Metabolomic characterization of semen from asthenozoospermic patients using ultra-high-performance liquid chromatography–tandem quadrupole time-of-flight mass spectrometry

Asthenozoospermia (AS) is a common factor of male infertility, and its pathogenesis remains unclear. The purpose of this study was to investigate the differential seminal plasma metabolic pattern in asthenozoospermic men and to identify potential biomarkers in relation to spermatogenic dysfunction using sensitive ultra-high-performance liquid chromatography–tandem quadruple time-of-flight MS (UHPLC–Q-TOF/MS). The samples of seminal plasma from patients with AS (n = 20) and healthy controls (n = 20) were checked and differentiated by UHPLC–Q-TOF/MS. Compared with the control group, the AS group showed a total of nine significantly different metabolites, including increases in creatinine, uric acid, N⁶-methyladenosine (m⁶A), uridine, and taurine and decreases in carnitine, nicotinamide, N-acetylputrescine and l -palmitoylcarnitine. By analyzing the correlation among these metabolites and clinical computer-assisted semen analysis reports, we found that m⁶A is significantly correlated with not only the four decreased metabolites but also with sperm count, motility, and curvilinear velocity. Furthermore, nicotinamide was shown to correlate with other identified metabolites, indicating its important role in the metabolic pathway of AS. Current results implied that sensitive untargeted seminal plasma metabolomics could identify distinct metabolic patterns of AS and would help clinicians by offering novel cues for discovering the pathogenesis of male infertility.     

High-throughput intracellular pteridinic profiling by liquid chromatography–quadrupole time-of-flight mass spectrometry

Pteridines are a diverse family of endogenous metabolites that may serve as useful diagnostic biomarkers for disease. While many preparative and analytical techniques have been described for analysis of selected pteridines in biological fluids, broad intracellular pteridine detection remains a significant analytical challenge. In this study, a novel, specific and sensitive extraction and high performance liquid chromatography–quadrupole time-of-flight mass spectrometry (HPLC–QTOF MS) method was developed to simultaneously quantify seven intracellular pteridines and monitor 18 additional, naturally-occurring intracellular pteridines. The newly developed method was validated through evaluation of spiked recoveries (84.5–109.4%), reproducibility (2.1–5.4% RSD), method detection limits (0.1–3.0 μg L⁻¹) and limits of quantitation (0.1–1 μg L⁻¹), and finally application to non-small cell lung cancer A549 cells. Twenty-three pteridine derivatives were successfully detected from cell lysates with an average RSD of 12% among culture replicates. Quantified intracellular pteridine levels ranged from 1 to 1000 nM in good agreement with previous studies. Finally, this technique may be applied to cellular studies to generate new biological hypotheses concerning pteridine physiological and pathological functions as well as to discovery new pteridine-based biomarkers.     

Separation and identification of terpene-conjugated curcuminoids based on liquid chromatography–tandem mass spectrometry and their in vitro anti-inflammatory activities

Terpene-conjugated curcuminoids are conjugates of curcuminoids and bisabolanes in the rhizomes of Curcuma longa L. The fragmentation pathways of known three terpene-conjugated curcuminoids (bisabolocurcumin-ether, bisabocurcumin, and demethoxybisabolocurcumin ether) and curcumin, demethoxycurcumin, and bisdemethoxycurcumin were investigated using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode to rapidly search and discover similar unknown compounds of the acetone fraction of turmeric. Subsequently, compounds 1–3 were founded in the acetone fraction based on molecular weight and above fragmentation pathways (the characteristic fragment ions, the most and second most abundant fragment ions produced in MS² spectra). Terpecurcumin X ( 1 ) and terpecurcumin Y ( 3 ) were further separated by liquid chromatography–tandem mass spectrometry guided isolation technique to verify their structures by nuclear magnetic resonance, electrospray ionization high-resolution mass spectroscopy, ultraviolet and visible spectra and infrared spectra. Interestingly, 1 and 3 were new compounds. The results indicate the feasibility and significant advantages of liquid chromatography–tandem mass spectrometry for the rapid discovery and analysis of new constituents in traditional Chinese medicine. In vitro, Terpene-conjugated curcuminoids had better nitric oxide inhibitory activity than the other seven curcuminoids (demethoxycurcumin, bisdemethoxycurcumin, curdione, curcumenone, bisacurone, curcumenol, and germacron).     

Rapid separation and characterization of comprehensive ingredients in Yangxinshi tablet and rat plasma by ultrahigh-performance liquid chromatography–quadrupole time-of-flight mass spectrometry

Ultrahigh-performance liquid chromatography–quadrupole-time of-flight mass spectrometry (UHPLC–Q-TOF-MS) was widely used in identification of complex ingredients in traditional Chinese herbs and herbal medicinal preparations for its excellent performance. Yangxinshi tablet, a Chinese compound herbal medicinal formula, has excellent efficacy for the clinical treatment of cardiovascular diseases, but its active ingredients are unclear. In this study, a rapid and sensitive UHPLC–Q-TOF/MS and secondary mass spectrometry (MS²) method were developed to characterize the comprehensive ingredients in Yangxinshi tablet and rat plasma after drug administration. And finally a total of 178 constituents in the Yangxinshi tablet were identified effectively, and 39 parent molecules in rat plasma were rapidly characterized by matching the Yangxinshi tablet chemical library established by ourselves. Of which, seven groups of isomers were further distinguished according to their MS² spectra and fragmentation ions. Furthermore, 31 metabolites in the rat plasma were specified and elucidated according to their typical fragmentation ions, and their main metabolic pathways were hydration of phase I reaction and glucuronidation of phase II reaction. It is concluded that this established analysis method is rapid, specific, and practical, and these analysis results will provide help for further quality control and pharmacological study of Yangxinshi tablet.     

Rapid profiling of cantharidin analogs in Mylabris phalerata Pallas by ultra-performance liquid chromatography–quadrupole time-of-flight–tandem mass spectrometry

We evaluated the protective effect and toxicity of extracts from Mylabris phalerata Pallas by measuring the activated partial thromboplastin time, prothrombin time, venous thrombosis and acute toxicity in rats. Results showed the petroleum ether and water fractions of M. phalerata inhibited thrombosis but hardly prolonged the activated partial thromboplastin time and prothrombin time in rats. The trichloromethane fraction had obvious toxicity with an LD₅₀ of 0.2 g/kg in vivo, and contained many cantharidin analogs (CAs) by ultra-performance liquid chromatography–quadrupole ion trap–tandem mass spectrometry (UPLC–QTRAP–MS/MS). CAs are the major potential bioactivity constituent in M. phalerata. An effective and reliable UPLC–QTRAP–MS/MS method was successfully developed to separate and identify CAs. The fragmentation patterns of five purified compounds were applied to elucidate the structure of their analogs. Thirty-four CAs were characterized or tentatively identified, eight of which are proposed to be novel compounds ( 13 – 17 , 20 , 21 , 23 ), and their fragmentation patterns were investigated for the first time. Most importantly, a rapid and reliable UPLC–MS method was developed to identify the CAs of M. phalerata. This method has contributed to the discovery of most of these unknown analogs or their metabolites in M. phalerata effectively and quickly, and does not rely on limited chemical structural diversity libraries.     

Determination of ecgonine and seven other cocaine metabolites in human urine and whole blood by ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry

Ecgonine is suggested to be a promising marker of cocaine (COC) ingestion. A combined mass spectrometry (MS) and tandem MS (MS/MS) method was developed to simultaneously determine ecgonine and seven other metabolites of cocaine in human urine and whole blood with ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The compounds were extracted from as little as 100 μL of sample by solid-phase extraction with a 96-well μElution solid-phase extraction plate. The protonated molecules or fragment ions at accurate mass acquired in MS mode were used to quantify specific analytes, following by dedicated MS/MS identification. The assay was linear in the range from 5 to 50-100 ng/mL for urine samples, except for ecgonine methyl ester (10-200 ng/mL) and ecgonine (40-400 ng/mL), and was linear from 1-2 to 50 ng/mL for whole blood samples, except for ecgonine methyl ester (20-1,000 ng/mL) and ecgonine (40-2,000 ng/mL). The correlation coefficients were all greater than 0.99. The limits of detection ranged from 0.2 to 16 ng/mL, and the lower limits of quantification ranged from 1 to 40 ng/mL. The repeatability and intermediate precision were 18.1 % or less. The accuracy was in the range from 80.0 to 122.9 %, process efficiencies were in the range from 8.6 to 177.4 %, matrix effects were in the range from 28.7 to 171.0 %, and extraction recoveries were in the range from 41.0 to 114.3 %, except for ecgonine (12.8 % and 9.3 % at low and high concentrations, respectively). This method was highly sensitive in comparison with previously published methods. The validated method was successfully applied to the analysis of real samples derived from forensic cases, and the results verified that, on the basis of data from four positive samples, ecgonine is a promising marker of cocaine ingestion.

Nano-Cuo–Au-catalyzed solvent-free synthesis of α-aminophosphonates and evaluation of their antioxidant and α-glucosidase enzyme inhibition activities

A new green and efficient method has been developed for the synthesis of α-aminophosphonates through one-pot three-component Kabachnik–Fields reaction. It involves the reaction of a 2-aminophenol with different substituted aromatic aldehydes and dimethyl phosphite in the presence of nanocopper oxide–gold (CuO–Au) catalyst under solvent-free conditions at 60?°C. Nano-CuO–Au catalyst was found to have many advantages like high activity, simple workup, and good (87%) to very high yields (96%). The products were characterized by IR, ¹H, ¹³C, and ³¹P NMR spectra and elemental analysis. All the synthesized compounds were screened for in vitro antioxidant and α-glucosidase inhibition activities. The compound 4b showed higher 2,2-diphenyl-1-picrylhydrazyl and H₂O₂ radical scavenging activity and compound 4e showed higher NO radical scavenging activity than the standard ascorbic acid. The compound 4j has much higher α-glucosidase enzyme inhibition activity than the standard acarbose.     

A liquid chromatography coupled to quadrupole–time-of-flight–mass spectrometry (LC–QTOF–MS) method for identification analysis of saponins from Quillaja saponaria bark extracts in foot-and-mouth disease vaccines: Development,validation and applicability

Saponins from Quillaja saponaria have been commonly used as immunomodulatory adjuvants in foot-and-mouth disease vaccines (FMDVs). However, due to the lack of consensus over the possible exacerbation of local inflammatory responses in cattle and its economic impacts, their use has been discouraged by Brazilian authorities. A qualitative method intended to determine the presence of saponins from Q. saponaria bark extracts in FMDVs was developed and validated. Instrumental analysis was performed using an liquid chromatography (LC) coupled to a quadrupole–time-of-flight–mass spectrometry (TOF-MS) system. The method was validated according to the International Conference on Harmonization Harmonized Tripartite Guideline Q2 (R1) and Brazilian Ministry of Agriculture, Livestock and Food Supply Analytical Quality Assurance Guidelines. Validation parameters were determined and considered suitable to the established criteria. The validated method has been applied in routine analysis in the National Agricultural Laboratory at Rio Grande do Sul (LANAGRO-RS). All results obtained were in agreement with the vaccine's composition described by the manufacturer. The method is easy and adequate for analysis in routine laboratories. To the best of the authors' knowledge, this is the first report of a method which intends to investigate the presence of saponins from Q. saponaria bark extracts in veterinary vaccines.     

Combination of β-elimination and liquid chromatography/quadrupole time-of-flight mass spectrometry for the determination of O-glycosylation sites

Determination of O-glycosylation sites in glycopeptides was developed by using two model compounds designed from mucin2 tandem repeat motif and erythropoietin. β-Elimination/addition reaction using dimethylamine on glycosylated site through a Michael-type condensation produced efficient deglycosylation with appropriate chemical modification. The use of dimethylamine was efficient to release the O-linked glycan in a reaction time period of 2-6 h at 55 °C. Peptide sequencing was then performed using the liquid chromatography/quadrupole time-of-flight mass spectrometry and MS-MS experiments. Interpretation of fragmentation pathways of the β-elimination/addition products enabled straightforward recognition of glycosylation site. Compared to the fragmentation of corresponding native peptides, mass shift of −18 Da or +27 Da was clearly observed for the two kinds of β-elimination/addition products of the glycosylated threonine. Dimethylamine was found to provide higher efficiency of β-elimination/addition than methylamine and ammonia.     

Fast analysis of doping agents in urine by ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry. II: Confirmatory analysis

For doping control, analyses of samples are generally achieved in two steps: a rapid screening and, in the case of a positive result, a confirmatory analysis. A two-step methodology based on ultra-high-pressure liquid chromatography coupled to a quadrupole time-of-flight mass spectrometry (UHPLC–QTOF-MS) was developed to screen and confirm 103 doping agents from various classes (e.g., β-blockers, stimulants, diuretics, and narcotics). The screening method was presented in a previous article as part I (i.e., Fast analysis of doping agents in urine by ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry. Part I: screening analysis). For the confirmatory method, basic, neutral and acidic compounds were extracted by a dedicated solid-phase extraction (SPE) in a 96-well plate format and detected by MS in the tandem mode to obtain precursor and characteristic product ions. The mass accuracy and the elemental composition of precursor and product ions were used for compound identification. After validation including matrix effect determination, the method was considered reliable to confirm suspect results without ambiguity according to the positivity criteria established by the World Anti-Doping Agency (WADA). Moreover, an isocratic method was developed to separate ephedrine from its isomer pseudoephedrine and cathine from phenylpropanolamine in a single run, what allowed their direct quantification in urine.     

Study on chemical constituents and fingerprints of Phellodendron amurense Rupr. based on ultra-performance liquid chromatography–quadrupole–time-of-flight–mass spectrometry

The chemical constituents from Phellodendron amurense Rupr. were characterized systematically by ultra-performance liquid chromatography—quadrupole–time-of-flight–mass spectrometry method for collecting mass spectrometry data, and the fingerprints method was established, providing reference for its quality control. The chromatographic column was ACQUITY UPLC BEH-C₁₈ (100 mm×2.1 mm, 1.7 μm). The mobile phase was acetonitrile-0.1% formic acid aqueous solution and the compounds from P. amurense Rupr. were identified by Qualitative Analysis 10.0 software, reference substance, retention time, mass spectrometry fragmentation pattern and database retrieval. Meanwhile, liquid chromatography–mass spectrometry fingerprint methods of P. amurense Rupr. and Phellodendron chinense Schneid. were established by using the similarity evaluation system of chromatographic fingerprint of traditional Chinese medicine (2012 edition), and the differences were analyzed by multivariate statistical analysis methods. A total of 105 compounds were identified, including 102 alkaloids, two phenolic acids, and one lactone compound. Liquid chromatography–mass spectrometry fingerprint method was established with ideal precision, stability and repeatability, and 12 quality differential markers were recognized between the above two herbs. Liquid chromatography–mass spectrometry method can be used for qualitative analysis of the constituents of Phellodendron amurense Rupr., providing reference for clarifying the material basis and promoting the clinical precision medication and quality evaluation of P. amurense Rupr.     

Reaction of β-blockers and β-agonist pharmaceuticals with aqueous chlorine. Investigation of kinetics and by-products by liquid chromatography quadrupole time-of-flight mass spectrometry

The degradation of two β-blockers (atenolol and propranolol) and one β-receptor agonist (salbutamol) during water chlorination was investigated by liquid chromatography-mass spectrometry (LC-MS). An accurate-mass quadrupole time-of-flight system (QTOF) was used to follow the time course of the pharmaceuticals and also used in the identification of the by-products. The degradation kinetics of these drugs was investigated at different concentrations of chlorine, bromide and sample pH by means of a Box-Behnken experimental design. Depending on these factors, dissipation half-lives varied in the ranges 68-145 h for atenolol, 1.3-33 min for salbutamol and 42-8362 min for propranolol. Normally, an increase in chlorine dosage and pH resulted in faster degradation of these pharmaceuticals. Moreover, the presence of bromide in water samples also resulted in a faster transformation of atenolol at low chlorine doses. The use of an accurate-mass high-resolution LC-QTOF-MS system permitted the identification of a total of 14 by-products. The transformation pathway of β-blockers/agonists consisted mainly of halogenations, hydroxylations and dealkylations. Also, many of these by-products are stable, depending on the chlorination operational parameters employed.     

Determination of eugenol and isoeugenol in aquaculture water by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometryEI北大核心CSCD

An analytical method was established for the determination of eugenol and isoeugenol in aquaculture water by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry UPLC-Q-TOF-MS. Water samples were derivatized with dansyl chloride. The derivatization products were separated on a ThermoAccucore C18 column100 mm×2.1 mm2.6 μµm under gradient elution condition utilizing acetonitrile and 0.1% formic acid as mobile phases. Q-TOF-MS operating in mass data using alternating collision cell energyMSEmode with positive electrospray ionization was used for the identification of analytes. The results showed that the calibration curves for eugenol and isoeugenol were linear in the range of 0.1-20 μµg/L with the correlation coefficientsrhigher than 0.995. Their recoveries in aquaculture water were 83.2%-102% and 91.8%-104%respectivelywith relative standard deviationsRSDsless than 15%. The limits of detection were 0.02 and 0.05 μµg/L and the limits of quantitation were 0.05 and 0.1 μµg/Lrespectively. The method can be applied to the determination of eugenol and isoeugenol in real water samples. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Determination of pesticides and Pharmaceuticals from Fish Cultivation Water by parallel solid-phase extraction (SPE) and liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QTOF-MS)

A screening method for multiple classes of pesticides and pharmaceuticals from fish cultivation water was established using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Parallel solid-phase extraction (SPE) with different adsorbents was selected for extracting and purifying analytes with different properties. This method allowed for efficient and economical screening of a virtually unlimited number of compounds without reference standards. In order to evaluate the feasibility of this method, 25 pesticides and pharmaceuticals with different properties were selected. The screening detection limit of this method was 0.015?µg L^?1, which was lower than the maximum residue limits. This value showed that the method was suitable for screening organic contaminants in fish cultivation water. In a simulation experiment, the organic contaminants with high intensity (atrazine and carbendazim) were identified by retention time, accurate mass, isotopic pattern, and the main fragment ions. Moreover, the information about the organic contaminants and MS² spectra was added into a database. Since the QTOF-MS data were traceable, they were saved and could be reexamined for compounds that previously were unexpected. This method provides insight into the screening and identification of organic contaminants in water samples, as well as risk assessment and fishery accident identification.     

Systematic characterization of the chemical constituents in vitro and prototypes in vivo of Dingkun Dan using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with the UNIFI™ software

Dingkun Dan (DKD), a famous traditional Chinese medicine, has been widely used in the treatment of irregular menstruation, leucorrhea abnormality, and postpartum gynecological diseases since Qing dynasty (1739). It comprises 30 flavors of Chinese medicinal materials, which results in its complex chemical composition. In this study, an integrative method was developed to rapidly characterize the chemical components of DKD using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with the UNIFI™ software. A total of 234 compounds, including 47 triterpenoid saponins, 55 flavonoids, and 38 alkaloids, were identified. Of them, 170 compounds were characterized initially and 61 compounds were identified unambiguously using reference standards. Under the same analysis conditions, 43 prototypical components, which were tentatively assigned as triterpenoid saponins, flavonoids, alkaloids, terpenoids, phenylpropanoids, and others, were absorbed in rat by serum pharmacochemistry analysis. DKD exhibited diverse pharmacological activities through the combined effect of these components. This study was the first systematic study of chemical components in vitro originating from 30 medicinal materials and prototypes in vivo of DKD, which could provide scientific evidence for explaining its therapeutic effect.     

Serial mixed-mode cation- and anion-exchange solid-phase extraction for separation of basic,neutral and acidic pharmaceuticals in wastewater and analysis by high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry

A novel solid-phase extraction (SPE) method is presented whereby 15 basic, neutral and acidic pharmaceuticals in wastewater were simultaneously extracted and subsequently separated into different fractions. This was achieved using mixed-mode cation- and anion-exchange SPE (Oasis MCX and MAX) in series. Analysis was performed by high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (HPLC/QTOF-MS). A fast separation was achieved, with all compounds eluting within 6 min, narrow chromatographic peaks, with a peak base width of 6 s on average, and a high mass accuracy of quantified wastewater sample ions, with average mass errors in absolute value of 0.7 mDa or 2.7 ppm. The recovery of the SPE method in the analysis of sewage treatment plant (STP) influent and effluent wastewater was on average 80% and the ion suppression 30%. For less demanding samples Oasis MCX used alone may be an alternative method, although for STP influent waters containing high loads of organic compounds the clean-up achieved using only Oasis MCX was insufficient, leading to unreliable quantitation. Furthermore, serial SPE separation according to molecular charge added an additional degree of analyte confirmation. For quantitation, an approach combining external standard calibration curves, isotopically labelled surrogate standards and single-point standard addition was used. The applicability of the method was demonstrated in the analysis of influent and effluent wastewater from an STP, using small sample volumes (25–50 mL). The effluent wastewater had been subjected to three different treatments; activated sludge, activated sludge followed by ozonation, and a membrane bioreactor (MBR). Ozone treatment proved superior in removal of the analysed pharmaceuticals, while the MBR provided higher removal efficiencies than the activated sludge process.     

Identification of protein binders in works of art by high-performance liquid chromatography–diode array detector analysis of their tryptic digests

Proteins in works of art are generally determined by the relative amounts of amino acids. This method, however, implies a loss of information on the protein structure and its modifications. Consequently, we propose a method based on the analysis of trypsin digests using high-performance liquid chromatography (HPLC) UV diode array detection (DAD) for painting binder studies. All reaction steps are done in the same vial; no extraction methods or sample transfer is needed, reducing the risk of sample losses. A collection of pure binders (collagen, ovalbumin, yolk and casein) as well as homemade and historical paint samples have been investigated with this method. Chromatograms of unknowns at 214 nm and 280 nm are compared with those of the reference samples as a fingerprint. There is a good agreement between many peptides, but others seem to have been lost or their retention time shifted due to small compositional changes because of ageing and degradation of the paint. The results are comparable with the results of other techniques used for binder identification on the same samples, with the additional advantage of differentiation between egg yolk and glair.     

Investigation of genetic variants of α-1 acid glycoprotein by ultra-performance liquid chromatography–mass spectrometry

Genetic variants of human plasma alpha-1 acid glycoprotein (AGP) have been studied in cancer, compared with a group of healthy control. AGP has four genetic variants: AGP F1, F2, and S variants correspond to the ORM1 gene whereas AGP A corresponds to the ORM2 gene. The proportion of ORM1 and ORM2 variants were studied in plasma using a novel UPLC–MS method. Plasma total AGP level was 0.5 ± 0.2 g L⁻¹ and the proportions of the ORM1 and ORM2 variants were 76.3 ± 8.2% and 23.7 ± 8.2%, respectively. In cancer plasma AGP levels increased fourfold and the proportion of ORM1 variants increased to 88.7 ± 6.8%. Changes in the proportion of genetic variants due to cancer were clearly significant, as shown by statistical analysis. Three different cancer types have been studied, lymphoma, melanoma, and ovarian cancer. The results did not show any difference depending on cancer type. The results indicate that, in accordance with prior expectations, the ORM1 variant is predominantly responsible for the acute-phase property of AGP.