Liquid Chromatography-mass Spectrometry Studies Research Articles

Liquid Chromatography–Mass Spectrometry Study Focusing on Neuroprotective Effect of Compounds Obtained from Bacopa monnieri Juice

Liquid Chromatography–Mass Spectrometry Study Focusing on Neuroprotective Effect of Compounds Obtained from Bacopa monnieri Juice

High-Performance Liquid Chromatography–Mass Spectrometry Study of the Effect of Accelerated Electrons on the Structure of Bovine Serum Albumin

High-Performance Liquid Chromatography–Mass Spectrometry Study of the Effect of Accelerated Electrons on the Structure of Bovine Serum Albumin

Detections of Chemicals and Migratory Plastics in Peritoneal Dialysis Fluids

Background: Peritoneal dialysis (PD) is an important modality of renal replacement therapy (RRT). Peritonitis and ultrafiltration failure are complications that have a long-term impact on PD patients. Besides touch contamination, procedural errors and clinical reasons of peritonitis, contaminants, and constituents of peritoneal dialysis fluids (PDFs) have been implicated in causing peritonitis and ultrafiltration failure. This study was aimed to test the PDFs in India for the presence of migratory plastics. Materials and Methods: PDFs from the two manufacturers in India were tested using liquid chromatography mass spectrometry (LCMS) and gas chromatography mass spectrometry (GCMS) with headspace analysis (volatile compounds) and pyrolysis of plastics (polymer compounds). The storage conditions and handling were uniform. Results: The results revealed impurities of acetate compounds and aldehyde derivatives of glucose degradation products (GDPs) with contaminants and leachable plastics. There were high levels of GDP derivative in the form of 5-hydroxymethylfurfural compounds (5-HMF). The analysis revealed the presence of plastic softeners in very high concentrations. Conclusion: The study unmasks the presence of chemicals and GDPs that can be implicated in pathogenesis of sterile peritonitis and ultrafiltration failure. The study demonstrated the presence of leachable plastics. In conclusion, LCMS and GCMS studies can be used to test PDFs for unwanted chemicals prior to human use.

DeepRTAlign: toward accurate retention time alignment for large cohort mass spectrometry data analysis

Retention time (RT) alignment is a crucial step in liquid chromatography-mass spectrometry (LC-MS)-based proteomic and metabolomic experiments, especially for large cohort studies. The most popular alignment tools are based on warping function method and direct matching method. However, existing tools can hardly handle monotonic and non-monotonic RT shifts simultaneously. Here, we develop a deep learning-based RT alignment tool, DeepRTAlign, for large cohort LC-MS data analysis. DeepRTAlign has been demonstrated to have improved performances by benchmarking it against current state-of-the-art approaches on multiple real-world and simulated proteomic and metabolomic datasets. The results also show that DeepRTAlign can improve identification sensitivity without compromising quantitative accuracy. Furthermore, using the MS features aligned by DeepRTAlign, we trained and validated a robust classifier to predict the early recurrence of hepatocellular carcinoma. DeepRTAlign provides an advanced solution to RT alignment in large cohort LC-MS studies, which is currently a major bottleneck in proteomics and metabolomics research.

Novel Pyrazinoindolones As Amyloid‐Beta Aggregation Inhibitors

AbstractBackgroundAlzheimer’s disease (AD) is a devastating neurodegenerative condition which primarily affects the elderly population. One of hallmarks of AD is the accumulation of protein aggregates known as amyloid‐beta (Aβ) that promotes neurotoxicity and cognitive decline. Recent discoveries in the field led to the accelerated market approval of anti‐Aβ antibodies aducanumab and lecanemab. These are exciting discoveries. However, considering the cost and patient compliance issues with these biological therapies, discovering novel anti‐Aβ therapies that are based on small molecules is highly desirable due to several advantages over biological therapies including the ease of oral administration, reduced cost involved in bulk manufacturing and better stability on storage.MethodA library of novel pyrazino[1,2‐a]indole‐1(2H)‐one derivatives were designed using the computational modeling software Discovery Studio Structure‐Based‐Design (Biovia Inc, San Diego USA). Then synthetic chemistry protocols were optimized to prepare small molecule library and were characterized by 1H and 13C NMR and Liquid Chromatography Mass Spectrometry studies. The anti‐Aβ activity of these novel molecules toward Aβ40 aggregation was evaluated by fluorescence spectroscopy using the thioflavin‐T based aggregation kinetic studies. In addition, the online web tool SwissADME was used to calculate the physicochemical properties of pyrazino[1,2‐a]indole‐1(2H)‐one derivatives to assess their drug‐likeness, blood‐brain barrier permeability and pharmacokinetics.ResultA novel library of pyrazino[1,2‐a]indole‐1(2H)‐one derivatives were prepared by optimizing a four step or two step synthesis protocol starting from either phenylhydrazine or indole‐2‐carboxylic acid to afford pyrazino[1,2‐a]indole‐1(2H)‐one derivatives 5a–f. In the Aβ40 (5 μM) aggregation kinetics assay, they exhibited 14‐59% inhibition when tested at a range of concentrations (1, 5, 10 and 25 μM), demonstrating their anti‐Aβ properties. Their physicochemical properties suggest their drug‐likeness.ConclusionStructure‐activity relationship studies demonstrate that the fused tricyclic pyrazino[1,2‐a]indole‐1(2H)‐one is a suitable template to i) develop novel chemical tools to study and understand the mechanisms of Aβ40 aggregation and ii) discover novel small molecules as potential therapies for AD.

Microbially catalyzed anode and cathode microbial electrosynthesis system for efficient metformin removal and volatile fatty acid production

The removal of different pharmaceuticals and personal care products from surface water is crucial. This study focused on the removal and transformation of metformin (MTF), an emerging contaminant in aqueous solutions using a dual biocatalyzed microbial electrosynthesis system (MES). Successful biodegradation of MTF (91 %) was achieved within 120 h with improved bioelectrochemical performance. The current density (−849 mA/m2) with drug loading at 0.5 ppm was 10.3, 7.6, and 2.4 times higher than that of the control, 0.1 ppm, and 0.3, ppm, respectively. Volatile fatty acids (VFAs) production also improved with excellent acetate, propionate, and butyrate production at dual biocatalyzed MES. Liquid chromatography mass spectrometry studies indicated improved mineralization with more MTF bioproducts. MTF regulated the microbial flora through enrichment of the electroactive phyla Proteobacteria and Bacteroidetes. This study provides a new perspective for the use of dual biocatalyzed microbial electrosynthesis systems in bioremediation research.

New Candidates for Biomarkers and Drug Targets of Ischemic Stroke-A First Dynamic LC-MS Human Serum Proteomic Study.

(1) Background: The aim of this dynamic-LC/MS-human-serum-proteomic-study was to identify potential proteins-candidates for biomarkers of acute ischemic stroke, their changes during acute phase of stroke and to define potential novel drug-targets. (2) Methods: A total of 32 patients (29–80 years) with acute ischemic stroke were enrolled to the study. The control group constituted 29 demographically-matched volunteers. Subjects with stroke presented clinical symptoms lasting no longer than 24 h, confirmed by neurological-examination and/or new cerebral ischemia visualized in the CT scans (computed tomography). The analysis of plasma proteome was performed using LC-MS (liquid chromatography–mass spectrometry). (3) Results: Ten proteins with significantly different serum concentrations between groups volunteers were: complement-factor-B, apolipoprotein-A-I, fibronectin, alpha-2-HS-glycoprotein, alpha-1B-glycoprotein, heat-shock-cognate-71kDa protein/heat-shock-related-70kDa-protein-2, thymidine phosphorylase-2, cytoplasmic-tryptophan-tRNA-ligase, ficolin-2, beta-Ala-His-dipeptidase. (4) Conclusions: This is the first dynamic LC-MS study performed on a clinical model which differentiates serum proteome of patients in acute phase of ischemic stroke in time series and compares to control group. Listed proteins should be considered as risk factors, markers of ischemic stroke or potential therapeutic targets. Further clinical validation might define their exact role in differential diagnostics, monitoring the course of the ischemic stroke or specifying them as novel drug targets.

Cover Picture: Liquid Chromatography Mass Spectrometry Study of a Eutectic Mixture of bis(2,2‐Dinitropropyl) Acetal/Formal (Prop., Explos., Pyrotech. 12/2021)

The cover image is based on the Research Article Liquid Chromatography Mass Spectrometry Study of a Eutectic Mixture of bis(2,2-Dinitropropyl) Acetal/Formal by Camille Hing Wong et al., https://doi.org/10.1002/prep.202100189. The Research Article can be found on page 1849 ff.

BREAST CANCER ACTIVITY OF ISOLATED COMPOUND FROM TINOSPORA CORDIFOLIA AERIAL

Objectives: The present study undertaken to explore antioxidant and the cell line study of isolated compound from ethanol extract from Tinospora cordifolia belongs to the family Menispermaceae.
 Methods: The air dried powdered sample of aerial parts of T. cordifolia was extracted in a Soxhlet using five different solvents. Most active ethanol extracts were purified using silica gel column chromatography. Characterized the structure of the isolated compound using Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and liquid chromatography–mass spectrometry studies. Antioxidant and anticancer activity of isolated compound was determined using 2,2-diphenyl-1-picrylhydrazyl and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.
 Results: Magnoflorine was isolated from most active ethanol extract from aerial parts of T. cordifolia which shows maximum antioxidant activity 64% at the tested concentration 500 μg/ml. The percentage of cell viability varied from 53.3% at the minimum tested concentration 3.12 μg/ml to 1.9% at the maximum tested concentration 100 μg/ml.
 Conclusion: The isolated characterized compounds would be useful to prepare plant-based pharmaceutical preparation to treat various diseases linked with human diseases.

Identification, isolation, and structure elucidation of novel forced degradation products of alectinib hydrochloride

AbstractThe present study focuses on novel degradation products of alectinib hydrochloride generated from forced degradation study. In this process, an analytical method was developed that is not only compatible with liquid chromatography–mass spectrometry but sufficiently efficient to capture each of the possible degradation products’ peaks with effective separation from alectinib peak. Alectinib hydrochloride was exposed to acidic, alkali, oxidation, photolytic, and thermal conditions as recommended by the International Conference on Harmonization guidelines. No major degradation was observed under acidic, alkali, photolytic and thermal conditions however the drug was observed to be significantly degraded under oxidative stress conditions generating four novel degradation products that are not reported in the literature. The degradation products were isolated using preparative high‐performance liquid chromatography and then structurally elucidated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and liquid chromatography–mass spectrometry studies. Most importantly, three degradation products were identified as constitutional isomers. The probable degradation products were identified as N‐oxide impurity, epoxide impurity, N‐hydroxy impurity, and amide impurity, respectively. Moreover, pathway of formation of these degradation products was also postulated in detail.

Liquid chromatography–mass spectrometry studies on the isomeric 1-fluorobenzyl-3-naphthoyl-indoles: FUB-JWH-018 and five isomers

One of the ongoing research subjects for forensic analysts is differentiating halogen positional isomers of newly-emerging synthetic cannabinoids. The purpose of this study is to elucidate liquid chromatographic and mass spectrometric conditions applicable to the differentiation of such derivatives. High-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry (QqQ-MS) and linear ion trap time-of-flight mass spectrometry (IT-TOF-MS) using electrospray ionization (ESI) in its positive ion mode were utilized to analyze six model compounds, FUB-JWH-018 and five positional isomers having structures of 1- or 2-naphthoyl-substituted 1H-indole-3-carboxylates with N-substituted positional isomeric fluorobenzyl groups (2-fluorobenzyl, 3-fluorobenzyl, and 4-fluorobenzyl). The chromatographic separation of the six isomers was successfully achieved by HPLC using a pentafluorophenylpropyl-bonded reversed-phase adsorbent. The positive ESI-QqQ-MS could discriminate fluorobenzyl isomers having a same naphthoyl structure via the relative abundance of the two product ions in the collision-induced dissociation reaction. ESI-IT-TOF-MS in its positive ion mode successfully distinguished three ring positional isomers in both naphthoyl scaffolds on the basis of the differences in the abundance of oxomethylium ion attributed to C16H11FNO+ (m/z 252). The use of ESI-QqQ-MS and ESI-IT-TOF-MS in its positive ion mode coupled with LC using a pentafluorophenylpropyl-bonded silica column is applicable to MS-aided differentiation and the chromatographic separation of FUB-JWH-018 positional isomers.

Time Dependency of Chemodiversity and Biosynthetic Pathways: An LC-MS Metabolomic Study of Marine-Sourced Penicillium.

This work aimed at studying metabolome variations of marine fungal strains along their growth to highlight the importance of the parameter “time” for new natural products discovery. An untargeted time-scale metabolomic study has been performed on two different marine-derived Penicillium strains. They were cultivated for 18 days and their crude extracts were analyzed by HPLC-DAD-HRMS (High Performance Liquid Chromatography-Diode Array Detector-High Resolution Mass Spectrometry) each day. With the example of griseofulvin biosynthesis, a pathway shared by both strains, this work provides a new approach to study biosynthetic pathway regulations, which could be applied to other metabolites and more particularly new ones. Moreover, the results of this study emphasize the interest of such an approach for the discovery of new chemical entities. In particular, at every harvesting time, previously undetected features were observed in the LC-MS (Liquid Chromatography-Mass Spectrometry) data. Therefore, harvesting times for metabolite extraction should be performed at different time points to access the hidden metabolome.

Influence of acid chain length on the properties of TiO2 prepared by sol-gel method and LC-MS studies of methylene blue photodegradation

Nano-sized titanium dioxide photocatalysts were synthesized by hybrid hydrolytic nonhydrolytic sol-gel method using aliphatic organic acid templates to study the effect of chain length on their properties. X-ray diffraction pattern indicated crystalline anatase phase. The Barrett-Joyner-Halenda surface area measurement gave surface area ranging from 98.4 to 205.5m2/g and was found to be dependent on the chain length of the aliphatic acid. The longer chain acids rendered the material with high surface area. The organic acids acted as bidentate ligand and a surfactant in controlling the size and the mesoporosity. The size of the TiO2 nanoparticulate was found to be in the range of 10–18nm. The catalyst prepared by employing long chain acids octanoic acid and palmitic acid had smaller size, narrow pore radius, higher surface area and showed better photocatalytic activity than the commercially available Degussa P25 catalyst for the degradation of methylene blue dye. A new intermediate was identified by tandem liquid chromatography mass spectrometry studies during the degradation of methylene blue solution.

Fourier Transform Infrared Spectroscopy and Liquid Chromatography–Mass Spectrometry Study of Extracellular Polymer Substances Produced on Secondary Sludge Fortified with Crude Glycerol

This study was conducted to characterize the extracellular polymeric substances (EPS) produced by growing Cloacibacterium normanense in wastewater sludge alone and fortified crude glycerol. The EPS highest concentration of 17.5 g/L was produced using 25 g/L sludge suspended solids supplemented with 25 g/L of crude glycerol. Galactose and Glucose was the main compound of EPS produced with or without crude glycerol, respectively. EPS FTIR spectra revealed a variation in the different functional groups such as amines, carboxyl, and hydroxyl groups for EPS produced. Different functional groups were observed in the EPS produced with or without glycerol. The EPS exhibited kaolin flocculation activity up to 95% and was stable at high temperature. The high viscosity bioflocculant properties of EPS make it suitable for potential industrial applications

A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies

It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid–liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure.

A study of the effects of exercise on the urinary metabolome using normalisation to individual metabolic output.

Aerobic exercise, in spite of its multi-organ benefit and potent effect on the metabolome, has yet to be investigated comprehensively via an untargeted metabolomics technology. We conducted an exploratory untargeted liquid chromatography mass spectrometry study to investigate the effects of a one-h aerobic exercise session in the urine of three physically active males. Individual urine samples were collected over a 37-h protocol (two pre-exercise and eight post-exercise). Raw data were subjected to a variety of normalization techniques, with the most effective measure dividing each metabolite by the sum response of that metabolite for each individual across the 37-h protocol expressed as a percentage. This allowed the metabolite responses to be plotted on a normalised scale. Our results highlight significant metabolites located in the following systems: purine pathway, tryptophan metabolism, carnitine metabolism, cortisol metabolism, androgen metabolism, amino acid oxidation, as well as metabolites from the gastrointestinal microbiome. Many of the significant changes observed in our pilot investigation mirror previous research studies, of various methodological designs, published within the last 15 years, although they have never been reported at the same time in a single study.

Explanation through density functional theory of the unanticipated loss of CO₂ and differences in mass fragmentation profiles of ritonavir and its rCYP3A4-mediated metabolites.

In the present study, the metabolism of ritonavir was explored in the presence of rCYP3A4 using a well-established strategy involving liquid chromatography-mass spectrometry (LC-MS) tools. A total of six metabolites were formed, of which two were new, not reported earlier as CYP3A4-mediated metabolites. During LC-MS studies, ritonavir was found to fragment through six principal pathways, many of which involved neutral loss of CO2, as indicated through 44-Da difference between masses of the precursors and the product ions. This was unusual as the drug and the precursors were devoid of a terminal carboxylic acid group. Apart from the neutral loss of CO2, marked differences were also observed among the fragmentation pathways of the drug and its metabolites having intact N-methyl moiety as compared to those lacking N-methyl moiety. These unusual fragmentation behaviours were successfully explained through energy distribution profiles by application of the density functional theory.

LC-PDA and LC-MS Studies of Donepezil Hydrochloride Degradation Behaviour in Forced Stress Conditions

The aim of this work was to study the intrinsic stability of donepezil hydrochloride in conditions of forced degradation (acid stress, alkaline stress, oxidant stress, light exposure and dry heat). The degradation profile of donepezil was characterized by liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography coupled with photodiode array detection (LC-PDA). According to the results, the degradation products were separated and detected in acid and alkaline solutions. After seven days at room temperature, the recovery of donepezil in alkaline solution (0.1 mol L-1 NaOH) was about 42%, and three degradation products were detected. In acid solution (0.1 mol L-1 HCl), the drug recovery was about 86%, and three degradation products were detected. Thus, it was possible to propose a rapid and selective stability-indicating assay method using reversed-phase liquid chromatography for analysis of donepezil and their degradation products.

Characterization of a New Anticancer Agent, EAPB0203, and Its Main Metabolites: Nuclear Magnetic Resonance and Liquid Chromatography–Mass Spectrometry Studies

The present study was conducted to assess the structures of the main unknown oxygenated metabolites of EAPB0203. The first step was to assign all the (1)H and (13)C NMR of both EAPB0203 and its demethylated metabolite (EAPB0202) to the corresponding atoms in their molecular structures and to elucidate the fragmentation pathways for the [M + H](+) ions of these compounds using high-resolution mass spectrometry (MS). MS/MS spectra showed that both protonated molecules possessing an even number of electrons were unexpectedly losing radicals such as H(•), CH(3)(•), or even C(7)H(7)(•) giving stable radical cations. In vitro metabolism studies were investigated in rat and dog liver microsomes and in the filamentous fungus Cunninghamella elegans. Structural elucidation of six oxygenated metabolites was performed based on the following: (i) their fragmentation pathways in liquid chromatography-MS/MS (LC-MS/MS) analyses; (ii) comparison of their changes in their molecular masses and fragment ions with those of the parent drugs; and (iii) the results of online H/D exchange experiments that provided additional evidence in differentiating hydoxylated metabolites from N-oxides. Structures of the metabolites were elucidated by LC-MS/MS and comparison with synthetic standards; structures of these standards were confirmed using one- and two-dimensional (1)H NMR spectroscopies.

Gas and liquid chromatography–mass spectrometry studies on the metabolism of the synthetic phenylacetylindole cannabimimetic JWH-250, the psychoactive component of smoking mixtures

Prohibition of some synthetic cannabimimetics (e.g., JWH-018, JWH-073 and CP 47497) in a number of countries has led to a rise in new compounds in herbal mixtures that create marijuana-like psychotropic effects when smoked. The cannabimimetic JWH-250 (1-pentyl-3-(2-methoxyphenylacetyl)indole) was identified in May 2009 by the German Federal Criminal Police as an new ingredient in herbal smoking mixtures. The absence or low presence of the native compound in urine samples collected from persons who had consumed JWH-250 necessitates a detailed identification of their metabolites, which are excreted with urine and present in blood. Using gas and liquid chromatography–mass spectrometry (GC–MS and LC–MS/MS), we identified a series of metabolites in urine samples and serum sample from humans and urine samples from rats that were products of the following reactions: (a) mono- and dihydroxylation of aromatic and aliphatic residues of the parent compound, (b) trihydroxylation and dehydration of the N-alkyl chain, (c) N-dealkylation and (d) N-dealkylation and monohydroxylation. The prevailing urinary metabolites in humans were the monohydroxylated forms, while N-dealkylated and N-dealkyl monohydroxylated forms were found in rats. The detection of the mono- and dihydroxylated metabolites of JWH-250 in urine and serum samples by GC–MS and LC–MS/MS proved to be effective in determining consumption of this drug.