Simultaneous Determination of Chiral Thiol Compounds and Monitoring of Dynamic Changes in Human Urine after Drinking Chinese Korean Ethnic Rice Wine

Relative quantitation of chiral thiol compounds labeled based on isotope novel mass spectrometry probes: Monitoring of the dynamic changes of chiral thiol compounds in human urine during normal, exercise, and rest recovery states

Monitoring changes in the content of chiral thiol compounds in the human body is crucial for the early diagnosis of oxidative stress-related diseases and the exploration of their pathogenesis. To address this, we synthesized a novel isotope mass spectrometry (MS) probe, denoted as (R)-(5-(3-isothiocyanato (13C) pyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium (N13CS-OTPP), with triphenylphosphine as its parent structure. In this study, we established a new ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLCHRMS) relative quantitative method to monitor chiral thiol compounds in human urine under varying oxidative stress conditions. This method relies on the ratio of 12C/13C isotope-labeled peak areas. To assess the chiral separation efficiency of N13CS-OTPP, we employed three types of thiol compounds (D/L-GSH, D/L-Cys, and D/L-Hcy) and observed separation degrees (Rs) ranging from 1.82 to 1.89. We further validated the accuracy and feasibility of our relative quantitative methods using D/L-Cys-as a model compound. N12C/13CS-OTPP-Cys-exhibited excellent linearity (R2 = 0.9993-0.9994) across different molar ratios (D/L-Cys = 10:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:10) and achieved a low limit of detection (LOD) of 2.5 fmol. Additionally, we monitored the dynamic changes in urine D/L-Cys-and D/L-Hcy ratios in 12 healthy volunteers (six males and six females) under various oxidative stress states. We generated fitting curves and investigated the trends in chiral thiol compounds in vivo. This study introduces a novel method for the relative quantitative monitoring of chiral thiol compounds in different oxidative stress states within the human body. It also presents a new strategy for understanding the pathogenesis of related diseases resulting from the abnormal metabolism of thiol compounds.

Development of a diphenyl sulfide structure derivatization reagent for amino acid enantiomers analysis: Application of dynamic monitoring in human urine after drinking wine

We developed a novel chiral mass spectrometry derivatization reagent (S)-(3-(4-carboxythiazolidin-3-yl)-3-oxopropyl) diphenylsulfonium (CTOD) with a positively charged sulfur-containing structure for high-sensitivity detection of the chiral resolution of amino acid enantiomers. CTOD reacted with DL-amino acids at 60^oC for 60 min to generate the corresponding diastereomers, fifteen chiral amino acid-derived products were separated. Resolution (Rs) values were of the range 1.54-4.36, except Asn 1.07, achieving good separation. A highly sensitive and selective UHPLC-MS/MS method for the simultaneous determination and chiral separation of five chiral amino acids (Pro, Ala, Glu, Asp, and Phe) based on CTOD derivatization was established and applied to the detection of chiral amino acids in different wines. The diastereomeric resolution of the five amino acids was 1.71-5.42, and an excellent linear relationship was obtained in the range of 0.25-500 pmol (R² ≥0.9993). The detection limit was 0.05-0.25 pmol. The intra- and inter-day precisions were 0.51-5.76% and 0.78-5.18%, respectively, and the average recovery was 90.03-99.99%. In addition, the metabolic concentration of chiral amino acids was monitored after drinking red wine and white wine, and the fitting curve of metabolic concentration was drawn.

A novel UHPLC-MS/MS method for the determination of four α-dicarbonyl compounds in wine and dynamic monitoring in human urine after drinking

α-dicarbonyl compounds (α-DCs) serve as potential biomarkers for oxidative stress-related diseases but are difficult to detect.To study the metabolism of carbonyl compounds, we developed a new mass spectrometry probe, 3-benzyl-2-oxo-4λ³-thiazolidine-4-carbohydrazide (BOTC), containing hydrazyl groups for the targeted detection of carbonyl functional groups.In a novel approach, we used BOTC pre-column derivatization with ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to simultaneously detect four kinds of α-DCs in red wine as well as in urine after drinking. The α-DCs were completely separated (R² ≥ 0.9995), detection was sensitive (detection limit was 12.5-50 fmol), consistent (intraday and interday precision was 0.1-5.7 %), and efficient (average recoveries were 103.3-110.2 %). The method was applied to the analysis of α-DCs in different wines and the dynamic monitoring of transit and excretion in vivo after drinking. Our novel method provides a new strategy for the detection of α-dicarbonyl compounds in red wine and dicarbonyl compounds produced in oxidative stress-related diseases.

Highly sensitive novel fluorescent chiral probe possessing (S)-2-methylproline structures for the determination of chiral amino compounds by ultra-performance liquid chromatography with fluorescence: An application in the saliva of healthy volunteer

We developed a novel fluorescent chiral probe, DBD-trans-2-methyl-L-proline (DBD-M-Pro), which can be used to target recognition of amino functional groups using chiral resolution. To investigate the chiral resolution efficiency, 20 chiral amino enantiomers (19 DL-amino acids and phenylethylamine) were labeled using ultra-performance liquid chromatography (UPLC) with a fluorescence (FL) system. Diastereomers were formed by the reactions of DBD-M-Pro with enantiomers of amino functional groups at 60 °C for 60 min and detected on a BEH C18 column (100 × 2.1 mm, 1.7 μm). Gradient elution of 10 mM ammonium acetate with 0.05% formic acid (FA) aqueous solution and 0.1% FA acetonitrile or 0.1% FA methanol solution was performed at an excitation wavelength (Ex) 460 nm and emission wavelength (Em) 550 nm. Each resulting derivative of D- and L- type was effectively separated. The results showed that the resolution (Rs) of 17 amino acids and phenylethylamine (PEA) in the range of 1.59-24.11, except for histidine (His) (Rs = 1.32) and serine (Ser) (Rs = 1.47), achieved completely separation. The DBD-M-Pro chiral probe has a robust chiral selectivity for D-amino acids. Furthermore, a new method for the simultaneous determination of six DL-amino acids (Pro, Val, Trp, Phe, Leu, Lys) in human saliva was developed. The proposed method showed resolution values of 1.78-16.38, and an excellent linear relationship was obtained in the range of 2.5-500 pmol (R² ≥ 0.9990). The limit of detection (S/N = 3) ranged from 0.5 to 3.75 pmol. The intra-day and inter-day coefficient of variation (CV) were within the range of 1.75-11.73%. The average addition recoveries in saliva ranged from 95.99 to 106.97%. The methodology was used to determine the content of DL-amino acids and the D/L-amino acid ratio in the saliva of 40 healthy volunteers (15 males and 25 females), as well as evaluating the differences between men and women. Our study suggests that the DBD-M-Pro chiral probe could be an effective tool for screening potential D-amino acid biomarkers in disease.