of AOTF in spectral analysis. 4. Enhancing spectral resolution of AOTF atomic emission spectrometer with FSD].

Using Fourier self-deconvolution (FSD) to enhance spectral resolution of AOTF atomic emission spectrometer is described. Choosing the appropriate deconvolution parameters: full width at half maximum (FWHM) and breaking point, the FWHM of the simulated overlapping peaks could be decreased by a factor of 3.5, and the peak height by a factor of 5, but retaining the peak position.

[Application of AOTF in spectral analysis. 2. Application of self-constructed visible AOTF spectrophotometer].

The performances of a self-constructed visible AOTF spectrophotometer are presented. The wavelength calibration of AOTF1 and AOTF2 are performed with a didymium glass using a fourth-order polynomial curve fitting method. The absolute error of the peak position is usually less than 0.

[Application of AOTF in spectral analysis. 1. Hardware and software designs for the self-constructed visible AOTF spectrophotometer].

A self-constructed visible spectrophotometer using an acousto-optic tunable filter(AOTF) as a dispersing element is described. Two different AOTFs (one from The Institute for Silicate (Shanghai, China) and the other from Brimrose(USA)) are tested. The software written with visual C++ and operated on a Window98 platform is an applied program with dual database and multi-windows.

[Application of AOTF in spectral analysis. 3. Application of AOTF in atomic emission spectral analysis].

An atomic emission spectrometer based on acousto-optic tunable filter (AOTF) was self-constructed and was used to evaluate its practical use in atomic emission analysis. The AOTF used was of model TEAF5-0.36-0.