Search

Antibiotics and pesticides are widespread in most rivers and lakes due to the overuse of antibiotics and pesticides, but there are few methods for simultaneous analysis of antibiotics and pesticides in aquatic environments. To address this knowledge gap, a concise and sensitive analytical method is proposed in which three classes of human and veterinary drugs (sulfonamides, macrolides, and hormones) and two classes of pesticides (organophosphorus and neonicotinoids) are simultaneously extracted and determined in surface water. The solid-phase extraction column with Cleanert PEP-2 was preconditioned sequentially with 6 mL of methanol, ultrapure water, and citric acid buffer (pH 3.0) each for simultaneous extraction and further purification. The forty-seven target analytes were analysed by LC-MS/MS in positive and negative ion modes. The LC separation was performed using a Sigma-Aldrich C18 column with 0.1% formic acid in water and acetonitrile as a gradient eluting mobile phase in positive ion mode. The internal standard method was used to overcome the inevitable matrix effects in LC-MS/MS analysis. The matrix effects of most target analytes were in the range of 27–151%. The recoveries of forty analytes in the three concentrations (10, 50, and 100 ng L−1) of surface water spiked samples ranged from 41 to 127%. The method quantitative limits of the analytes were in the range of 0.40–5.49 ng L−1. Application of the method to analyze samples in the eight runoff outlets of the Pearl River Delta showed that some antibiotics and pesticides were detected, and the concentration of parathion was as high as 154 ng L−1. A powerful tool for quickly and efficiently screening for contaminants in surface water has been presented. [ABSTRACT FROM AUTHOR]

Context: Inflammation plays a critical role in the development and progression of obstructive sleep apnea (OSA). Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) activation is involved in the pathophysiology of inflammatory process-related disorders. Objective: This study aims to investigate whether serum soluble LOX-1 (sLOX-1) levels are associated with the presence and severity of OSA. Materials and Methods: A total of 137 OSA patients and 78 controls were recruited in this study. Serum sLOX-1 levels were measured by enzyme-linked immunosorbent assay. The severity of OSA was assessed by the apnea-hypopnea index (AHI). Results: OSA patients had significantly higher serum sLOX-1 levels compared with controls. Serum sLOX-1 levels elevated with the increment of OSA severity. sLOX-1 was the independent predictor of OSA. Serum sLOX-1 levels were significantly correlated with AHI and high-sensitivity C-reactive protein levels. Conclusions: Serum sLOX-1 levels were independently correlated with the presence and severity of OSA. These findings revealed that sLOX-1 might function as a potential biomarker for monitoring the development and progression of OSA. [ABSTRACT FROM AUTHOR]

The current study investigates GaN-based light-emitting diodes (LEDs) with InGaN/GaN/InGaN multi-layer barrier (MLB). Simulation results show that GaN-based LEDs with MLB have better performance than conventional GaN-based LEDs with only one GaN barrier because of the enhancement in hole injection into the quantum well and decrease in electron leakage current. [ABSTRACT FROM AUTHOR]

Abstract: Sau3AI is a type II restriction enzyme that recognizes the 5′-GATC-3′ sequence in double-strand DNA and cleaves at 5′ to the G residue. The C-terminal domain of Sau3AI (Sau3AI-C), which contains amino acids from 233 to 489, was crystallized and its structure was solved by using the Multi-wavelength Anomalous Diffraction method. The Sau3AI-C structure at 1.9 Å resolution is similar to the structure of MutH, a DNA mismatch repair protein that shares high sequence similarity with the N-terminal Sau3AI domain. The functional analysis shows that Sau3AI-C can bind DNA with one recognition sequence but has no cleavage activity. These results indicate that Sau3AI is a pseudo-dimer belonging to the type IIe restriction enzymes and the Sau3AI-C is the allosteric effector domain that assists DNA binding and cleavage. [Copyright &y& Elsevier]

A low-cost porous bimetallic hybrid electrocatalyst (Ni/Mo 6 Ni 6 C@C nanoparticle) has been synthesized via a soft-template using Polyethylenimine (PEI), Polyoxometalate (POM) and metal ion as precursors. • The bimetallic catalysts Ni/Mo 6 Ni 6 C@C were synthesized by a soft-template method. • The intermolecular forces in precursors are the basis of forming Ni/Mo 6 Ni 6 C@C. • Ni/Mo 6 Ni 6 C@C exhibited excellent catalytic activity and durability for HER. • DFT calculations pinpoint the origin of the excellent performance of Ni/Mo 6 Ni 6 C@C. Hydrogen generated by water splitting devices is a promising way to solve energy issues, which is limited by Pt-based precious catalysts. Developing efficient Pt-free electrocatalyst for hydrogen evolution reaction (HER) is highly essential for the practical applications. Herein, we report a soft-template method to fabricate an efficient porous bimetallic hybrid material, dubbed Ni/Mo 6 Ni 6 C@C. Benefiting from the bimetallic feature and porous structure, Ni/Mo 6 Ni 6 C@C exhibits low overpotentials of 101 and 122 mV at 10 mA cm−2 with robust stability in alkaline and acidic media, respectively. Theoretical calculations demonstrate that the C sites of the Mo 6 Ni 6 C possess the most excellent electrocatalytic activity due to its Gibbs free energy of hydrogen adsorption closer to 0 eV. Moreover, the superior stability, metallic character and mechanical property are characterized by first-principles calculations, which are advantageous for the Mo 6 Ni 6 C to be the HER catalyst. This study supplies a concise strategy to prepare the highly efficient bimetallic electrocatalyst for HER. [ABSTRACT FROM AUTHOR]

A novel chiral derivatization reagent, the N‐[1‐oxo‐5‐(triphenylphosphonium)pentyl]‐ (R)‐1,3‐thiazolidinyl‐4‐N‐hydroxysuccinimide ester bromide salt (OTPTHE), was developed for the separation and selective detection of chiral DL‐amino acids by RP‐HPLC analysis. The OTPTHE reacted with DL‐amino acids at 60°C maintained for 30 minutes in the presence of 100 mM borate buffer (pH 9.5). The separability of the diastereomeric derivatives was evaluated in terms of the resolution value (Rs) using 13 kinds of DL‐amino acids, which were completely separated by reversed‐phase chromatography using C18 column at 254 nm. The Rs of the DL‐amino acids varied from 1.62 to 2.51. As for the application of the DL‐amino acids, the determination of DL‐Ser in the human plasma of healthy volunteers was performed based on our developed method. It was shown that linear calibrations were available with high coefficients of correlation (r2 > 0.9997). The limit of detection (S/N = 3) of the DL‐Ser enantiomers was 5.0 pmol; the relative standard deviations of the intraday and interday variations were below 4.56%; the accuracy ranged between 95.40%‐110.06% and 95.45%‐109.80%, respectively; the mean recoveries (%) of the DL‐Ser spiked in the human plasma were 99.49%‐103.74%. The amounts of DL‐Ser in the human plasma of healthy volunteers were determined. [ABSTRACT FROM AUTHOR]

A novel UHPLC–MS/MS method with high sensitivity and selectivity for simultaneous detection and chiral resolution of DL-amino acids in beer was established using the newly developed mass spectrometry probe (S)-(3-(4-carboxythiazolidin-3-yl)-3-oxopropyl) diphenylsulfonium (CTOD). The gradient analysis of five chiral amino acids (DL-Asp, DL-Glu, DL-Ala, DL-Pro, and DL-Phe) was carried out on a BEH C18 (2.1 × 150 mm, 1.7 μm) for 30 min with a mobile phase of 0.1% formic acid aqueous solution and 0.1% formic acid methanol/acetonitrile (7:3) solution. The resolutions of DL-amino acids ranged from 1.71 to 5.42. The correlation coefficients were ≥ 0.9994 in the range of 0.25 to 1200 pmol. Meanwhile, limits of detection (LOD) and limits of quantitative (LOQ) analysis were 0.05–0.25 pmol and 0.13–0.50 pmol, respectively. Furthermore, the intra-day and inter-day precision ranged from 0.34% to 6.31%, and the average recoveries ranged from 97.50% to 107.50%. The method was applied to the quantitative analysis and comparison of DL-amino acids in beer samples from 10 different manufacturers, and it was found that the beers were rich in D-amino acids. Four D-AAs including D-Ala, D-Pro, D-Glu, D-Phe (1.9–29.8 μmol L−1) and five L-AAs including L-Pro, L-Ala, L-Phe, L-Glu, L-Asp (5.3–2315.9 μmol L−1) were detected in the beer samples. The average content of L-AAs in the 10 beer samples was significantly higher than that of D-AAs. This study provides a new method for detecting chiral amino acids in beer and reliable data for evaluating the nutritional value of beer. Highlights: We developed a new UHPLC-MS/MS method with high sensitivity and selectivity for the quantification of five DL-amino acids in beer. The analysis of five DL-amino acids in beer by LC-MS is the first report. The method can be used to determine the content of DL-amino acid in beer from different manufacturers. [ABSTRACT FROM AUTHOR]

Abstract: Soil has been regarded as a rich source of antibiotic resistance genes (ARGs) due to the complex microbial community and diverse antibiotic-producing microbes in soil, however, little is known about the ARGs in unculturable bacteria. To investigate the diversity and distribution of ARGs in soil and assess the impact of agricultural practice on the ARGs, we screened soil metagenomic library constructed using DNA from four different agricultural soil for ARGs. We identified 45 clones conferring resistance to minocycline, tetracycline, streptomycin, gentamicin, kanamycin, amikacin, chloramphenicol and rifampicin. The similarity of identified ARGs with the closest protein in GenBank ranged from 26% to 92%, with more than 60% of identified ARGs had low similarity less than 60% at amino acid level. The identified ARGs include aminoglycoside acetyltransferase, aminoglycoside 6-adenyltransferase, ADP-ribosyl transferase, ribosome protection protein, transporters and other antibiotic resistant determinants. The identified ARGs from the soil with manure application account for approximately 70% of the total ARGs in this study, implying that manure amendment may increase the diversity of antibiotic resistance genes in soil bacteria. These results suggest that antibiotic resistance in soil remains unexplored and functional metagenomic approach is powerful in discovering novel ARGs and resistant mechanisms. [Copyright &y& Elsevier]

The ventilation filters from ventilation system in the control area of nuclear power plant will be regularly replaced. In general, the metal frame of the waste filters would not be activated and were expected with a low radiation level, thereby it could be recycled or reused after a systematic clearance assessment. As a regulatory requirement in China, this kind of assessment play a vital role in the radioactive waste management, and a detailed scheme should be established based on long-terms of experience and the unit-specific characteristics. Focus on this, a clearance assessment scheme for the metal frames in nuclear power plants was established in this paper, which would present experience in the radioactive waste management for the nuclear power plant operator and the authorities. [ABSTRACT FROM AUTHOR]

• We have developed a novel chiral mass spectrometry derivatization reagent, NCS-OTPP, for the enantiomeric separation of chiral thiol compounds by UHPLC-Q-Orbitrap HRMS. • A high sensitive, high selective and high accurate method was established for the detection and separation chiral thiol compounds. • Three kinds of free and total chiral thiol compounds in serum of human were detected and D-Hcy was determined in human serum for the first time. • The differences of three kinds of free and total chiral thiol compounds in serum from human at normal and stress states were compared. Measurement of chiral thiol compounds such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) in human serum plays an important role in the early diagnosis and warning of cardiovascular disease, neurodegenerative disease, and cancer. We developed a novel chiral mass spectrometry derivatization reagent, (R)-(5-(3-isothiocyanatopyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium (NCS-OTPP), with triphenylphosphine (TPP) as a basic structure carrying a permanent positive charge for the diastereomeric separation of chiral thiol compounds by ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). A novel method was developed for simultaneous determination of three kinds of chiral thiol compounds based on the NCS-OTPP derivatization method. Three kinds of chiral thiol compounds on a YMC Triart C18 (2.0 × 150 mm, 1.9 μm) column with Rs were 1.56–1.68. The protonated precursor to product ion transitions monitored for GSH was m/z 780.16→747.24/473.18, Cys was m/z 594.20→561.18/473.18, and Hcy was m/z 608.21→575.19/473.18. An excellent linearity for all the analytes with correlation coefficients ≥ 0.9995 and suitable precision with inter-day and intra-day coefficients of variation RSDs was 0.83–4.06% and 0.95–3.11%. Satisfactory accuracy with recoveries between 83.73 and 103.35% was observed. The limit of detection (S/N = 3) was 2.4–7.2 fmol. Furthermore, the method was successfully applied to the simultaneous determination of three kinds of free and total thiol compounds in serum from 10 healthy volunteers at normal and stress states. [ABSTRACT FROM AUTHOR]

• Dried saliva spot (DSS) of uric acid (UA) was proposed as a sampling technique. • The determination of UA in saliva using DSS sampling method is the first example. • Content of UA in saliva and serum from 61 volunteers showed a positive correlation. Concentration of uric acid (UA) in serum is one of the markers used to diagnose gout and hyperuricemia. However, serum treatment and storage are cumbersome, and wounds are susceptible to infection. Therefore, a new sampling and analysis method using noninvasive biological samples has been developed, called the dried spot method of UA in human saliva (DSM-UHS). Saliva (5 μL) was dropped on filter paper (a spot with a diameter of 5 mm) containing hypoxanthine (IS) (5 μL) and dried at room temperature for 30 min. The filter paper was immersed in 200 μL of lithium carbonate solution and shaken in a block bath shaker for 5 min at 30 °C. Afterward, the extraction was concentrated and reconstituted with 100 μL of lithium carbonate solution analyzed by HPLC-UV. When comparing the concentration of UA in the human saliva of hyperuricemia patients (HPs) and with that of healthy volunteers (HVs), we observed the concentration of UA was higher in the HPs than in the HVs (p < 0.0001). In addition, the results showed a significant linear relationship between the content of UA in saliva and the content of UA in the serum (r = 0.6243). The content of UA in human saliva could indirectly reflect the content of UA in human serum. Then DSM-UHS could be used to determine the content of UA in the saliva of HVs and HPs. This study provides a new research method and strategy for the determination of human UA content and the clinical prewiring of hyperuricemia. [ABSTRACT FROM AUTHOR]

The protozoan parasite Giardia duodenalis is known to infect humans and a wide range of animals globally. However, no studies on G. duodenalis infection in Bactrian camels have been reported. In the present study, in order to examine the prevalence and genetic diversity of G. duodenalis in Bactrian camels, 852 fecal samples were collected from 24 sampling sites in three geographical areas (Gansu province, Inner Mongolia, and Xinjiang Uygur autonomous regions) of northwestern China, and subjected to multilocus sequence typing (MLST) analysis targeting the 18S rRNA, β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. About 84 fecal samples tested positive for Giardia infection, with an overall prevalence of 9.8%, including three samples from camel calves with diarrhea. Significant differences (χ2 = 80.7, df = 2, P < 0.01) in the prevalence were found in Bactrian camels belonging to three geographical areas, with the highest (33.3%) in Gansu province and the lowest (4.2%) in Xinjiang Uygur autonomous region. Furthermore, significantly different prevalences (χ2 = 34.2, df = 2, P < 0.01) were revealed among age groups, with the highest (35.7%) in camels aged 3 to 6 years old, and the lowest (7.5%) in camels aged > 6 years old. Sequence analysis identified two assemblages, including zoonotic assemblage A and ungulate-adapted assemblage E, with the latter as the dominant G. duodenalis assemblage in each age group and at all sampling sites having positive samples except Hotan. Genetic variations were detected among G. duodenalis isolates in these camels, and eight, three, and seven haplotypes were identified at loci bg, gdh, and tpi, respectively, forming two multilocus genotypes (MLGs) of zoonotic assemblage A and one MLG of assemblage E. To the best of our knowledge, this is the first report on G. duodenalis infection in Bactrian camels, and the data indicate that G. duodenalis have a broad host range. [ABSTRACT FROM AUTHOR]

A novel derivatization reagent, N -[1-Oxo-5-(triphenylphosphonium)pentyl]-( S )-3-aminopyrrolidine (OTPA), with triphenylphosphine (TPP) as a basic structure carrying a permanent positive charge was developed for the enantiomeric separation of chiral carboxylic acids by high-performance liquid chromatography (HPLC). OTPA reacted with the carboxylic acids at 40 °C within 90 min in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and 1-hydroxybenzotriazole (HOBt). The degree of epimerization (racemization) during the derivatization reaction was negligible. The separability of the diastereomers was evaluated in terms of their resolution value (Rs). The Rs values of the derivatives of non-steroidal anti-inflammatory drugs (NSAIDs), which were selected as the representative carboxylic acids, were completely separated by reversed-phase chromatography using an ODS (4.6 mm × 150 mm I.D., 5.0 μm) column. The resolution Rs values were 1.54–2.23 for the evaluated carboxylic acids and the OTPA-derivatization was also effective for the enantiomeric separation of chiral carboxylic acids. The calibration curves (r 2 > 0.9971) were linear over the concentration range of 0.0125–1.25 mM for each enantiomer of ketoprofen (KET), and naproxen (NAP), 0.05–1.0 mM for each enantiomer of ibuprofen (IBU), 2-phenylpropionic acid (PPA), and loxoprofen (LOX), and 0.05–1.25 mM for each enantiomer of PBA. The limit of detection (S/N = 3) for each of the enantiomers of the NSAIDs and chiral carboxylic acid enantiomers was 1.4–7.6 μmol/L. The inter-day and intra-day assay precisions were all < 6.77% and the mean recoveries (%) of the NSAIDs and chiral carboxylic acids from the spiked human plasma were 95.27–101.12%. The derivatization followed by HPLC-UV enabled the separation and detection of NAP in human plasma with simple pretreatment. [ABSTRACT FROM AUTHOR]

New Findings What is the central question of this study? We investigated whether the LPL gene rs283 polymorphism affects exercise-induced changes in body composition and lipid and glucose metabolism in obese adolescents and whether it is functional., What is the main finding and its importance? Chinese obese adolescents of Han nationality with the GG genotype of the rs283 polymorphism were more sensitive to exercise-induced reduction of the body fat percentage, insulin resistance and plasma triglyceride levels. The G allele can significantly increase reporter gene expression level, which may be the molecular reason for the difference in exercise-induced parameter changes among obese adolescents., The aim of this investigation was to explore the association between the rs283 polymorphism located in the lipoprotein lipase ( LPL) gene and exercise-induced changes in body composition and lipid and glucose metabolism in obese adolescents and to probe into the molecular regulatory mechanisms. Fifty-five obese adolescents of Han nationality underwent aerobic training for 4 weeks. Body composition and lipid and glucose metabolic parameters were tested before and after the training. The rs283 polymorphism was genotyped by PCR-restriction fragment length polymorphism, and association analysis with the weight-reducing effect was performed. The regulatory mechanisms of the rs283 polymorphism were explored through the dual-luciferase reporter assay. Exercise-induced change rates were as follows: the change in body fat percentage of GG genotype groups was 3.37 ± 1.60, significantly higher than that of GA genotype groups (2.09 ± 1.53, P < 0.01); the change in the homeostasis model assessment of insulin resistance was 0.52 ± 0.13, obviously higher than that of GA genotype groups (0.44 ± 0.10, P < 0.05); and the change in triglyceride was 51.91 ± 6.56, much higher than that of GA genotype groups (47.06 ± 5.36, P < 0.01). The relative luciferase activity of the reporter gene in recombinant vector carrying the G allele was 2.67 ± 0.22, markedly higher than that in recombinant vector carrying the A allele (1.63 ± 0.03, P < 0.01). Chinese obese adolescents of Han nationality with GG genotype of the rs283 polymorphism were more sensitive to exercise-induced parameter changes. The G allele can improve reporter gene expression level, indicating the effects of rs283 on gene expression. [ABSTRACT FROM AUTHOR]

The researches in the dynamic changes of the progress of HSCs aging are very limited and necessary. In this study, male C57BL/6 mice were divided into 5 groups by age. We found that the superoxide damage of HSPCs started to increase from the middle age (6 months old), with notably reduced antioxidation ability. In accordance with that, the senescence of HSPCs also started from the middle age, since the self-renewal and differentiation ability remarkably decreased, and senescence-associated markers SA-β-GAL increased in the 6-month-old and the older groups. Interestingly, the telomere length and telomerase activity increased to a certain degree in the 6-month-old group. It suggested an intrinsic spontaneous ability of HSPCs against aging. It may provide a theoretical and experimental foundation for better understanding the senescence progress of HSPCs. And the dynamic biological characteristics of HSPCs senescence may also contribute to the clinical optimal time for antiaging drug intervention. [ABSTRACT FROM AUTHOR]

Highlights: [•] Template P123 was effectively removed by ultrasonic extraction from MA. [•] MA treated by ultrasonic extraction shows excellent structural performance. [•] The recovered P123 have been reused as the template in the synthesis procedure of MA. [ABSTRACT FROM AUTHOR]

We have investigated oxidized low-density lipoprotein (ox-LDL) induced senescence in hematopoietic stem cells (HCs). Mouse Sca-1+ HCs were separated and purified using the magnetic activated cell sorting technique. Ox-LDL induced significant senescence in HCs measured by SA-β-Gal staining, and reduced CFU-Mix colony-forming capacity, arresting cells at G0/G1 phase. In agreement with the cell cycle arrest, ox-LDL markedly reduced the expression of CDK4, cyclin D, and cyclin E. As possible contributing factors for cell senescence, ox-LDL also induced cellular oxidative stress and reduced telomerase activity. [ABSTRACT FROM AUTHOR]

Abstract: In combination with abasic site (AP site)-containing DNAs, potential use of a biotic fluorescence compound, Vitamin B2 (riboflavin), is demonstrated for the fluorescence detection of the thymine (T)-related single-nucleotide polymorphisms. Our method is based on construction of the AP site in DNA duplexes, which allows small ligands to bind to target nucleotides accompanied by fluorescence signaling: an AP site-containing probe DNA is hybridized with a target DNA so as to place the AP site toward a target nucleobase, by which hydrophobic microenvironments are provided for ligands to recognize target nucleotides through stacking and hydrogen-bonding interactions. In 10mM sodium cacodylate buffer solutions (pH 7.0) containing 100mM NaCl and 1.0mM EDTA, Vitamin B2 is found to selectively bind to T (K 11 =1.8×106 M−1 at 5°C) over other nucleobases, and this is accompanied by significant quenching of its fluorescence. While the sensing functions depend on the flanking sequences to the AP site, Vitamin B2 is applicable to the detection of T/C (cytosine), T/G (guanine) and T/A (adenine) mutation sequences of the CYP2A6 gene, where the flanking nucleobases are guanines in both positions (–GXG–, X =AP site). [Copyright &y& Elsevier]

In combination with abasic site (AP site)-containing oligodeoxynucleotides (ODNs), we demonstrate potential use of a hydrogen bond forming ligand, 2-amino-7-methyl-1,8-naphthyridine (AMND), for the fluorescence detection of the cytosine (C)/guanine (G) mutation sequence of the cancer repression gene p53. Our method is based on construction of the AP site in ODN duplexes, which allows small synthetic ligands to bind to target nucleobases accompanied by fluorescence signaling: an AP site-containing ODN is hybridized with a target ODN so as to place the AP site toward a target nucleobase, by which hydrophobic microenvironments are provided for ligands to recognize target nucleobases through hydrogen-bonding. In 10 mM sodium cacodylate buffer solutions (pH, 7.0) containing 100 mM NaCl and 1.0 mM EDTA, AMND is found to strongly bind to C (Kd=1.5×10−6 M) in the target ODN while the binding affinity for G is relatively moderate (Kd=50×10−6 M). Significant fluorescence quenching of AMND is observed only when binding to C, making it possible to judge the C/G transversion with the naked eye. [Copyright &y& Elsevier]

• A highly sensitive UHPLC-HRMS method was provided for the simultaneous analysis of GSH, DL-Cys and DL-Hcy. • D-Hcy was determined in human urine for the first time. • Fitted curves for ratios of D/L-Cys and D/L-Hcy were a convenient and effective method to evaluate oxidative stress. A high-sensitivity and -selectivity mass spectrometry derivatization reagent, (R)-(5-(3-isothiocyanatopyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium (NCS-OTPP), was developed for the enantiomeric separation of chiral thiol compounds as prospectively important diagnostic markers for oxidative stress-related diseases. Complete separation of GSH, DL-Cys, and DL-Hcy was achieved. The parent ions of all derivatives had a fragment of m/z 473.18 and a structure of m/z 75.95 (R-S = C-S-R'), conducive to qualitative and quantitative analysis. Good linear relationships were obtained for all analytes (R2 ≥ 0.9995). The intra-day and inter-day precision were 0.82–5.16 % and 1.02–4.18 % in saliva, and 0.81–3.45 % and 0.99–6.47 % in urine, with mean recoveries of 83.31–105.66 % and 84.09–101.11 %, respectively. The limit of detection (S/N = 3) was 19.20–57.60 nM. Free and total GSH, DL-Cys, and DL-Hcy were detected simultaneously in saliva and urine from 10 volunteers in the normal, stressed, and stable states by UHPLC-Q-Orbitrap HRMS. The thiol compounds were quantitatively related to oxidative stress state changes. [ABSTRACT FROM AUTHOR]