High-performance Liquid Chromatography Tandem Quadrupole Research Articles

Analysis of 15 bile acids in human plasma based on C18 functionalized magnetic organic polymer nanocomposite coupled with liquid chromatography-tandem mass spectrometry

Because of the “enterohepatic circulation” of bile acid, liver damage can be reflected by monitoring the content of bile acid in the serum of the organism. To monitor the concentration of 15 bile acids in plasma samples, a new technique of PRiME (process, ruggedness, improvement, matrix effect, ease of use) pass-through cleanup procedure combined with high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS/MS) was developed. The sorbent used in the PRiME pass-through cleanup procedure is a new type of magnetic organic resin composite nano-material modified by C18 (C18-PS-DVB-GMA-Fe3O4), which has high cleanup efficiency of plasma samples. It also shows good performance in the separation and analysis of 15 kinds of bile acids. Under the optimal conditions, the results show higher cleanup efficiency of C18-PS-DVB-GMA-Fe3O4 with recoveries in the range of 82.1–115 %. The limit of quantitative (LOQs) of 15 bile acids were in the range of 0.033 µg/L-0.19 µg/L, and the RSD values of 15 bile acids were in the range of 3.00–11.9 %. Validation results on linearity, specificity, accuracy and precision, as well as on the application to analysis of 15 bile acids in 100 human plasma samples demonstrate the applicability to clinical studies.

Components research on Tetrastigma hemsleyanum Diels et Gilg: Identification and effect of drying methods on the content of ten main constituents by targeting metabolomics method

Tetrastigma hemsleyanum Diels et Gilg (TH) is one of the new eight Genuine Medicinal Materials of Zhejiang. It has extensive biological activities, such as anti-inflammatory, anti-tumor and analgesic activities, etc. In this study, the chemical components of TH were systematically investigated by ultra high-performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (UPLC/Q-TOF-MS). Based on the MS spectrum, 39 compounds in TH extracts including 14 flavonoids, 10 fatty acids, 5 polyphenols and phenolic acids, 4 terpenes and other compounds were detected and tentatively identified. TH samples were treated under different drying methods (vacuum freeze drying, hot air drying, natural drying, light drying and vacuum drying). Besides, the effect of different drying methods on the content of 10 main chemical constituents in TH extracts including catechin, rutin, kaempferol-3-O-rutinoside and so on was also investigated by targeting metabolomics method with ultra high-performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-MS/MS) assisted by multivariate statistical analysis. Large differences were observed between vacuum drying and vacuum freeze drying with remarkable content changes. The contents of rutin, proanthocyanidin B1 and catechin were the most different among the various drying methods. The systematic identification of chemical constituents is helpful for the further medicinal development and application of TH. The effects of drying methods on the content of TH components were studied, which provided experimental data for the processing, storage and quality control of TH.

Method Validation for Simultaneous Quantification of Some High-risk Pesticides in Surface Water Samples by SPE-LC-MS/MS

ABSTRACT In this paper, a solid phase extraction procedure was developed for the simultaneous extraction of 22 multiclass high-risk pesticides, containing a variety of chemical groups (organophosphate, neonicotinoid, sulfonylurea, strobilurin, triazole, triazine, and acetanilide), from surface water samples. The target analytes extracted on the HLB SPE cartridge, and then eluted with acetonitrile with 5% (v/v) formic acid. The final sample solution was analysed by high-performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC–MS/MS) system. Under optimum conditions, good linearity was obtained for the target pesticides with correlation coefficient greater than 0.99. The limit of quantitation (LOQ) for the 22 pesticides was 0.1 ng/mL. The absolute recoveries of the pesticides from spiked water samples ranged from 70.0% to 121.5%. Relative standard deviations (RSD) for five replicate determinations were below 14.7%. The proposed method has been successfully applied to detect the presence of multiclass pesticides in environmental water samples.

Ultratrace analysis of per- and polyfluoroalkyl substances in drinking water using ice concentration linked with extractive stirrer and high performance liquid chromatography – tandem mass spectrometry

Detection of drinking water contaminants is vital to the protection of human health. One group of contaminants that have recently generated serious concerns over health risks are per- and polyfluoroalkyl substances (PFAS). These compounds are very bio-persistent, leading to their detection in all types of water sources, including drinking water. While analysis of drinking water for PFAS is important, it is currently arduous to detect ultratrace levels of these contaminants. Specifically, current ultratrace PFAS analysis methods are difficult, costly, require large sample volumes, and consume relatively large volumes of organic solvent. In the present work, an analytical method using Ice Concentration Linked with Extractive Stirrer (ICECLES) and high performance liquid chromatography—tandem quadrupole mass spectrometry (HPLC-MS/MS), was developed and validated to provide simple and ultratrace analysis of drinking water for 14 PFAS. The method featured a relatively low sample volume requirement (10 mL), automated extraction, minimal matrix effects, and minimal organic solvent use (i.e., the method requires only 50 µL of methanol per sample). The method produced a wide linear range of 0.5 to 500 ng/L, ultratrace limits of detection (0.05 to 0.3 ng/L), and good accuracy and precision (i.e., 87 to 108% accuracy and ≤19% relative standard deviation as a measure of precision). This method was tested on drinking water samples from across the United States and detected at least one PFAS compound in 52 of the 53 drinking water samples tested. Perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), and perfluoroheptanoic acid (PFHpA) were detected in 89, 96, and 77% of the samples tested with maximum concentrations of 268 ng/L for PFHxA, 213 ng/L for PFOA, and 75.7 ng/L for PFHpA. Additionally, perfluorononanoic acid, perfluorodecanoic acid, and perfluoroheptanoic acid were each detected in at least one drinking water sample at concentrations > 20 ng/L. The availability of the method presented here allows ultratrace detection of PFAS while circumventing many of the disadvantages of current methods.

Magnetic porous carbon derived from Zn/Co metal-organic framework as an adsorbent for extraction and determination of carbamates.

A novel magnetic porous carbon with a high specific surface and magnetization saturation, derived from a Zn/Co-MOF-5, was fabricated by direct carbonization of Zn/Co-MOF-5 without the need of additional carbon precursors under optimum pyrolysis temperature. The material was employed as an adsorbent for magnetic solid-phase extraction of four carbamates from water and tomato samples prior to high-performance liquid chromatography-tandem quadrupole mass spectrometry analysis. Under optimum conditions, the method displayed good linearity (r > 0.9987) within the concentration range 0.05-20ngmL-1 for water samples and 0.1-40ngg-1 for tomato samples. The limits of detection (S/N = 3) for the four carbamate pesticides were in the range 0.0006-0.013ngmL-1 for water samples and 0.001-0.01ngg-1 for tomato samples and satisfactory spiked recoveries in the range 86.1 to 109.1% were obtainedwith the relative standard deviation values from 2.1 to 14.0%. Graphical abstract.

Investigation of the detoxification effect of licorice on Semen Strychni-induced acute toxicity in rats using a HPLC-Q-TOF/MS-based metabolomics approach.

Semen Strychni, a traditional Chinese medicine (TCM), has been widely used to treat paraplegia, facial nerve palsy and myasthenia gravis. However, its clinical application is greatly limited due to its fatal toxicity. To investigate the acute toxicity of Semen Strychni and the detoxification effect of licorice, a high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS) based urinary metabolomics method was developed in this study. After intraperitoneal injection to rats with Semen Strychni extract, the serum biochemical indexes were changed significantly, the liver and kidney showed severe necrosis and edema. Then the poisoned rat model was subsequently used for metabolomics research. Through principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), we finally identified 19 endogenous differential metabolites involved in amino acid metabolism, glycerophospholipid metabolism, tricarboxylic acid (TCA) cycle, oxidative stress and energy metabolism. In addition, 4 exogenous compounds from Semen Strychni (3 prototypes and 1 metabolite) were also identified in the present study. Results showed that the alterations of 23 compounds caused by Semen Strychni were significantly reversed after licorice treatment, which indicated that restoring the endogenous metabolic disorder and accelerating the metabolism of the main toxic components might be the possible detoxification mechanisms of licorice. This study may provide an integral understanding for the acute toxicity of Semen Strychni and the detoxification effect of licorice, thereby contributing to the clinical use of Semen Strychni and licorice.

A Novel Detection Method for Appetite Suppressants Illegally Added into Weight-Loss-Friendly Foods

Weight-loss-friendly foods are often adulterated illegally with appetite suppressants. Therefore, there is an urgent need for effective and reliable methods for the detection of food adulteration. To this end, we have developed a novel detection system called high-performance liquid chromatography-tandem quadrupole time of flight mass spectrometry capable of separation and detection of adulterants as low as 0.03 μg/kg. This method describes all the necessary separation and detection parameters required for the high-throughput detection of simultaneously added multiple suppressants in foods.

Quantitative determination of biogenic amine from Biomphalaria glabrata nervous system by UPLC MS/MS

To establish a method for the quantitative determination of serotonin and dopamine in the nervous system of Biomphalaria glabrata by using ultra high performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC MS/MS) . The B. glabrata nervous system was broken in the pure methanol solution after obtaining it by dissecting with microscope. Then, the supernatant containing the target substance after twice high speed centrifugation was got. The extraction was separated on an ACQUITY UPLC BEH Amide column with Waters TQ-XS series mass spectrometry detector, with ESI source and positive electrospray ionization mode when the machine testing. The detection limit of serotonin was 0.03 ng/ml and the limit of quantification was 0.1 ng/ml. The detection limit of dopamine was 0.05 ng/ml and the limit of quantification was 0.15 ng/ml. The recoveries of serotonin ranged from 90.68% to 94.72% over the range of 1 to 40 ng/ml. The recoveries of dopamine ranged from 91.68% to 96.12% over the range of 1.0 ng/ml to 40 ng/ml. The established UPLC MS/MS method is simple, stable and reproducible. It can be used for the quantitative analysis of serotonin and dopamine in the nervous system of B. glabrata snails.

An integrated high resolution mass spectrometric data acquisition method for rapid screening of saponins in Panax notoginseng (Sanqi)

The aim of this study was to develop a convenient method without pretreatments for nontarget discovery of interested compounds. The segment and exposure strategy, coupled with two mass spectrometer data acquisition methods was firstly proposed for screening the saponins in extract of Panax notoginseng (Sanqi) via high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-QTOF/MS). By gradually removing certain major or moderate interference compounds, the developed segment and exposure strategy could significantly improve the detection efficiency for trace compounds. Moreover, the newly developed five-point screening approach based on a modified mass defect filter strategy and the visual isotopic ion technique was verified to be efficient and reliable in picking out the interested precursor ions. In total, 234 ginsenosides including 67 potential new ones were characterized or tentatively identified from the extract of Sanqi. Particularly, some unusual compounds containing the branched glycosyl group or new substituted acyl groups were firstly reported. The proposed integrated strategy held a strong promise for analyses of the complex mixtures.

Quantification of 2′-deoxy-2′-β-fluoro-4′-azidocytidine in rat and dog plasma using liquid chromatography-quadrupole time-of-flight and liquid chromatography-triple quadrupole mass spectrometry: Application to bioavailability and pharmacokinetic studies

2′-Deoxy-2′-β-fluoro-4′-azidocytidine (FNC) is a novel pyrimidine analog that inhibits not only the replication of the hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV but also the replication of lamivudine-resistant HBV, 4′-azidocytidine or 2′-β-methylcytidine-resistant HCV, and nucleoside reverse-transcriptase inhibitor-resistant HIV variants. The present study was undertaken to evaluate the absolute oral bioavailability of FNC in rats and the pharmacokinetic properties of FNC after intragastric administration of single and multiple doses in rats and dogs. A sensitive high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF MS) method and a reliable high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC/QqQ MS/MS) method were established for the determination of FNC in the rat and dog plasmas, respectively. The sample preparation involved a protein-precipitation method with methanol after the addition of lamivudine as an internal standard. FNC was analyzed by LC using a YMC-Pack Pro C18 column (150mm×4.6mm, 3μm) with methanol (containing 0.3% formic acid): 10mM ammonium acetate (containing 0.3% formic acid, pH 2.8) (35:65, v/v) as the mobile phase. Both mass spectrometers were equipped with an electrospray ionization interface in the positive-ion mode. The linear range was from 2.00 to 2000.00ngmL−1 in rat plasma and 0.50 to 400.00ngmL−1 in dog plasma. The intraday and interday precision were less than 10.55%, and the accuracy was in the range of −5.86 to 5.13%. The mean recoveries were greater than 82.70% and 82.97% for FNC and IS, respectively. The HPLC/Q-TOF MS and HPLC/QqQ MS/MS methods were both successfully applied in the pharmacokinetic studies of FNC in rats and dogs.

Alkaloid profiling of the traditional Chinese medicine Rhizoma corydalis using high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry

Since alkaloids are the major active constituents of Rhizoma corydalis (RC), a convenient and accurate analytical method is needed for their identification and characterization. Here we report a method to profile the alkaloids in RC based on liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (LC–Q-TOF-MS/MS). A total of 16 alkaloids belonging to four different classes were identified by comparison with authentic standards. The fragmentation pathway of each class of alkaloid was clarified and their differences were elucidated. Furthermore, based on an analysis of fragmentation pathways and alkaloid profiling, a rapid and accurate method for the identification of unknown alkaloids in RC is proposed. The method could also be useful for the quality control of RC.

Escherichia coli tetracycline efflux determinants in relation to tetracycline residues in chicken

ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS). MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tcr) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%). ResultsPCR analysis indicated that TcrE. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels. ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.

Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry

A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

Determination of Aflatoxins in Medicinal Herbs by High‐performance Liquid Chromatography–Tandem Mass Spectrometry

We report a rapid and accurate method to determine the natural occurrence of aflatoxins (AFs) B1, B2, G1 and G2 in medicinal herbs and the analysis of 174 commercial samples by this method. The aim of the present work is to examine the occurrence of the aflatoxins B1, B2, G1 and G2 in common medicinal herbs. The AFs were extracted, purified by immunoaffinity column and analysed by high-performance liquid chromatography-tandem quadrupole mass spectrometry with electrospray ionisation (HPLC-MS/MS). The AFs can be separated within 6 min using an Agilent XDB C₁₈-column. The target analyte AFB1 could be detected at 0.14 µg/kg. A good linear relationship was found for AFG1 and AFB1 in 1-100 pg and AFG2 and AFB2 in 0.8-30 pg (r > 0.9995). The analyte recovery under three different spiking levels was 64-100% with the relative standard deviations (RSD) below 8.19%. This simple and accurate method effectively eliminates false positive detection and can be used to determine the AFs in medicinal herbs to control product quality. We found that in the 174 samples tested, 27 were contaminated with AFs. The incidences of AFB1, AFB2, AFG1 and AFG2 in the samples tested were 15.52%, 14.37%, 6.32% and 2.30%, respectively. We proposed 10 µg/kg total AFs and 5 µg/kg AFB1 as the reasonable maximum limits (ML) in medicinal herbs, and there are 10 samples (5.71% occurrence) in our test that exceeded this proposed limit.

Ocular Pharmacokinetics of Carnosine 5% Eye Drops Following Topical Application in Rabbit

To evaluated the ocular pharmacokinetics of carnosine (CAR, a biologically active dipeptide which occurs naturally throughout the human body) 5% eye drops following topical application. CAR 5% eye drops were topically applied repeatedly (50 μL × 4) at an interval of 5 min. Aqueous humor and lens were collected after 5, 15, 30, 45, 60, 90, 120, 150, and 180 min. CAR concentration was determined by high performance liquid chromatography-tandem quadrupole mass spectrometer (HPLC-MS/MS). CAR concentration in treated eyes was significantly higher than control eyes. Peak concentration (C(max)) of carnosine in treated aqueous humor occurred 60 min following topical administration, with the administrated concentration (total-endogenous concentration) of 40.9 ± 18.9 μg/mL. The area under the concentration-time curve between 0 and 180 min (AUC(0-180)) was 3,276.8 (μg/mL) × min. CAR concentration in treated lens rises to effective level rapidly and changes slightly with time after topical administration. The administrated concentration of car in lens at the last time point (180 min, 1.92 ± 1.65 μg/mL) was not significantly different with the highest value (15 min, 2.11 ± 1.83 μg/mL). CAR 5% eye drops were likely to be absorbed into aqueous humor efficiently and accumulated in lens. More attention should be put onto enhancing the penetration of CAR into lens capsule.

Salt Loading Increases Urinary Excretion of Linoleic Acid Diols and Triols in Healthy Human Subjects

Increased dietary linoleic acid has been associated with reduced blood pressure in clinical and animal studies possibly mediated by prostaglandins. Urinary linoleate and prostaglandin metabolite excretion were investigated in subjects exposed to a salt-loading/salt-depletion regimen. Twelve healthy subjects were recruited from the New Orleans population (before Hurricaine Katrina) and admitted to the Tulane-Louisiana State University-Charity Hospital General Clinical Research Center after a 5-day outpatient lead-in phase on a 160-mmol sodium diet. On inpatient day 1, the subjects were maintained on the 160-mmol sodium diet, and a 24-hour urine specimen was collected. On day 2, the subjects received 2 L of IV normal saline over 4 hours and continued on a 160-mmol Na(+) diet (total: 460 mmol of sodium). Two 12-hour urine collections were obtained. On day 3, the subjects received three 40-mg oral doses of furosemide, two 12-hour urine collections were obtained, and the subjects were given a 10-mmol sodium diet. Urinary oxidized lipids were measured by high-performance liquid chromatography-tandem quadrupole mass spectroscopy. The excretion of the urinary linoleate metabolites, dihydroxyoctadecamonoenoic acids, and trihydroxyoctadecamonoenoic acids increased significantly during intravenous salt loading as compared with day 1 and the salt-depleted periods. The urinary excretion of 6-keto- prostaglandin F1alpha was unaffected by salt loading but was dramatically increased 7- to 10-fold by salt depletion. Prostaglandin E2 excretion was positively correlated with sodium excretion. The salt-stimulated production of linoleic acid diols and triols may inhibit tubular sodium reabsorption, thereby assisting in the excretion of the sodium load.