Liquid Chromatography quadrupole-Orbitrap Mass Spectrometry Research Articles

Identification of post-mortem product of zolpidem degradation by hemoglobin via the Fenton reaction.

Zolpidem, N,N-dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide, is a hypnotic agent widely used in clinical practice but is detected in many clinical cases of fatal intoxication and suicide. In forensic toxicology, the precise determination of zolpidem concentration in blood is a must to provide concrete evidence of death by zolpidem poisoning. However, the concentrations of zolpidem in blood at autopsy often differ from those at the estimated time of death. In the present study, we found that zolpidem was degraded by hemoglobin (Hb) via the Fenton reaction at various temperatures. The mechanism underlying zolpidem degradation involved the oxidation of its linker moiety. The MS and MS/MS spectra obtained by liquid chromatography quadrupole-Orbitrap mass spectrometry (LC-Q-Orbitrap-MS) showed the formation of 2-hydroxy-N,N-dimethyl-2-(6-methyl-2-(p-tolyl)imidazo[1,2-a]pyridin-3-yl)acetamide (2-OH ZOL) in Hb/H2O2 solution incubated with zolpidem and in the blood of several individuals who died from ingestion of zolpidem. These results suggest that 2-OH ZOL is the post-mortem product of zolpidem degradation by Hb via the Fenton reaction.

Mechanism of n-butanol fraction of Wenxia Formula combining with gefitinib in treating non-small cell lung cancer based on network pharmacology and in vitro experiment

This study combined network pharmacology, molecular docking, and in vitro experiments to explore the potential mechanism of the active components of the n-butanol fraction of Wenxia Formula(NWXF) combined with gefitinib(GEF) in treating non-small cell lung cancer(NSCLC). Ultra-performance liquid chromatography-quadrupole Orbitrap mass spectrometry(UPLC-Q-Orbitrap MS) was employed to detect the main chemical components of NWXF. The active components of NWXF were retrieved from SwissADME, and the candidate targets of these active components were retrieved from SwissTargetPrediction. Online Mendelian Inheritance in Man(OMIM) and GeneCards were searched for the targets of NSCLC. Cytoscape 3.9.0 and STRING were employed to build the protein-protein interaction(PPI) network with the common targets shared by NWXF and NSCLC. Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment were performed in DAVID to predict the potential mechanisms. Finally, molecular docking between the main active ingredients and key targets was conducted in SYBYL-X 2.0. The methyl thiazolyl tetrazolium(MTT) assay was employed to evaluate the inhibitory effects of NWXF and/or GEF on the proliferation of human non-small cell lung cancer cells(A549 and PC-9). Additionally, the impact of NWXF on human embryonic lung fibroblast cells(MRC-5) was assessed. The effectiveness of the drug combination was evaluated based on the Q value. The terminal-deoxynucleoitidyl transferase mediated nick-end labeling(TUNEL) assay was employed to examine the apoptosis of A549 and PC-9 cells treated with NWXF and/or GEF. Quantitative real-time PCR(qRT-PCR) was employed to measure the mRNA levels of epidermal growth factor receptor(EGFR), c-Jun N-terminal kinase(JNK), and Bcl2-associated X protein(Bax) in the A549 and PC-9 cells treated with NWXF and/or GEF. Western blot was employed to determine the protein levels of EGFR, p-EGFR, JNK, p-JNK, and Bax in the A549 and PC-9 cells treated with NWXF and/or GEF. A total of 77 active components, 488 potential targets, and 49 key targets involved in the treatment of NSCLC with NWXF were predicted. The results of GO annotation showed that NWXF may treat NSCLC by regulating the biological processes such as cell proliferation, apoptosis, and protein phosphorylation. KEGG enrichment revealed that the key targets of NWXF in treating NSCLC were enriched in the mitogen-activated protein kinase(MAPK), phosphatidylinositol 3-kinase(PI3K)-protein kinase B(AKT), hypoxia-inducible factor-1(HIF-1), and microRNA-related signaling pathways. Molecular docking results showed that 91.9% of the docking scores were greater than 5, indicating the strong binding capability between main active components and key targets. The cell experiments demonstrated that NWXF combined with GEF synergistically inhibited the proliferation, promoted the apoptosis, decreased p-EGFR/EGFR and p-JNK/JNK values, down-regulated the mRNA levels of EGFR and JNK, and up-regulated the mRNA and protein levels of Bax in A549 and PC-9 cells. In conclusion, NWXF combined with GEF can regulate the EGFR/JNK pathway to promote the apoptosis of NSCLC cells, thus treating NSCLC.

Identification of post-mortem paliperidone metabolite in human blood by LC-Q-Orbitrap-MS.

Paliperidone is a widely used antipsychotic agent detected in many fatal intoxications and suicide cases. In forensic toxicology, the accurate determination of blood paliperidone concentrations is required to prove death by paliperidone poisoning. However, the lethal concentration of paliperidone in blood at autopsy differs from that at the time of death. In this study, we found that paliperidone was decomposed by hemoglobin (Hb) through the Fenton reaction in a temperature-dependent fashion. The mechanism underlying paliperidone decomposition involves the cleavage of its C-N bond linker moiety. The mass spectra obtained by liquid chromatography quadrupole orbitrap mass spectrometry (LC-Q-Orbitrap-MS) revealed the formation of 6-fluoro-3-(4-piperidinyl)benzisoxazole (PM1) in Hb/H2O2 solution incubated with paliperidone, as well as in the blood of individuals who died from intentional ingestion of paliperidone. These results suggest that PM1 is the only metabolite produced from paliperidone as a result of temperature-dependent, post-mortem changes induced by Hb via the Fenton reaction, and may be useful as a biomarker to correct for the concentration of paliperidone in blood at the time of death in clinical cases.

Liquid chromatography-quadrupole orbitrap and liquid chromatography-tandem mass spectrometry system for rapid identification and quantitation of thirty nonsteroidal anti-inflammatory drugs and acetaminophen in illegal products.

As the public interest in healthcare increases, illegal dietary supplements, foods, and drugs containing unauthorized pharmaceutical ingredients, including nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen, have been identified. Excessive and unintentional consumption is toxic to the gastrointestinal tract, kidneys, and liver; therefore, these pharmaceuticals must be monitored using analytical methods. A rapid and reliable analysis system involving liquid chromatography-quadrupole orbitrap mass spectrometry (LC-Q-Orbitrap/MS) and liquid chromatography-tandem mass spectrometry (LC/MS/MS) was established and validated to identify and quantify 30 NSAIDs and acetaminophen. In addition, we obtained the MS2 spectrum for each component with the proposed structure of the fragment ions. The analytical method was applied to 505 samples of illicitly distributed dietary supplements, foods, and pharmaceuticals. Non-steroidal analgesics were detected in 126 samples. Carbamazepine (42.9%) and diclofenac (30.2%) were the most detected components in the samples; other pharmaceutical adulterants were also detected in some cases. Additionally, we present the identification of an unknown component, dexamethasone (799 μg/g), using LC-Q-Orbitrap/MS in a sample containing the unknown component with meloxicam (15.4mg/g). The developed analysis system, consisting of qualitative analysis using LC-Q-Orbitrap/MS and quantitative analysis using LC/MS/MS, can rapidly and accurately identify and quantify NSAIDs and acetaminophen while also identifying non-analytical components.

Screening and quantification of 146 veterinary drug residues in beef and chicken using QuEChERS combined with high performance liquid chromatography-quadrupole orbitrap mass spectrometry

This work aimed to develop an integrated high-throughput screening and quantification for multi-class veterinary drug residues by HPLC-Q-Orbitrap mass spectrometry. A qualitative screening mass database of 171 veterinary drugs was created using full scanning mode, which improved the screening accuracy and scope. Beef and chicken samples were chosen to validate the quantification method at three spiked concentration levels. The quantification method of 146 veterinary drug residues was developed. After enzymatic hydrolysis, beef and chicken samples were treated using optimized QuEChERS. The calibration curves showed good linearities with correlation coefficients of 0.9921–0.9994. The recovery rates were within 52.1–138.2 % with relative standard deviations 0.4–17.7 %. The limits of detection and limits of quantification were in the range of 0.15–3.03 μg/kg and 0.5–10 μg/kg, respectively. The proposed method was demonstrated to be reliable for the simultaneous analysis of multi-class veterinary drugs. It is of significance to expand the screening scope and quantitative analysis efficiency.

Rapid identification and quantitative determination of chemical compositions in Buyang Huanwu decoction based on HPLC-Q-Exactive mass spectrometry.

To establish an analytical method for rapid identification of chemical compositions and quantitative determination of major compositions in Buyang Huanwu decoction (BYHWD) based on high performance liquid chromatography-quadrupole orbitrap mass spectrometry (HPLC-Q-Exactive MS) and high performance liquid chromatography-ultraviolet detection (HPLC-UV). The mass spectrometry information was collected in Full MS/dd-MS 2 negative ion mode with HPLC-Q-Exactive MS system; the chemical compositions of BYHWD were subsequently annotated with Compound Discoverer 3.0 software and a self-built in-house compound library. Eight major compositions (paeoniflorin, gallic acid, hydroxysafflor yellow A, ferulic acid, calycosin-7-glucoside, ononin, calycosin, formononetin) were picked out and their contents were quantitatively determined with HPLC-UV analysis. A total of 178 compounds in BYHWD were tentatively identified. The results of HPLC-UV quantitative analysis showed that 8 compositions had a good linear relationship in their respective concentration range ( R 2≥0.9990), the relative standard deviations (RSD) of precision and stability were all less than 15%, and the recovery rate RSD was between 1.6% and 2.4%. The method established in this study can realize the rapid identification and accurate quantification of the major compositions in BYHWD. Paeoniflorin, hydroxysafflor yellow A and gallic acid may be used as quality control markers.

Bioassay and UPLC-Q-Orbitrap-MS/MS guided isolation of polycyclic polyprenylated acylphloroglucinols from St. John's wort and their neuroprotective activity

St. John’s wort ( Hypericum perforatum L.) is a popular dietary supplement ingredient used for the treatment of mild-to-moderate depression in the United States and Germany. Reported studies mainly focused on the biological evaluation and mechanism study of its crude extracts or two main components (namely, hypericin and hyperforin). However, it is unclear whether other phytochemicals including polycyclic polyprenylated acylphloroglucinols (PPAPs) contributed to the neuroprotective effects of H. perforatum. Here, bioassay and ultra performance liquid chromatography–quadrupole orbitrap mass spectrometry (UPLC-Q-Orbitrap-MS/MS) guided isolation were applied to discover bioactive PPAPs from the crude extracts of H. perforatum. A new PPAP, named hyperforen A ( 2 ), along with nine known PPAPs ( 1 and 3 – 10 ), were identified from an ethyl acetate extract of H. perforatum . To the best of our knowledge, compound 2 represents the first PPAP with an unprecedented bicyclo[7.3.0]dodecane core. The chemical structures of the isolates were elucidated by extensive spectroscopic analysis and electronic circular dichroism calculations. Moreover, compounds 1 – 3 , 6 , and 10 (10 μM) exhibited significant neuroprotective effects against corticosterone-induced injury in PC12 cells. Fingings from the current study suggest that bioactive PPAPs from H. perforatum are promising compouds for the management of depression.

Untargeted metabolomic study of acute exacerbation of pediatric asthma via HPLC-Q-Orbitrap-MS

Acute exacerbation of pediatric asthma (AEPA) has always been one of the most common reasons for children to visit the emergency department, whereas unified diagnostic criteria in the clinic are lacking. The purpose of this study was to determine potential biomarkers, and provide a basis for predictive and diagnostics AEPA. Urine samples were collected from 40 pediatric patients, including 19 patients with AEPA (PA) and 21 healthy controls (HCs). The samples were analyzed by high-performance liquid chromatography-quadrupole orbitrap mass spectrometry (HPLC-Q-Orbitrap-MS), and the data were statistically analyzed by principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Differential metabolites were selected by VIP (variable importance for the projection) > 1, and a p value ≤ 0.05 was used as the standard. The corresponding metabolic pathways of differential metabolites were subjected to analysis by the KEGG database, and further analysis and characterization of differential metabolites were conducted through the HMDB database. A total of 26 potential biomarkers were selected, of which 17 were found to be associated with respiratory diseases. Nine metabolites with obvious fluctuations in patients with AEPA, such as 13-L-hydroperoxylinoleic acid, gentisate aldehyde, L-3-phenyllactic acid, hydrocinnamic acid, and gentisic acid, could be used as potential biomarkers to further explore the prediction and diagnosis of AEPA for the first time. The contents of 3 potential biomarkers showed a positive correlation. Abnormalities in seven metabolic pathways, such as phenylalanine metabolism, tyrosine metabolism and beta-alanine metabolism, are also related to AEPA. This study further confirmed the reliability of this method to detect differences in urine metabolites of patients with AEPA. By monitoring the content of these 26 potential biomarkers and their related metabolic pathways, it provides a basis for further effective prediction and diagnosis of AEPA to avoid further development of this disease.

Identification and characterization of higenamine metabolites in human urine by quadrupole-orbitrap LC-MS/MS for doping control

Higenamine is an alkaloid found in aconite, Annona squamosa, nanzhu (sacred bamboo), and other plants. It can be used to treat coughing, asthma, heart failure, and erectile dysfunction as well as aid in weight loss. It is also a banned substance in and out of competition as defined by the World Anti-Doping Agency (WADA). In this work, higenamine metabolic profiles were investigated in detail. Two healthy volunteers (one male and one female) took a higenamine tablet (5 mg), and urine samples were collected for two weeks. Solid-phase extraction (SPE) without enzymatic hydrolysis was used to clean the urine samples, and the urine extracts were then analyzed by liquid chromatography–quadrupole-orbitrap mass spectrometry (quadrupole-orbitrap LC–MS/MS) with accurate mass measurements. Higenamine and 32 metabolites were detected: 6 methylated, 10 sulfated and 16 glucuronidated metabolites. The chemical structures were elucidated by their fragmentation patterns, and accurate molecular formula determination was obtained for these newly reported metabolites. Three metabolic pathways containing methylation, glucuronidation, sulfation, and combinations of these were provided with methylation as the main metabolic pathway. The post-dose detection windows within urine of all 32 metabolites were compared with that of the parent drug, and a new potential biomarker (M7) was suggested for higenamine misuse. All urine samples were processed by two sample preparation methods: the dilute-and-shoot (DS) procedure and acid hydrolysis followed by SPE, and the time periods for a higenamine positive trails of two methods were compared. Although the DS method used to process the urine samples of athletes in the most of WADA-accredited laboratories to detect only free higenamine, acid hydrolysis followed by SPE is preferable and offers routine analysis to avoid false-negative results.

Metabolomic Study of Acute Exacerbation of Pediatric Asthma Via HPLC-Q-Orbitrap-MS

Acute exacerbation of pediatric asthma (AEPA) has always been one of the most common reasons for children to visit the emergency department, whereas unified diagnostic criteria in the clinic are lacking. The purpose of this study was to determine potential biomarkers, and provide a basis for predictive and diagnostics AEPA. Urine samples were collected from 40 pediatric patients, including 19 patients with AEPA (PA) and 21 healthy controls (HCs). The samples were analyzed by high-performance liquid chromatography-quadrupole orbitrap mass spectrometry (HPLC-Q-Orbitrap-MS), and the data were statistically analyzed by principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Differential metabolites were selected by VIP (variable importance for the projection) > 1, and a p value ≤ 0.05 was used as the standard. The corresponding metabolic pathways of differential metabolites were subjected to analysis by the KEGG database, and further analysis and characterization of differential metabolites were conducted through the HMDB database. A total of 26 potential biomarkers were selected, of which 17 were found to be associated with respiratory diseases. Nine metabolites with obvious fluctuations in patients with AEPA, such as 13-L-hydroperoxylinoleic acid, gentisate aldehyde, L-3-phenyllactic acid, hydrocinnamic acid, and gentisic acid, could be used as potential biomarkers to further explore the prediction and diagnosis of AEPA for the first time. The contents of 3 potential biomarkers showed a positive correlation. Abnormalities in seven metabolic pathways, such as phenylalanine metabolism, tyrosine metabolism and beta-alanine metabolism, are also related to AEPA. This study further confirmed the reliability of this method to detect differences in urine metabolites of patients with AEPA. By monitoring the content of these 26 potential biomarkers and their related metabolic pathways, it provides a basis for further effective prediction and diagnosis of AEPA to avoid further development of this disease.

Target Quantification and Semi-Target Screening of Undesirable Substances in Pear Juices Using Ultra-High-Performance Liquid Chromatography-Quadrupole Orbitrap Mass Spectrometry.

Fruit juices are common products in modern diets due to the supply of vegetal nutrients combined with its tastiness. Nevertheless, potential contaminants, such as mycotoxins and pesticides, can be present in commercial products due to a potential carry-over. Therefore, the aim of this study was to investigate for the first time the presence of 14 Fusarium mycotoxins using a quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction followed by an ultra-high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry in 21 pear juice samples from Italian markets. Up to nine different mycotoxins were detected, particularly an extensive presence of zearalenone (67%, n = 21, mean value = 0.88 ng/mL). Emerging Fusarium mycotoxins enniatins B, B1, A, and A1 were also detected. Additionally, 77 pesticide residues were tentatively identified through a retrospective analysis based on a mass spectral library. The prevalent presence of some non-approved pesticides, such as ethoxyquin (64%, n = 21) and triazophos (55%, n = 21), must be highlighted. The results obtained indicate an extensive contamination of marketed pear juice with undesirable compounds, and they should be taken into consideration when performing risk assessment studies.

Simultaneous determination of ten aminoglycoside antibiotics in aquatic feeds by high-performance liquid chromatography quadrupole-orbitrap mass spectrometry with pass-through cleanup.

A simple and sensitive method has been established based on pass-through cleanup and high-performance liquid chromatography quadrupole-orbitrap mass spectrometry (HPLC-Q/Orbitrap MS) for the simultaneous determination of ten aminoglycosides (AGs) in aquatic feeds. The extraction solution and cleanup procedure had been optimized, and good sensitivity, accuracy, and precision were obtained. The calibration curves of AGs were linearity (R2 > 0.99) in the range of 2.0 to 200 μg/L (or 5.0 to 500 μg/L). The limits of detection of AGs were between 10 and 25 μg/kg. The recoveries of AGs ranged from 74.9% to 94.3%, and the intraday and interday relative standard deviations were less than 15%. Finally, this method was successfully applied to determine ten AGs in 30 aquatic feed samples. It might be the first time to use pass-through cleanup approach combined with HPLC-Q/Orbitrap MS method for AGs determination in aquatic feed samples.

Liquid chromatography quadrupole-Orbitrap mass spectrometry for the simultaneous analysis of advanced glycation end products and protein-derived cross-links in food and biological matrices

Advanced glycation end products (AGEs) and protein cross-links have been extensively investigated in both food and biomedical fields over the past years. Although there are a few chromatographic and immunological methods for the analysis of selected AGEs, there is no method available for comprehensive simultaneous analysis of major AGEs found in processed foods and biological samples. In the present study, we have reported a validated UHPLC-MS/MS method for simultaneous identification and quantification of 15 different AGEs, furosine (an indicator of Amadori products), 2 protein-derived cross-links (lanthionine and lysinoalanine) and 2 amino acids (Lys and Arg). The analytes were separated on a reversed phase C-18 column and quantified accurately based on the isotope dilution method, where 9 stable isotope-labelled internal standards were used to quantify 20 different analytes using an Orbitrap mass analyzer. The method showed acceptable linearity, accuracy and precision. The LOD and LOQ values in plasma were in the range of 0.30–19.02 and 0.87–57.06 ng/mL, respectively. The recovery values at the three spiked levels were in the range of 71–110%, with some exceptions. The intraday and interday precision were in the range of 1.5–13.2%, however, quantification of N-ɛ-(carboxymethyl)lysine accompanied slightly higher interday precision (30.7%). The applicability of the method was successfully assessed by analyzing AGEs and protein cross-links in six different complex matrices including Ultra-High Temperature (UHT) processed milk, roasted chicken breast meat, roasted chicken skin, roasted pork liver, bovine plasma and perfusion liquid.

Structure Elucidation and Toxicity Analysis of the Degradation Products of Deoxynivalenol by Gaseous Ozone.

Fusarium Head Blight (FHB) or scab is a fungal disease of cereal grains. Wheat scab affects the yield and quality of wheat and produces mycotoxins such as deoxynivalenol (DON), which can seriously threaten human and animal health. In this study, gaseous ozone was used to degrade DON in wheat scab and the degradation products of ozonolysis were analyzed by ultra-performance liquid chromatography quadrupole-orbitrap mass spectrometry (UHPLC Q-Orbitrap). Toxicology analyses of the degradation products were also studied using structure-activity relationships. Ozone (8 mg L−1 concentration) was applied to 2 μg mL−1 of DON in ultrapure water, resulted in 95.68% degradation within 15 s. Ten ozonized products of DON in ultrapure water were analyzed and six main products (C15H18O7, C15H18O9, C15H22O9, C15H20O10, C15H18O8, and C15H20O9) were analyzed at varying concentrations of ozone and DON. Structural formulae were assigned to fragmentation products generated by MS2 and Mass Frontier® software. According to structure-activity relationship studies, the toxicities of the ozonized products were significantly decreased due to de-epoxidation and the attack of ozone at the C9-10 double bond in DON. Based on the results of the study above, we can find that gaseous ozone is an efficient and safe technology to degrade DON, and these results may provide a theoretical basis for the practical research of detoxifying DON in scabby wheat and other grains.

Multiclass screening of >200 pharmaceutical and other residues in aquatic foods by ultrahigh-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry.

A quick screening method of more than 200 pharmaceutical and other residues in aquatic foods based on ultrahigh-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (UHPLC-Q/Orbitrap MS) was established. In this method, after the addition of 200μL of 1M EDTA-Na2, 2g of each sample homogenate was extracted successively with 10mL of acetonitrile and 10mL of ethyl acetate. The extracts were combined, dried under nitrogen flow, and redissolved in 0.1% formic acid in acetonitrile/water (4:6, v/v) for analysis. The prepared samples were analyzed by UHPLC- Q/Orbitrap MS system in Full MS/ddMS2 (full-scan data-dependent MS/MS) mode. Compound identification was performed through comparison of the sample data with the database for standard chemicals, including the retention time, precursor ion, product ions, and isotope pattern for all 206 compounds. Five different aquatic food matrices (carp, shrimp, crab, eel, and mussel) spiked with the analytes at 1, 10, and 50ng/g were evaluated to assess recoveries, precision, matrix effects, stability, and detection limits using the method. UHPLC analyses required 25min, and 178-200 analytes met identification criteria at 50ng/g depending on the matrix. Furthermore, practical application of this method for real samples displayed strong screening capability. Graphical abstract A quick screening method of >200 pharmaceutical and other residues in aquatic foods based on ultrahighperformance liquid chromatography-quadrupole-Orbitrap mass spectrometer was established. Fivedifferent aquatic food matrices, including carp, shrimp, crab, eel and mussel, were studied to evaluatescreen limit at 1, 10 and 50 μg·kg-1 level. Results suggest the high reliability, high time-efficiency and goodsimplicity of the method.

Development and Validation of LC–MS/MS and LC-Q-Orbitrap/MS Methods for Determination of Glyphosate in Vaccines

We developed and validated a simple and an accurate method for determination and quantification of glyphosate residue in vaccines. Vaccines were centrifuged in the first step of sample preparation to eliminate matrix effects. The sample was washed with a mixture of dichloromethane and chloroform, and was directly analysed without derivatisation. The extract was injected into a liquid chromatography tandem mass spectrometry (LC–MS/MS) system and liquid chromatography quadrupole-orbitrap mass spectrometry (LC-Q-Orbitrap/MS) with a Hypercarb column. The methods were validated through a series of assessments including specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, precision and accuracy, recovery, and stability. In LC–MS/MS, LOD and LOQ of glyphosate in DPT and pneumococcal vaccines were 0.078 and 0.258 ng mL−1, whereas MMR was 0.156 and 0.515 ng mL−1. In Q-Orbitrap/MS, LOD and LOQ of glyphosate in DPT and pneumococcal vaccines were 2.425 and 8.803 ng mL−1, whereas MMR was 4.850 and 16.166 ng mL−1. The linear correlation coefficients (r 2) were higher than 0.999. Relative standard deviation (RSD) was 0.9–11.7% for both intra-day and inter-day precisions. Accuracy was evaluated to be in the range of 86.3–110.4% both for intra-day and for inter-day. Mean recoveries of three different fortification levels were within 93.1–108.3% for DPT and pneumococcal vaccines and 71.1–73.4% for MMR vaccine. The RSD of stability of spiked samples was within 8%.

A first step in the quest for the active constituents in Filipendula ulmaria (meadowsweet): comprehensive secondary metabolite identification by liquid chromatography-quadrupole orbitrap mass spectrometry

A first step in the quest for the active constituents in Filipendula ulmaria (meadowsweet): comprehensive secondary metabolite identification by liquid chromatography-quadrupole orbitrap mass spectrometry

An efficient, sensitive and accurate method for the detection of astragaloside IV in Chinese functional spirit by ultra-performance liquid chromatography–quadrupole-orbitrap mass spectrometry

Mainly consisting of Chinese white spirit and traditional Chinese medicine, Chinese functional spirit is a popular health food in China due to its healthy effects, such as resisting fatigue and enhancing immunity.

In Vitro and in Vivo Metabolism of Verproside in Rats

Verproside, a catalpol derivative iridoid glycoside isolated from Pseudolysimachion rotundum var. subintegrum, is a biologically active compound with anti-inflammatory, antinociceptic, antioxidant, and anti-asthmatic properties. Twenty-one metabolites were identified in bile and urine samples obtained after intravenous administration of verproside in rats using liquid chromatography-quadrupole Orbitrap mass spectrometry. Verproside was metabolized by O-methylation, glucuronidation, sulfation, and hydrolysis to verproside glucuronides (M1 and M2), verproside sulfates (M3 and M4), picroside II (M5), M5 glucuronide (M7), M5 sulfate (M9), isovanilloylcatalpol (M6), M6 glucuronide (M8), M6 sulfate (M10), 3,4-dihydroxybenzoic acid (M11), M11 glucuronide (M12), M11 sulfates (M13 and M14), 3-methyoxy-4-hydroxybenzoic acid (M15), M15 glucuronides (M17 and M18), M15 sulfate (M20), 3-hydroxy-4-methoxybenzoic acid (M16), M16 glucuronide (M19), and M16 sulfate (M21). Incubation of verproside with rat hepatocytes resulted in thirteen metabolites (M1–M11, M13, and M14). Verproside sulfate, M4 was a major metabolite in rat hepatocytes. After intravenous administration of verproside, the drug was recovered in bile (0.77% of dose) and urine (4.48% of dose), and O-methylation of verproside to picroside II (M5) and isovanilloylcatalpol (M6) followed by glucuronidation and sulfation was identified as major metabolic pathways compared to glucuronidation and sulfation of verproside in rats.