Search

Discovery of drugs rapidly and effectively is an important aspect for Alzheimer's disease (AD). In this study, a novel high-throughput screening (HTS) method aims at screening the small-molecules with amyloid-β (Aβ) binding affinity from natural medicines, based on the combinational use of biolayer interferometry (BLI) and ultra-high-performance liquid chromatography coupled with diode-array detector and quadrupole/time-of-flight tandem mass spectrometry (UHPLC−DAD-Q/TOF-MS/MS) has been firstly developed. Briefly, the components in natural medicines disassociated from biotinylated Aβ were collected to analyze their potential Aβ binding affinity by UHPLC−DAD-Q/TOF-MS/MS. Here, baicalein was confirmed to exhibit the highest binding affinity with Aβ in Scutellaria baicalensis. Moreover, polyporenic acid C (PPAC), dehydrotumulosic acid (DTA), and tumulosic acid (TA) in Kai-Xin-San (KXS) were also identified as potent Aβ inhibitors. Further bioactivity validations indicated that these compounds could inhibit Aβ fibrillation, improve the viability in Aβ-induced PC-12 cells, and decrease the Aβ content and improve the behavioral ability in Caenorhabditis elegans. The molecular docking results confirmed that PPAC, DTA, and TA possessed good binding properties with Aβ. Collectively, the present study has provided a novel and effective HTS method for the identification of natural inhibitors on Aβ fibrillation, which may accelerate the process on anti-AD drugs discovery and development.

In this study, a fully automated two-dimensional liquid chromatography (2D-LC) system was used for the investigation of the clean-up effect and was compared with a traditional Quick Easy Cheap Effective Rugged and Safe (QuEChERS) liquid chromatography (LC) method. The focus of those investigations was on negative electrospray ionization (ESI) mode. For that purpose, matrix fingerprinting profiles were created. The results allowed a comparison of both methods regarding the estimation of the number and the polarity of detected compounds. Moreover, the results of the present study were compared with the results generated in positive ESI mode (presented in a previous study). Furthermore, the two methods were compared with regard to matrix effects (ME) of 321 analytes in positive ESI mode and 96 analytes in negative ESI mode. In general, fewer compounds could be detected when 2D-LC and/or the negative ESI mode was used. Especially, very polar compounds with m/z values >1000 could be separated and could not be detected anymore when 2D-LC was applied. Furthermore, the best results were obtained for most analytes when 2D-LC was used, although the extent of ME seemed to be higher with 2D-LC.

Background: Impurities in pharmaceutical compounds can influence their clinical effects and represent a potential health risk. To ensure the safety and effectiveness of a drug, it is necessary to investigate potential impurities. Methods: In this paper, a new impurity was separated and characterized by two-dimensional high performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry (2D HPLC-Q/TOF-MS) in negative electrospray ionization mode. The peak containing the new impurity, eluted from the first dimension chromatographic system, was selectively trapped by a switching valve based on its retention time and transferred to the second dimension chromatographic system, which was connected to the mass spectrometer. We obtained MET-TA by chemical synthesis, and its structure was characterized by MS/MS and further confirmed by nuclear magnetic resonance (NMR). Results: The impurity was found to be (2S, 3S)-2,3.-dihydroxy-4-((1R,2S)-1-hydroxy-1-(3-hydroxyphenyl) propan-2-yl)amino)-4-oxobutanoic acid, labelled as MET-TA. In this study, we investigated the mechanism of formation of MET-TA, and found that it was the amidation product of metaraminol and tartaric acid. Conclusions: The identification, structural elucidation, synthesis and most probable mechanism of formation of MET-TA are discussed in detail in this paper.

The aroma characteristics of Pu-erh tea were studied in this work. A total of 117 volatile compounds were identified by HS-SPME combined with GC–TOF/MS, of which 29 active aroma compounds were identified by olfactometry. The active aroma compounds of Pu-erh tea were analyzed by intensity aroma (IA), aroma extraction dilution (AEDA), sensory quantification value (MF), detection frequency (DFA) and odor activity value (OAV). 24, 21 and 23 active aroma components were identified by DFA, AEDA and OAV, while 20 by IA and MF. Recombination of the obtained active aroma components indicated that OAV method was best for determining the active aroma compounds as the aroma profile of OAV recombination model was the most similar to that of Pu-erh tea sample. Omission test of the OAV recombination model furtherly identified 19 characteristic active aroma compounds of Pu-erh tea, and linalool, 1,2,3-trimenthoxybenzebe, 1,2,4-trimethoxybenzene and ɑ-ionone were the key characteristic active aromatic compounds.

Background Red ginseng polysaccharides (RGPs) have been acknowledged for their outstanding immunomodulation and anti-tumor activities. However, their studies are still limited by the complexity of their structural features, the absence of purification and enrichment methods, and the rarity of the analytical instruments that apply to the analysis of such macromolecules. Thus, this study is an attempt to establish a new mass spectrometry (MS)-based analysis procedure for RGPs. Methods Saponin pre-excluded powder of RG (RG-SPEP, 10 mg) was treated with 200 μL of distilled water and centrifuged for 5 h at 1000 rpm and 85 °C. Ethanol-based precipitation and centrifugation were applied to obtain RGPs from the heated extracts. Further, endo-carbohydrase treatments were performed to produce specific saccharide fragments. Solid-phase extraction (SPE) processes were implemented to purify and enrich the enzyme-treated RGPs, while matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) MS was employed for the partial structural analysis of the obtained RGPs. Results Utilizing cellulase, porous graphitized carbon (PGC), hydrophilic interaction chromatography (HILIC), and MALDI-TOF/TOF MS, the neutral and acidic RGPs were qualitatively analyzed. Hexn and Hexn−18 (cellulose analogs) were determined to be novel neutral RGPs. Additionally, the [Unknown + Hexn] species were also determined as new acidic RGPs. Furthermore, HexAn (H) was determined as another form of the acidic RGPs. Conclusion Compared to the previous methods of analysis, these unprecedented applications of HILIC-SPE and MALDI-TOF/TOF MS to analyze RGPs proved to be fairly effective for fractionating and detecting neutral and acidic components. This new procedure exhibits great potential as a specific tool for searching and determining various polysaccharides in many herbal medicines., Graphical abstract Image 1

Objective Validation of a non-targeted method for urine drug screening (UDS) by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF), and comparison to an established GC–MS method in a hospital setting. Methods 217 UDS specimens sent to a quaternary hospital pathology department, were analysed by a CEDIA® immunoassay screen (six drug panels; amphetamines , barbiturates, benzodiazepines , cocaine metabolites, cannabinoids and opiates) on an Abbott Architect instrument. Specimens were subsequently analysed by an established non-targeted qualitative GC–MS method and results compared with a general unknown screening method by LC-QTOF that was under evaluation as a replacement method. Results 42 selected drugs were evaluated; limits of identification ranged from 2 to 100 µg/L and most drugs (n = 39) were stabile for 24 h after preparation. Matrix effects greater than 25% were observed in seven of the selected drugs. 87% of the specimens tested positive to 1 or more drug panels in a CEDIA® screen. A total of 537 positive drug findings were identified by GC–MS compared to 1,267 positive findings by LC-QTOF. On average, each GC–MS screen identified 2.5 ± 1.8 drugs and the LC-QTOF screen identified 5.8 ± 3.2 drugs. No drugs were identified in 11.3% of the GC–MS screens, whereas drugs were detected in 99% of these by the LC-QTOF. In almost all instances, the LC-QTOF screen could provide mass spectrometric confirmatory results of positive immunoassay screens and was able to identify a wider range of additional drugs and drug metabolites . Conclusions The described general unknown screening (non-targeted, qualitative) LC-QTOF method can detect a larger range of drugs encountered in a hospital setting. The method has been shown to be suitable for comprehensive toxicology screening in a clinical toxicology laboratory.

A novel stability-indicating HPLC method for the quantitative determination of impurities in meropenem raw material was established and fully validated for the further improvement of the official monograph in Pharmacopeia. The method was carried out on a Shim-Pack CLC-ODS column with UV detection at 220 nm. The influences of different band columns, composition ratio of mobile phase, gradient elution procedure, and pH value of mobile phase on separation of impurities in meropenem were investigated. The parameters specificity, precision, linearity, range, accuracy, limit of detection, limit of quantitation, and robustness were studied according to the regulatory guidelines recommended by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). The linear regression analysis results of EP impurity A and EP impurity B show that there is a good linear relationship between response and concentration, and the correlation coefficients are 0.9999 and 1.0000, respectively. The accuracy of EP impurity A and EP impurity B is between 90 and 104%. Through analysis, the LOD and LOQ values of EP impurities A and B were measured and found to be 0.22 and 0.74 µg mL-1, respectively. Moreover, three unknown degradation impurities in meropenem were identified by two-dimensional liquid chromatography tandem with high-resolution ion trap/time-of-flight mass spectrometry in electrospray ionization mode. Compared with the current method in Pharmacopeia, the developed method had greatly improved the separation and detection ability of impurities. The established method was highly specific, sensitive, and accurate for reliable routine quality control of meropenem raw material. The structures of unknown impurities were characterized based on the MS/MS data.

Background: Indobufen is a drug that hinders the aggregation of platelets by reversibly repressing the cyclooxygenase enzyme, further bringing about diminished thromboxane production. During quality control of indobufen tablets, an unknown impurity was detected. Objective: To characterize an unknown impurity in indobufen tablets. Methods: A new method compatible with mass spectrometry detection was set up. A C18 column at 35 °C with a mobile phase consisting of aqueous buffer (including ammonium formate) and methanol (35: 65, v/v) was used at a flow rate of 1.0 mL/min at 228 nm. High-performance liquid chromatography quadrupole time-of-flight mass spectrometry mass spectrometry (HPLC-Q-TOF MS) was used to identify the impurity with the electrospray ionization (ESI) source in the positive ionization mode. Results: The results of HPLC-Q-TOF MS analysis indicated that the protonated molecule ions [M + H]+ of the unknown impurity was at m/z 312. Preparative LC method was put into practice with a Prep- C18 column with a mobile phase consisting of water and methanol (20: 80, v/v) at a flow rate of 20.0 mL/min at 228 nm. The assignment of the 1D and 2D NMR signals was performed for the unknown impurity. In addition, possible formation of the novel impurity was also studied. Conclusion: An unknown impurity in indobufen tablets was characterized. The impurity was assigned as 2-(4-(1-hydroxy-3-oxoisoindolin-2-yl) phenyl) butanoic acid.

Lipophilic marine biotoxins azaspiracids (AZAs) are produced by dinoflagellates Azadinium and Amphidoma. Recently, several strains of Azadinium poporum were isolated from Japanese coastal waters. In our present study, AZA analogues in two strains (mdd421 and HM536) of A. poporum were analyzed by several detection techniques on the liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOFMS). The dominant AZA analogue in the Japanese A. poporum strains was AZA2. Other known AZA analogues were AZA11, AZA35, AZA2 methyl ester and AZA2 phosphate ester. Besides these AZAs, thirteen new AZA analogues were discovered in the two strains. A putative AZA analogue (Compound 1) with the smallest molecular weight ever found in nature was also discovered in the two strains. This is the first report describing detailed AZA profiles in Japanese isolates of A. poporum.

Illicit drug profiling performed by forensic laboratories assists law enforcement agencies through providing information about chemical and/or physical characteristics of seized specimens. In this article, a model was developed for the comparison of seized cocaine based on retrospective analysis of data generated from ultrahigh performance liquid chromatography with time-of-flight mass spectrometry (UHPLC-TOF-MS) comprehensive drug screening. A nontargeted approach to discover target compounds was employed, which generated 53 potential markers using data from cocaine positive samples. Twelve marker compounds were selected for the development of the final profiling model. The selection included a mixture of commonly used cocaine profiling targets and other cocaine-related compounds. Combinations of pretreatments and comparison metrics were assessed using receiver operating characteristic curves to determine the combination with the best discrimination between linked and unlinked populations. Using data from 382 linked and 34,519 unlinked distances, a classification model was developed using a combination of the standardization and normalization transformations with Canberra distance, resulting in a linked cut-off with a 0.5% false positive rate. The present study demonstrates the applicability of retrospectively developing a cocaine profiling model using data generated from UHPLC-TOF-MS nontargeted drug screening without pre-existing information about cocaine impurities. The developed workflow was not specific to cocaine and thus could potentially be applied to any seized drug in which there are both sufficient data and impurities present.

Mutan is an extracellular sticky polymer having α-1-3 and α-1-6 glycosidic linkages with a large diversity in molecular weights and structures depending on the source. These compounds are reported to be highly thermostable and also have potential physiochemical and biological applications. The main aim of this review is to provide an overview of glucosyltransferases and their role in mutan synthesis. The production strategies and structural properties of bacterial mutans are discussed with a goal to improve production efficiency. The physicochemical features, chemical modifications, potential industrial applications and future prospects are also discussed. According to data, mutan and its derivatives will play a larger role in medicinal sectors and as thermoplastics in the near future.Abbreviations: ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid; BHI: Brain heart infusion broth; 13C (HSQC) NMR: Heteronuclear Single Quantum Coherence NMR; CBMs: Carbohydrate binding modules; DPPH: 2,2-diphenyl-1-picrylhydrazyl; FTIR: Fourier-transform infrared spectroscopy; GC-MS: Gas chromatography-mass spectrometry; GPC: Gel permeation chromatography; Gtfs: Glucosyltransferases; 1H (DQF-COSY): Double-quantum filtered correlation spectroscopy; HPAEC-PAD: High-performance anion exchange chromatography with pulsed amperometric detection; HPLC: High performance liquid chromatography; HPSEC-RI: High-performance size exclusive chromatography coupled with refractive index; HPSEC-MALLS: High-performance size exclusive chromatography with multi-angle laser light scattering detection; MALDI-TOF: Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry; Mw: Weight-average molecular weight; MWD: Molecular weight distribution; NMR: Nuclear magnetic resonance spectroscopy; TEM: Transmission electron microscopy; THB: Todd Hewitt Broth; TTY: Tryticase tryptose yeast extract broth.

Honey varies depending on plant origin and environmental conditions. Chemical constituents can be used to determine the origins, characteristics, and storage period of a specific honey. Styrax japonica (snowbell) honey has excellent flavor, but very few studies have been carried out on its chemical constituents. Therefore, the present study was aimed to identify chemical constituents containing in snowbell honey and to screen candidate marker compounds for predicting the storage period of snowbell honey using the identified compounds. Twelve compounds including three new compounds were purified and isolated from the snowbell honey. Three new compounds were elucidated as 1α,3β,5β-bornetriol, 7-hydroxy-2,2,6-trimethyl-1-oxaspiro[2.5]oct-5-en-4-one, and 2-benzyl-2,3-dihydroxybutanoic acid, based on ESI-MS and NMR experiments. 6,7-Dihydroxylinalool and 6,7-dihydroxygeraniol isolated as known compounds in this study were identified for the first time in snowbell honey as well as in other honeys. The isolated compounds were qualified and quantified by LC-ESI-Q-TOF-MS/MS analysis. All compounds were detected in snowbell honeys of different production years. The levels of tyrosol, 7-hydroxy-2,2,6-trimethyl-1-oxaspiro[2.5]oct-5-en-4-one, and (–)-dihydroxyphaseic acid were lower in snowbell honey with long storage period than in short storage period, which is suggested to be used as candidate marker compounds for predicting the storage period of snowbell honey.

20-Hydroxyecdysone (20E) derived from plants has a wide range of physiological and pharmacological effects on animals and humans, and rapid and sensitive methods for screening of the endogenous 20E in plants are thus required. Herein, a matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS) method is described for rapid and sensitive determination of endogenous 20E in plants. It is based on the use of the (3-(acridin-9-ylamino) phenyl) boronic acid (AYPBA) as the mass tag to assist the MS and tandem MS (MSn) analysis of 20E on MALDI-TOF/TOF MS. Good linearity was obtained with a determination coefficient (R2) larger than 0.99 in the range of 0.025–2.5 μΜ. The limit of detection (LOD) was 2.4 fmol. Acceptable precision and accuracy were gained by intra- and inter-day analysis with relative standard deviations less than 19.5% and relative recoveries ranging from 85.7 to 105.2%. In addition, the AYPBA labeled 20E produced abundant characteristic fragment ions under the high energy collision-induced dissociation, which facilitated the identification of 20E by MS2 analysis on MALDI-TOF/TOF MS. Using the method, we enabled the identification and quantification of endogenous 20E in four herbs including Cyanotis arachoidea, Achyranthes bidentata, Spinacia oleracea and Chenopodium quinoa willd., demonstrating the feasibility of the proposed method for screening of the endogenous 20E in plants.

Introduction A wide array of alternative nicotine delivery devices (ANDD) has been developed and they are often described as less harmful than combustible cigarettes. This work compares the chemical emissions of three ANDD in comparison to cigarette smoke. All the tested ANDD are characterized by not involving combustion of tobacco. Aims and Methods Single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) is coupled to a linear smoking machine, which allows a comprehensive, online analysis of the gaseous phase of the ANDD aerosol and the conventional cigarette (CC) smoke. The following devices were investigated in this study: a tobacco cigarette with a glowing piece of coal as a heating source, an electric device for heating tobacco, and a first-generation electronic cigarette. Data obtained from a standard 2R4F research cigarette are taken as a reference. Results The puff-by-puff profile of all products was recorded. The ANDD show a substantial reduction or complete absence of known harmful and potentially harmful substances compared with the CC. In addition, tar substances (i.e. semivolatile and low volatile aromatic and phenolic compounds) are formed to a much lower extent. Nicotine, however, is supplied in comparable amounts except for the investigated electronic cigarette. Conclusions The data show that consumers switching from CC to ANDD are exposed to lower concentrations of harmful and potentially harmful substances. However, toxicological and epidemiological studies must deliver conclusive results if these reduced exposures are beneficial for users. Implications The comparison of puff-resolved profiles of emissions from different tobacco products, traditional and alternative, may help users switch to lower emission products. Puff-resolved comparison overcomes technical changes, use modes between products and may help in their regulation.

Rhizoma Anemarrhenae is a well-known herbal medicine with saponins as its commonly regarded major bioactive components. It is essential to classify the properties of saponins which are associated with their toxicity and efficacy. In this study, 25 compounds were identified by HPLC-Q-TOF/MS in the extract of Rhizoma Anemarrhenae and 8 saponins were detected in rat plasma by HPLC-MS/MS after oral administration of this extract. These were neomangiferin, mangiferin, timosaponin E1, timosaponin E, timosaponin B-II, timosaponin B-III, timosaponin A-III and timosaponin A-I. A sensitive and accurate HPLC-MS/MS method was developed and successfully applied to a pharmacokinetic study of the abovementioned eight saponins after oral administration of the Rhizoma Anemarrhenae extract to rats. The method validation, including specificity, linearity, precision, accuracy, recovery, matrix effect and robustness, met the requirements of the intended use. The pharmacokinetic parameter, T max value, ranged from 2 to 8 h for these eight saponins whereas their elimination half-life (t 1/2) ranged from 4.06 to 9.77 h, indicating slow excretion. The plasma concentrations of these eight saponins were all very low, indicating a relatively low oral bioavailability. All these results provide support for further clinical studies.

Objectives The present study was conducted to evaluate the usefulness of capillary electrophoresis (CE), cation-exchange high-performance liquid chromatography (HPLC), and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) for the screening of hemoglobin (Hb) variants prevalent in southern China. Methods A total of 102 types of Hb variants in 1,083 variant carriers were identified over a 5-year period. These variants were analyzed by a CE method (Capillarys 3 TERA), a cation-exchange HPLC analyzer (Variant II Turbo 2.0), and a MALDI-TOF MS system (QuanTOF). Results The presence of 85 (83.3%, 85/102), 84 (82.4%, 84/102), and 62 (60.8%, 62/102) Hb variants was detected by Capillarys 3 TERA, Variant II Turbo 2.0, and QuanTOF, respectively. Of the three methods, only Capillarys 3 TERA recognized all 10 of the most frequent Hb variants in southern China. There were six, two, and three Hb variants that can only be detected by Capillarys 3 TERA, Variant II Turbo 2.0, and QuanTOF, respectively. The detection limit of mass difference for QuanTOF was approximately 11 to 20 Da. Conclusions MALDI-TOF MS is suitable for use as an auxiliary method rather than a stand-alone method for the screening of Hb variants prevalent in southern China.

Aim To purify Cryptosporidium spp. oocysts from clinical stool samples and evaluate using an up-to-date mass spectrometry protocol producing high-quality reference spectra. Methods and results A refined purification protocol was developed for oocysts from stools, involving salt flotation and potassium bromide density centrifugation. Purified oocysts were prepared for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by formic acid extraction, and the extracts analysed using the Bruker MALDI Biotyper system. Individual spectral markers were identified by their specific mass peaks. Cryptosporidium parvum oocysts (Iowa strain) propagated in vivo, and C. parvum (n = 2) and Cryptosporidium hominis (n = 1) oocysts from clinical stool samples produced distinct spectra that were considered specific to Cryptosporidium spp. with no evidence of contamination. Conclusions The production of distinct spectra demonstrated the utility of the purification method for oocysts from clinical stool samples and provided reference spectra. Significance and impact of the study The use of MALDI-TOF MS and other mass spectrometry techniques has been limited previously to C. parvum oocysts propagated in vivo. Appropriate purification of oocysts can achieve sufficient biomass, enabling analysis by MALDI-TOF MS and potentially other mass spectrometry platforms, facilitating peptide and protein discovery and identification of biomarkers from a much wider range of Cryptosporidium spp. from natural infections.

Analysis and identification of seized doping-related products are important tasks for customs or forensic laboratories in order to prevent potentially dangerous and illegal compounds to go into circulation. At the Section of Forensic Chemistry in Copenhagen, we have a workflow consisting of four complimentary validated methods to identify common doping-related substances: liquid chromatography-ultraviolet (LC-UV), LC coupled with time of flight mass spectrometry (LC-TOF-MS), the colorimetric Bradford assay, and an immunoassay. The Bradford assay screens for peptide or proteins in the sample, and the immunoassay confirmed human chorionic gonadotropin (hCG). LC-UV was carried out with a C4 protein column for identification of peptides and proteins from a standard reference library, based on retention times and ratios between peak areas at 220, 254, and 280 nm. LC-TOF-MS was performed using a C18 column, and identification was based on comparison of the retention time and the accurate mass with those of reference standards. In 2019, we received 36 samples for peptide/protein analysis, all of which were tested using the LC-UV, LC-TOF-MS, and colorimetric method, and samples suspected of containing hCG were confirmed with an immunoassay. We found a total of 15 samples containing an illegal doping substance, 12 samples containing substances not prohibited by the Danish Doping List, and nine samples containing no peptides or proteins. In conclusion, the four complimentary methods constitute a suitable approach for identifying common peptide/protein doping substances in the day-to-day routine of a forensic laboratory, with limited sample preparation and interpretation of data.

Graphical abstract Traditional Chinese medicines played an important role in the treatment of COVID-19 in 2020. Ephedra sinica, one of the major constituent herbs of multi-component herbal formula, has been widely used to treat COVID-19 in China. However, its active components are still unclear. The objectives of this study are to screen and evaluate active components from the traditional Chinese medicine Ephedra sinica for the treatment of COVID-19. In our study, we established an ACE2/CMC bioaffinity chromatography model, and then developed an ACE2/CMC-HPLC-IT-TOF-MS system for the active compounds screening and identification from Ephedra sinica extract. We performed molecular docking and surface plasmon resonance (SPR) assays to assess the binding characteristics (binding mode and KD value). We used CCK-8 staining to assess the toxicity of screened compounds, and also used SARS-CoV-2 pseudovirus to observe the viropexis effect of screened compounds in ACE2h cells. In this current work, one fraction was fished out, separated and identified as ephedrine (EP), pseudoephedrine (PEP), and methylephedrine (MEP). Binding assays showed that the three compounds could bind with ACE2 in a special way to some amino acid residues, similar to the way SARS-CoV-2 bound with ACE2. Additionally, the three compounds, especially EP, can inhibit the entrance of SARS-CoV-2 spike pseudovirus into ACE2h cells because they can reduce the entrance ratio of pseudovirus in the pseudovirus model. Overall, the ACE2/CMC-HPLC-IT-TOF-MS system was established and verified to be suitable for ACE2-targeted bioactive compound screening. EP, PEP, and MEP with ACE2-binding features were screened out from Ephedra sinica, and acted as blockers inhibiting SARS-CoV-2 spike pseudovirus entering ACE2h cells. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03233-7.

Pu-erh tea is believed to be a beneficial beverage for health due to its many kinds of pharmacological effects. Nevertheless, detailed information related to differences in metabolites of Pu-erh raw tea from different geographical origins remains scarce. In this study, 43 elements were found in water-soluble components of Pu-erh raw tea by highly sensitive ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (U-HPLC/Q-TOF-MS). The characteristic groups of 29 metabolites from nondestructive proton nuclear magnetic resonance (1 H-NMR) spectroscopy were assigned. The variables contributed largely to the origin classification, mainly including valine, threonine, chlorogenic acid, quinic acid, epiafzelechin, and gallic acid ester, were screened out by sparse partial least squares discriminant analysis (sPLS-DA) method. This study provided a feasible and rapid technique for distinguishing Pu-erh tea from different areas by 1 H-NMR combined with sPLS-DA.

Syneilesis palmata (S. palmata) is a common Korean therapeutic herb extensively used to treat pain. The species Paris verticillata (P. verticillata) is morphologically similar to S. palmata but wit...

1. Chemical sensing in vertebrates is crucial in their lives, and efforts are undertaken towards deciphering their chemical language. Volatile organic compounds (VOCs) are a group of chemicals believed to play an essential role in a wide variety of animal interactions. Therefore, understanding what animals sense themselves and untangling the ecological role of their volatile cues can be accomplished by analysing VOC emissions. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) is an instrument that measures VOCs in real-time in an air sample. Since this technique acts as a hyper-sensitive 'nose' it has a similar potential in deciphering the chemical language of vertebrates. 2. Here, we validate the use of PTR-TOF-MS as a tool to measure VOCs from vertebrates, which in turn will help resolve vertebrate interactions through VOCs. The instrument monitors and records the full spectrum of VOCs emitted by an individual with a high accuracy and low detection limit, including transient VOC emissions. We propose and test diverse measuring configurations that allow for measurement of VOC emissions from different vertebrates and their exudates: full body, specific parts of the body, urine and femoral pores. In addition, we test configurations for sudden and short-lasting processes as VOCs emitted during adder skin shedding as well as the emissions of skin secretions upon mechanical and physiological stimulation in amphibia. Our configurations work in tandem with gas chromatography-mass spectrometry (GC-MS) to allow compound structure verification. 3. We discuss the configurations and methodologies used and conclude with recommendations for further studies, such as the choice of chamber size and flow. We also report the results of the measurements on vertebrates-that are novel to science-and discuss their ecological meaning. 4. We argue that PTR-TOF-MS has a high potential to resolve important unanswered questions in vertebrate chemical ecology with great adaptability to a wide range of experimental set-ups. If combined with a structure verification tool, such as GC-MS, the creative deployment of PTR-TOF-MS in various future study designs will lead to the identification of ecologically relevant VOCs.

Staining of biological cells with heavy metals can increase their visibility in mass spectrometry. In this study, the potential of ruthenium red (RR) as a staining agent for single-cell analysis by inductively coupled plasma time-of-flight mass spectrometry (SC-ICP-TOF-MS) is explored using two different yeast strains and one algal species. Time-of-flight mass spectrometry allows the simultaneous detection of Ru and multiple intrinsic elements in single cells. Ru has a better correlation with Mg than with P in Saccharomyces cerevisiae (S. cerevisiae) cells. For the three tested strains, the staining efficiency of RR exceeded 96%; the staining strengths were 30-32 ag μm-2 for the yeast cells and 59 ag μm-2 for the algal cells. By deriving the cell volume of single cells from their Ru mass, the concentration of Mg and P in individual cells of S. cerevisiae can be calculated. Elemental concentrations of Mg and P were highly variable in the cell individuals, with their 25-75 percentile values of 0.10-0.19 and 0.76-2.07 fg μm-3, respectively. RR staining has several advantages: it is fast, does not affect cell viability and is highly efficient. Provided that the shape of the individual cells of a culture is similar, Ru staining allows the elemental content to be directly correlated with the cell volume to accurately calculate the intracellular concentration of target elements in single cells. Therefore, RR can be a promising cell staining agent for future application in SC-ICP-TOF-MS research.

Perillae Folium (PF), which is extensively used as a dietary vegetable and medicinal herb, contains two varietal forms corresponding to purple perilla leaf (Perilla frutescens var. crispa) and green perilla leaf (Perilla frutescens var. frutescens). However, the components and efficacy of different PF varieties remain underexplored so far. In the present work, a nontargeted rapid resolution liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (RRLC-Q/TOF-MS)-based metabolomics approach was developed to investigate the difference in the chemical compositions between green PF and purple PF. A total of 71 compounds were identified or tentatively identified, among which 7 phenolic acids, 10 flavonoids, and 9 anthocyanins were characterized as differential metabolites. In addition, heatmap visualization and ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-TQ-MS/MS)-based quantitative analysis revealed that flavonoids and anthocyanins especially had higher contents in purple PF. Furthermore, the anti-oxidative activities of two varietal PFs were evaluated in vivo zebrafish and in vitro human umbilical vein endothelial cells (HUVECs). The results showed that the purple PF had more pronounced anti-oxidative activities than did the green PF, which may be due to the presence of anthocyanins and a higher concentration of flavonoids in its phytochemical profile. The outcome of the present study is expected to provide useful insight on the comprehensive utilization of a PF resource.

The combination of ultra-high-performance liquid chromatography (UHPLC) with time-of-flight mass spectrometry (ToF-MS) is one of the most powerful analytical tools in terms of selectivity, sensitivity and speed. However, due to the gap on regulation and guidelines concerning the validation criteria for the use of ToF-MS methodology not only for screening but also for confirmatory and quantification purposes, this study presents, for the first time, an approach on how to use the referred methodology for confirmatory and quantification purposes. Thus, an UHPLC-ToF-MS method was developed and validated for the simultaneous determination of 43 antibiotic residues from 7 different families (tetracyclines, sulfonamides, quinolones, penicillins, macrolides, cephalosporins and trimethoprim) in piglet kidneys as a confirmatory method. A simple sample preparation consisting of extraction with a mixture of acetonitrile and ethylenediaminetetraacetic acid (EDTA) followed by solid-phase extraction (SPE) with a hydrophilic-lipophilic balanced (HLB) cartridge and finalized with a defatting step with n-hexane was used. The methodology was validated according the Commission Decision 2002/657/EC, by defining suitable criteria for antibiotic identification, as well as by evaluating required parameters like selectivity, specificity and ruggedness that fulfil the required criteria. The calculated values of decision limit (CCα) and of detection capacity (CCβ) for antibiotics with established maximum residue limits (MRLs) fully complied with required criteria. For antibiotics for which no MRL was set, values ranging from 0.2 to 0.5 μg kg−1 and from 0.5 to 0.8 μg kg−1 were achieved for CCα and for CCβ, respectively. Linearity (all R2 > 0.95), recovery (81.4–110.0%) (lowest values of 4.6% and 7.1% were obtained for repeatability and for reproducibility, respectively), LODs (0.04–13.0 μg kg−1), LOQs (0.09–32.0 μg kg−1) and matrix effects (35.5–118.1 %) were also evaluated. After validation, the method was applied to analyse piglet kidney samples. Antibiotic residues were determined in 10 of the 15 analysed samples. However, all the antibiotics concentrations were below the MRLs.

Some secondary metabolites produced by fungi are carcinogenic, hepatotoxic, and/or cause birth defects in humans and animals. We developed and optimised bio-analytical tools for detection of metabo...

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is an established tool in drug development, which enables visualization of drugs and drug metabolites at spatial localizations in tissue sections from different organs. However, robust and accurate quantitation by MALDI-MSI still remains a challenge. We present a quantitative MALDI-MSI method using two instruments with different types of mass analyzers, i.e., time-of-flight (TOF) and Fourier transform ion cyclotron resonance (FTICR) MS, for mapping levels of the in vivo-administered drug citalopram, a selective serotonin reuptake inhibitor, in mouse brain tissue sections. Six different methods for applying calibration standards and an internal standard were evaluated. The optimized method was validated according to authorities' guidelines and requirements, including selectivity, accuracy, precision, recovery, calibration curve, sensitivity, reproducibility, and stability parameters. We showed that applying a dilution series of calibration standards followed by a homogeneously applied, stable, isotopically labeled standard for normalization and a matrix on top of the tissue section yielded similar results to those from the reference method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The validation results were within specified limits and the brain concentrations for TOF MS (51.1 +/- 4.4 pmol/mg) and FTICR MS (56.9 +/- 6.0 pmol/mg) did not significantly differ from those of the cross-validated LC-MS/MS method (55.0 +/- 4.9 pmol/mg). The effect of in vivo citalopram administration on the serotonin neurotransmitter system was studied in the hippocampus, a brain region that is the principal target of the serotonergic afferents along with the limbic system, and it was shown that serotonin was significantly increased (2-fold), but its metabolite 5-hydroxyindoleacetic acid was not. This study makes a substantial step toward establishing MALDI-MSI as a fully quantitative validated method.

Dynamic pressure gradient modulation (DPGM) in full modulation mode is optimized for comprehensive two-dimensional (2D) gas chromatography (GC × GC) with time-of-fight mass spectrometry (TOFMS) detection to obtain high peak capacity separations and demonstrate broad applicability for complex samples. A pulse valve introduces an auxiliary carrier gas flow at a T-union connecting the first dimension (1D) column to the second dimension (2D) column. At a sufficiently high auxiliary pressure (Paux) the 1D flow is temporarily stopped. Then, during each modulation period (PM) the valve is turned off briefly, a period termed the pulse width (pw), allowing the 1D effluent to essentially be reinjected onto the 2D column for the modulated separations. Modifications to the modulator assembly are provided to improve performance. Method optimization is demonstrated for a 116-component test mixture by tuning the Paux and the pw. For a PM = 2 s and 1F of 0.10 ml/min, the optimal pw and initial Paux selected were 200 ms and 330.9 kPa (33 psig), respectively. The 30 min separation of the test mixture provided a 1D peak capacity of 1nc = 330 and a 2D peak capacity of 2nc = 15, hence an ideal 2D peak capacity nc,2D = 1nc × 2nc = 4950. Likewise, the 2D peak capacity corrected for undersampling of the 1D separation was 4500 and corrected for both undersampling and sampling variation via statistical overlap theory was 4090. These results provide a 2-fold improvement in peak capacity relative to the previous DPGM study in full modulation mode for GC × GC-TOFMS. The optimized conditions were applied for a variety of applications: diesel fuel, derivatized cow serum, solid phase microextraction (SPME) of coffee headspace, and SPME of river water headspace. Additionally, the fraction of 2D separation space utilized (fcoverage), as defined by the minimum convex hull method, ranged from 0.60 to 0.85. We observed that any fcoverage correction to 2D peak capacity is highly sample dependent, since all samples, except for the diesel sample, were run with the same separation conditions, and yet the fcoverage ranged from 0.60 to 0.80.

The use of uncontrolled toxic concentrations of systemic insecticides belonging to the class of neonicotinoids in agriculture has a negative impact on the life of honeybees. The situation is aggravated by the fact that compared to other pesticides, neonicotinoids have acute toxicity to bees, contributing to their death. This paper presents a developed multimethod for qualitative and quantitative determination of certain lethal bee intoxicants of a number of neonicotinoids: thiamethoxam, clothianidin, Imidacloprid and acetamiprid by high–performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (HPLC-MS/MS). Sample preparation for HPLC-MS/MS was carried out using a modified QuEChERS method, followed by post-treatment of samples by dispersion solid-phase extraction (TFE). Chromatographic separation was performed by gradient reverse-phase HPLC, detecting neonicotinoids in the multiple reaction monitoring (MRM) mode. The assessment and verification of the completeness of the degree of recovery of neonicotinoids by the modified version of QuEChERS, based on the results of HPLC-MS/MS definitions, indicate that a high degree of their recovery has been achieved. Under the proposed conditions of chromatographic separation, the analytical signals of the determined neonicotinoids are characterized by correlation coefficients (r2) equal to 0.999. The limits of detection (3·Sa/b) of neonicotinoids detected under HPLC-MS/MS conditions are established, which are: 1.6.10-3 mg/kg of thiamethoxam and Imidacloprid; 1.8.10-3 mg/kg of acetamiprid and 1.9.10-3 mg/kg of clothianidine. The developed HPLC-MS/MS multimethod is used for screening the material of dead bees for neonicotinoids, which are their lethal intoxicants.

Sphingomyelin (SM) with N-α-hydroxy fatty acyl residues (hSM) has been shown to occur in mammalian skin and digestive epithelia. However, the metabolism and physiological relevance of this characteristic SM species have not been fully elucidated yet. Here, we show methods for mass spectrometric characterization and quantification of hSM. The hSM in mouse skin was isolated by TLC. The hydroxy hexadecanoyl residue was confirmed by electron impact ionization-induced fragmentation in gas chromatography-mass spectrometry. Mass shift analysis of acetylated hSM by time of flight mass spectrometry revealed the number of hydroxyl groups in the molecule. After correcting the difference in detection efficacy, hSM in mouse skin and intestinal mucosa were quantified by liquid chromatography-tandem mass spectrometry, and found to be 16.5 ± 2.0 and 0.8 ± 0.4 nmol/μmol phospholipid, respectively. The methods described here are applicable to biological experiments on hSM in epithelia of the body surface and digestive tract.

Objectives This study was designed to profile the chemical information of Forsythiae Fructus (FF) and investigate the in-vivo FF-related xenobiotics, especially for lignans. Methods Rats were oral administrated of FF and pinoresinol-4-O-glucoside, respectively. Blood and urine samples were collected after ingestion, and xenobiotics was profiled by an UPLC/Qtof MS method. Key findings A total of 19 lignans were identified or tentatively characterized in FF, and 63 lignan-related xenobiotics were found in rat plasma and urine after ingestion of FF. It was found that lignans could be transformed into metabolites by furan ring opening, hydrogenation, demethylation, dehydration and phase II reactions (sulfation and glucuronidation). The whole metabolic behaviour of bisepoxylignan was revealed by evaluating the metabolism of pinoresinol-4-O-glucoside in vivo. It was found that the configuration of C-8/C-8ʹ was retained after furan ring opening and metabolic reactions always occurred at position of C-3/C-4/C-5 or C-3ʹ/C-4ʹ/C-5ʹ. Additionally, other types components in FF and in vivo were also characterized. Conclusions This work revealed the in-vivo metabolism of FF, and reported the characteristic metabolic reactions of lignans for the first time. It was also provided the foundation for the further investigation on pharmacodynamic components of FF or TCMs containing FF.

Nafamostat mesylate is a serine protease inhibitor used in the treatment of acute pancreatitis. The impurities in nafamostat mesylate, the active pharmaceutical ingredient (API), were profiled via high performance liquid chromatography tandem ion trap coupled with time-of-flight mass spectrometer (HPLC-IT-TOF/MS). The chromatography was performed on an ACE-3 C18 column (200 mm × 4.6 mm, 3 μm) using methanol and 0.1% formic acid in purified water as mobile phase at a flow rate of 1.0 mL/min. The ions were detected by IT-TOF/MS with a full-scan mass analysis from m/z 100 to 800. In total, eleven impurities were detected in nafamostat mesylate API. The impurity profile was estimated based on the HPLC-IT-TOF/MS data, including accurate masses, MSn fingerprints of fragmentation pathways and a series of double-charged ions. Finally, seven impurities were identified and reported for the first time. The results will provide technical support for the quality control and clinical safety of nafamostat mesylate., Graphical abstract Image 1, Highlights • An HPLC-IT-TOF/MS method for the separation and identification of impurities in nafamostat mesylate was developed. • The impurities were identified based on the particular structural characteristics of nafamostat. • Seven impurities containing in nafamostat mesylate were reported for the first time.

As one of the three most famous brewed wines in the world, Chinese rice wine is made from rice and husked millet, containing 14 percent to 20 percent alcohol. Highly original, yellow wine brewing techniques are regarded as the model of the wine brewing industry in Asia. Shaoxing Huangjiu is produced in Zhejiang province and remains the oldest and most representative Chinese rice wine. During storage, Shaoxing Huangjiu is susceptible to environmental disturbance and produces colloidal haze to result in turbidity. In this study, the main composition and source of colloidal haze protein in Shaoxing Huangjiu were analyzed by two‐dimensional electrophoresis and matrix‐assisted laser ionization time‐of‐flight tandem mass spectrometry (MALDI‐TOF/TOF MS). The results showed that the proteins in colloidal haze mainly consisted of oat protein b1, oat‐like protein, di‐amylase inhibitor, pathogenesis‐related protein, pathogenesis‐related protein‐4, chitinase II derived from wheat and oat‐like protein, and beta‐amylase derived from rice. The amino acid composition and secondary structure of haze protein and supernatant protein in Huangjiu were further explored by high‐performance liquid chromatography and Fourier transform infrared spectroscopy. The study has broadened knowledge of the main composition and source of colloidal haze protein in Shaoxing Huangjiu. The corresponding results indicated that the amino acid composition from colloidal haze had the main characteristics of high hydrophobicity and low water solubility., In this study, the main composition and source of colloidal haze protein in Chinese rice wine (Shaoxing Huangjiu) were analyzed by two‐dimensional electrophoresis and matrix‐assisted laser ionization time‐of‐flight tandem mass spectrometry (MALDI‐TOF/TOF MS). Meanwhile, the amino acid composition and secondary structure of haze protein and supernatant protein in Huangjiu were further explored by high‐performance liquid chromatography and Fourier transform infrared spectroscopy.

By means of ex vivo tissue deuterium-labeling using the stable isotope-labeled precursor [6,6,6-2H3]-(±)-mevalonolactone and microvinification experiments, we were able to show for the first time that the three sesquiterpene hydrocarbons, guaiazulene, δ-selinene, and selina-3,7(11)-diene, in Lemberger red wines do not originate from acid-catalyzed cyclization of yeast-derived farnesol and nerolidol. The three aforementioned sesquiterpene hydrocarbons could be unambiguously identified as grape-derived secondary metabolites and can therefore be considered as variety-specific marker compounds. The analysis of sesquiterpene hydrocarbons in red wine samples was performed by solid-phase extraction-headspace solid-phase microextraction-comprehensive two-dimensional gas chromatography-time of flight-mass spectrometry. The developed methodology paves the way for an analytical verification of grape variety labeling in wine authenticity control.

We have developed a novel yet efficient method for the multi residue analysis of organic compounds of diverse polarities in water using Liquid Chromatography-Time of Flight mass spectrometry (LC-MS-TOF) equipped with a jet stream Electrospray ionization (ESI) source. Use of three different fragmentor voltages (low, medium and high) enabled the qualitative and quantitative analysis of a diverse range of targeted organic compounds in environmental waters. No prior optimization of compounds being quantified was required, the limiting factors were ionization behaviour of compounds under conditions of ESI and good chromatography. Same data file could be subjected to repeated post-run data analysis to figure out the presence of non-targeted compounds, including designer drugs if any. The technique has been illustrated with reference to a group of pesticides having diverse chromatographic and ionization behaviours. The optimized Solid Phase Extraction (SPE) followed by method validation yielded a robust yet simple quantitative method for a group of fourteen pesticides. We were able to achieve quantitation at 10 ng/L or lower depending upon ionization behaviour of substrates against the usual regulatory requirement of 1000 ng/L. The method was used for targeted and non-targeted detection of pesticides in Nueces estuary waters, TX, USA, and several untargeted pesticides, pharmaceuticals and personal care products were identified.

A method for simultaneous determination of multi-class antibiotics and steroid hormone analysis in faeces of livestock and poultry was developed using liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QTOF MS). An in-house database was built for 156 detected drugs using Personal Compound Database Library software (PCDL) including compound name, monoisotopic mass, chemical formula, RT, chemical structure and three CID MS/MS spectra. The linearity result showed that all the drugs exhibited good linearity with determination coefficients (R2) higher than 0.99. The drug recoveries and their RSDs for all three faeces samples (pig, cattle and chicken) were tested and 81, 96 and 92 drugs were chosen for analysis in pig, cattle and chicken faeces, respectively. Further validation showed that 73 veterinary drugs in all three kinds of faeces samples can be quantified in one analytical run. This work shows that qualitative and quantitative analysis using LC-QTOF MS represents a simple, sensitive, low-cost and high-throughput methodology in routine laboratory analyses.

The study investigated the zearalenone (ZEA) neutralization process as a consequence of metabolization and binding process by the probiotic bacterial strain Lactobacillus paracasei using high performance liquid chromatography (HPLC). In order to determine the nature of the binding process the kinetic and spectroscopic approach were used. Moreover, the influence of ZEA on L. paracasei metabolism was examined by the determination of the proteome profile of cells and the profile of volatile compounds (VOCs) produced by bacteria cells. For this purpose the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS) and headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry (HS-SPME/GC-MS) techniques were used. The obtained results indicate that in the mechanism of ZEA neutralization both - metabolization/biotransformation and binding/biosorption processes are involved. Furthermore, the biotransformation of ZEA to both α- and β-ZOL with a predominance of β-ZOL by lactic acid bacteria strain was recorded. The results suggest that the tested microorganism can be used as a potential detoxification agent for grain and feed.

Background: Xiexin Tang (XXT) is a classic Traditional Chinese Medicine (TCM) formula that has been used in herbal clinics for more than 1800 years. Recently, many studies have investigated the pharmacological effects and chemical composition of XXT. However, there is little information about systematic studies on the material basis of its efficacy. In the present study, the serum pharmacochemistry technique and HPLC-DAD-Q-TOF/MS were performed to screen and analyze the multiple absorbed bioactive components and metabolites of orally dosed XXT in rat serum. Methods: Bio-samples and herbal extracts were analyzed and detected by HPLC-DAD-Q-TOF/MS. Upon comparison of the chromatograms of the single-constituent decoctions with that of the XXT formulation, the peak quantity and peak intensity of the formulated decoction showed some variation from those of the single-constituent decoctions. Results: Twenty-one serum-adsorbed constituents were identified after intragastric administration of herbal extracts, of which 8 originated from Rhei Radix et Rhizoma (RRR), 5 from Coptidis Rhizoma (CR), and 8 from Scutellariae Radix (SR). The results showed that the main adsorbed constituents in the serum were anthraquinones, anthrones, chromones, and butyrophenones, alkaloids, and flavonoids. Conclusion: The results demonstrate that an effective and reliable analytical method is set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of XXT.

This powerful mass spectrometric technique was used to investigate four profen drugs which are widely used as non-steroidal anti-inflammatory drugs for treating pain, fever and inflammation: Ibuprofen (M = 206), Flurbiprofen (M = 244), Naproxen (M = 230) and Ketoprofen (M = 254). The DART ion source was operated in positive ion mode with helium as the ionizing medium heated to 250°C. A solution containing a mixture of poly (ethylene glycol) standards PEG 600 and PEG 200 was used for mass calibration. A standard solution of each pure standard was manually introduced by using a small glass rod. The high resolution mass spectra of Ibuprofen, Flurbiprofen, Naproxen and Ketoprofen showed the presence of an intense protonated molecular ion [M + H]+ at 207.13860, 245.09776, 231.10632 and 255.09966 Da, respectively. Moreover, a non-protonated molecular ion M+ was also observed except for Ketoprofen. On the other hand, an intense adduct ion [M + H2O]+ was also present in the four mass spectra. Since these profens are 2-arylpropionic acid derivatives they have a known tendency to form dimers; indeed, an intense protonated ion corresponding to this dimer [2M + H]+ was present in the spectrum of Ibuprofen, Flurbiprofen, Naproxen and Ketoprofen at 413.27102, 489.19944, 461.19266 and 509.19662 Da, respectively. The presence of profens as active ingredients was then investigated in various pharmaceutical tablets collected from the local market. A small piece of each solid tablet was submitted to the DART ion source without any sample preparation. The obtained mass spectrum showed the characteristic peaks corresponding to each profen as active principle, as well as the other ingredients of the tablet.

A qualitative and quantitative method based on ultra-performance liquid chromatography (UPLC) and photodiode array (PDA) and electrospray ionization–quadrupole time-of-flight mass spectrometry (ESI...

Objective: The aim of this study is to investigate the pharmacokinetics of benzoic acid, 4- [[(2-hydroxyethyl)amino]carbonyl], methyl ester in rats after intravenous and oral administrations at doses of 3 mL/kg. Methods: A rapid, high selective ultra-high performance liquid chromatographic electrospray quadrupole- time of flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) method was applied to investigate the pharmacokinetics of benzoic acid, 4-[[(2-hydroxyethyl)amino]carbonyl]-, methyl ester with p-coumaric acid as internal standard (IS) in rats after intravenously and orally dosed. Results: The pharmacokinetic data of benzoic acid, 4-[[(2-hydroxyethyl)amino]carbonyl]-, methyl ester was analyzed in the two-compartment open model. The main pharmacokinetic parameters were, respectively, 36.474 μg·h/mL, 12.59 μg·h/mL (AUC0→∞), and T1/2α was 0.14 h, 0.359 h; T1/2β was 3.046 h, 5.646 h after intravenous and oral administrations. Conclusion: Benzoic acid, 4-[[(2-hydroxyethyl)amino] carbonyl]-, methyl ester was rapidly distributed in rat’s plasma with the absolute bioavailability of 34.5%.