Ionization Triple Quadrupole Tandem Mass Research Articles

Quantitative analysis of erythromycin, its major metabolite and clarithromycin in chicken tissues and eggs via QuEChERS extraction coupled with ultrahigh-performance liquid chromatography-tandem mass spectrometry

A simple, rapid and novel method involving ultrahigh-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (UHPLC-ESI–MS/MS) was developed to simultaneously detect erythromycin, its major metabolite and clarithromycin in chicken tissues (muscle, liver and kidney) and eggs (whole egg, albumen and yolk). Samples were extracted using acetonitrile–water (80:20, v/v), and a Cleanert MAS-Q cartridge was used to perform quick, easy, cheap, effective, rugged, and safe (QuEChERS) purification. The average recoveries were 87.78–104.22 %, and the corresponding intraday and interday relative standard deviations were less than 7.10 %. The decision limits and detection capabilities of the chicken tissues and eggs were 2.15–105.21 μg/kg and 2.26–110.42 μg/kg, respectively. For chicken tissues and eggs, the limits of detection and limits of quantification were 0.5 μg/kg and 2.0 μg/kg, respectively. The proposed method was successfully employed to analyse real samples, demonstrating its applicability.

An integration strategy combined progressive multivariate statistics with anticoagulant activity evaluation for screening anticoagulant quality markers in Chinese patent medicine

Ethnopharmacological relevanceThe cardiovascular and cerebrovascular diseases affect human health globally. Naoxintong capsules (NXTs), a famous Chinese Patent Medicine, has been especially applied to treat cerebral infarction and coronary heart disease in clinical practice. The anticoagulant activity of this prescription plays an important role in this course of treatment. Aim of the studyThrombin and factor Xa (FXa) are two key targets considering the anticoagulant activity. The purpose of this investigation is to screen the quanlity markers as key thrombin and FXa inhibitors for the anticoagulant activity oriented quality control of Chinese patent medicine. Materials and methodsSimple multi-polar solvent extraction processes using various proportions of solvents were conducted and their thrombin/FXa inhibitory activities were evaluated in vitro. Bivariate correlation analysis (BCA), grey correlation analysis (GCA), and orthogonal partial least squares discriminate analysis (OPLS-DA) were adopted for screening the potential active markers related to the anticoagulant activity. The chemical structures of these active compounds were identified by UHPLC–Q-TOF-MS/MS and their thrombin/FXa inhibitory activity was determined. The molecular docking technology was applied to explore the interaction between the compounds and targets. The contribution of these anticoagulant active ingredients in NXT was also investigated. Last but not the least, the contents of these markers in NXT were determined by liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-MS/MS) method. ResultsThe results showed that the NXT extract exhibited great activity against thrombin and FXa, especially extracted by 75% methanol (v/v). Six marker compounds with potential anticoagulant activity were screened out. Therein, four of the active compounds owing thrombin inhibitory activity (paeoniflorin, lithospermic acid, salvianolic acid B, Z-ligustilide) and five of the active compounds owing FXa inhibitory activity (3,5-dicaffeoylquinic acid, rosmarinic acid, lithospermic acid, salvianolic acid B and Z-ligustilide). In addition, these active compounds accounted for a large proportion of thrombin/FXa inhibitory activity of NXTs. The binding energy also showed the strong interaction formed by close connection of the compounds to the residues of targets. ConclusionsThe proposed integrated stategy could be an efficient strategy to screen potential thrombin/FXa inhibitors for the bioactivity related quanlity control of Chinese patent medicine.

Simultaneous determination of 11 alkaloids in rat plasma by LC-ESI-MS/MS and a pharmacokinetic study after oral administration of total alkaloids extracted from Naucleaofficinalis

Ethnopharmacological relevanceNauclea officinalis, a widely used Li medicine, has been used for the treatment of cold, fever, bronchitis, pneumonia, acute tonsillitis, and other ailments. Modern pharmacological studies have demonstrated that the most abundant and active components in N. officinalis are alkaloids, which possess various biological properties such as antibacterial and antitumor activities. Aim of the studyTo investigate the phytochemical profile of a selected group of alkaloids from the N. officinalis total alkaloids, and to determine the chemical profile of the alkaloids extracted from rat plasma. Further investigation was conducted to determine the pharmacokinetic behaviors of 11 selected major alkaloids, including pumiloside, naucleoxoside A, naucleoxoside B, nauclefine, angustidine, angustoline, (3S,19S)-3,14-dihydroangustoline,[α]D20: (−)191°, (3S,19R)-3,14-dihydroangustoline, [α]D20: (−) 294.7°, strictosamide, angustine, and 3,14-dihydroangustine. Materials and methodsN. officinalis total alkaloids were extracted with 79% ethanol and enriched with AB-8 macroporous resin. The phytochemical profile of alkaloids from the N. officinalis total alkaloids and the chemical profile of the alkaloids extracted from rat plasma were first analyzed by UPLC-Q-TOF-MS/MS. A simple, convenient, and sensitive LC-ESI-MS/MS method was subsequently developed and validated for the simultaneous determination of major active alkaloids in rat plasma after oral administration of N. officinalis total alkaloids. After addition of an internal standard (verapamil), plasma samples were pretreated first by protein precipitation with methanol and then underwent liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved using a Waters BEH C18 column (2.1 mm × 100 mm, 1.7 μm) at 30 °C, with gradient elution using a mobile phase consisting of 0.1% formic acid aqueous solution (A) and acetonitrile (B), a flow rate of 0.2 mL/min, and a total run time of 30 min. The detection was performed using an electrospray ionization triple quadrupole tandem mass spectrometer with multiple reaction monitoring and positive ionization mode. ResultsBased on the fragmentation patterns of 11 authentic alkaloids and previous reports, 55 alkaloids were identified or tentatively identified in the N. officinalis total alkaloids. Among them, 25 alkaloids were absorbed through the gastrointestinal tract in rats after administration of the N. officinalis total alkaloids. The 11 alkaloids were selected for quantitative analysis. The established quantitative method was fully validated and proved to be sensitive and specific. Satisfactory linearity of the 11 alkaloids obtained in the respective concentration ranges (r > 0.9931). The lower limits of quantification for strictosamide was 20.86 ng/ml, and the other ten alkaloids were all less than 4.47 ng/ml in rat plasma. The intra-and inter-day precision was less than 15% for all 11 alkaloids in terms of relative standard deviation, and the accuracies ranged from −11.4% to 11.1% in terms of relative error. Extraction recovery, matrix effect, and stability were within the required limits in rat plasma. ConclusionThe validated method was successfully applied to investigate the pharmacokinetics of the 11 alkaloids in rat plasma after oral administration of N. officinalis total alkaloids. Eleven alkaloids were rapidly absorbed to achieve a maximum plasma concentration with Tmax from 0.25 h to 1.5 h after oral administration. The pharmacokinetic parameters and plasma concentration-time profiles will prove valuable in pre-clinical and clinical investigations on the disposition of N. officinalis total alkaloids.

Extracellular and Intracellular Angiotensin II Regulate the Automaticity of Developing Cardiomyocytes via Different Signaling Pathways.

Angiotensin II (Ang II) plays an important role in regulating various physiological processes. However, little is known about the existence of intracellular Ang II (iAng II), whether iAng II would regulate the automaticity of early differentiating cardiomyocytes, and the underlying mechanism involved. Here, iAng II was detected by immunocytochemistry and ultra-high performance liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry in mouse embryonic stem cell–derived cardiomyocytes (mESC-CMs) and neonatal rat ventricular myocytes. Expression of AT1R-YFP in mESC-CMs revealed that Ang II type 1 receptors were located on the surface membrane, while immunostaining of Ang II type 2 receptors (AT2R) revealed that AT2R were predominately located on the nucleus and the sarcoplasmic reticulum. While extracellular Ang II increased spontaneous action potentials (APs), dual patch clamping revealed that intracellular delivery of Ang II or AT2R activator C21 decreased spontaneous APs. Interestingly, iAng II was found to decrease the caffeine-induced increase in spontaneous APs and caffeine-induced calcium release, suggesting that iAng II decreased spontaneous APs via the AT2R- and ryanodine receptor–mediated pathways. This is the first study that provides evidence of the presence and function of iAng II in regulating the automaticity behavior of ESC-CMs and may therefore shed light on the role of iAng II in fate determination.

Simultaneous determination of twenty-five compounds with anti-inflammatory activity in Spatholobi Caulis by using an optimized UFLC-MS/MS method: An application to pharmacokinetic study

As a kind of commonly used Traditional Chinese Medicine in clinical, Spatholobi Caulis (SPC) contains a wide variety of bioactive compounds, including protocatechuate (1), nicotinic acid (2), p-hydroxybenzoic acid (3), salicylic acid (4), 6,9-dihydroxy megastigma-4,7-dien-3-one (5), 8,9-dihydroxy megastigma-4,6-dien-3-one (6), daidzin (7), genistin (8), isolariciresinol (9), ononin (10), 4′,8-dimethoxy-7-O-β-d-glucopyranosyl isoflavone (11), 3′-methoxydaidzein (12), odoratin (13), spasuberol A (14), (+)-pinoresinol (15), 4-hydroxy-3-methoxy cinnamic acid methyl ester (16), (+)-epipinoresinol (17), calycosin (18), 8-O-methylretusin (19), formononetin sodium (20), formononetin (21), biochanin A (22), butesuperin A (23), homovanillyl-4-oxo-nonanoate (24) and (6aR,11aR)-maackiain (25). The pharmacokinetic characteristics of these twenty-five compounds in rat plasma were quantitatively and simultaneously studied using a fast, sensitive and precise ultra fast liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UFLC-MS/MS) method after oral administration of aqueous extract of SPC to rats. The mobile phase consists of acetonitrile and 0.5 mM ammonium acetate in water, and these compounds were well separated at a gradient elution program with flow rate of 0.35 mL/min. Carbamazepine was employed as the internal standard (IS) and all samples were precipitated with MeOH-ACN (2:1, v/v). The analytical method has been proved to be good linearity (R2 ≥ 0.9957), precise, accurate, stable, recovery and matrix effect, which applicated becomingly to study the pharmacokinetic processes of these compounds in rat plasma. In addition, these twenty-five compounds exhibited anti-inflammatory activity on the inflammatory model of NO over production in RAW264.7 cells stimulated by lipopolysaccharide (LPS). Isoflavones, especially compounds 20-22 (The IC50 of which were 22.75 μM, 21.11 μM and 48.29 μM, respectively.) might be the important constituents for anti-inflammatory activity of SPC. This study provides reference values for the clinical application, in-depth study on new dosage forms and pharmacological activities of SPC.

Identification of Polymethylene-Interrupted Polyunsaturated Fatty Acids (PMI-PUFA) by Solvent-Mediated Covalent Adduct Chemical Ionization Triple Quadrupole Tandem Mass Spectrometry.

Pine nuts and other edible gymnosperm seeds contain unusual, bioactive polymethylene-interrupted polyunsaturated fatty acids (PMI-PUFAs), a subset of nonmethylene-interrupted PUFA with (-CH2-)n≥2 intervening between double bonds. Conventional methods for structure elucidation of PMI-PUFAs require special derivatization risking rearrangement artifacts. Here we introduce a facile solvent-mediated (SM) covalent adduct chemical ionization (CACI) system modified with a triple quadrupole MS, which distinguishes PMI-PUFAs from their analogues in direct methyl ester form. The prominent Δ5 desaturated PMI-PUFAs exhibit characteristic fragmentation at C6-7 to yield ω diagnostic ions and share their fragmentation pattern with normal methylene interrupted PUFAs for the α diagnostic ion. H• transfer upon CID dissociation of PMI-PUFAs was found to be dependent on the relative position of isolated lone double bonds and cleavage points. Ginkgo and five species of pine nuts were characterized for their unique Δ5 fatty acid profile, without the need for chemical standards.

Syntheses and analytical characterizations of the research chemical 1-[1-(2-fluorophenyl)-2-phenylethyl]pyrrolidine (fluorolintane) and five of its isomers.

A number of substances based on the 1,2-diarylethylamine template have been investigated for various potential clinical applications whereas others have been encountered as research chemicals sold for non-medical use. Some of these substances have transpired to function as NMDA receptor antagonists that elicit dissociative effects in people who use these substances recreationally. 1-[1-(2-Fluorophenyl)-2-phenylethyl]pyrrolidine (fluorolintane, 2-F-DPPy) has recently appeared as a research chemical, which users report has dissociative effects. One common difficulty encountered by stakeholders confronting the appearance of new psychoactive substances is the presence of positional isomers. In the case of fluorolintane, the presence of the fluorine substituent on either the phenyl and benzyl moieties of the 1,2-diarylethylamine structure results in a total number of six possible racemic isomers, namely 2-F-, 3-F-, and 4-F-DPPy (phenyl ring substituents) and 2"-F-, 3"-F-, and 4"-F-DPPy (benzyl ring substituents). The present study reports the chemical syntheses and comprehensive analytical characterizations of the two sets of three positional isomers. These studies included various low- and high-resolution mass spectrometry platforms, gas- and liquid chromatography (GC and LC), nuclear magnetic resonance (NMR) spectroscopy and GC-condensed phase and attenuated total reflection infrared spectroscopy analyses. The differentiation between each set of three isomers was possible under a variety of experimental conditions including GC chemical ionization triple quadrupole tandem mass spectrometric analysis of the [M+H - HF]+ species. The latter MS method was particularly helpful as it revealed distinct formations of product ions for each of the six investigated substances.

Development of an Accelerated Solvent Extraction Approach for Quantitative Analysis of Chloramphenicol, Thiamphenicol, Florfenicol, and Florfenicol Amine in Poultry Eggs

This manuscript describes a simple, reliable, and sensitive approach that utilizes high-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI/MS/MS) for the selective determination of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in poultry eggs (hen eggs, duck eggs, and goose eggs). Samples were extracted with methanol-ammonium hydroxide-ultrapure water (97:2:1, v/v) via accelerated solvent extraction (ASE) at 80 °C and 1500 psi and defatted with hexane saturated with acetonitrile. The experimental method uses ESI (+) and ESI (−) combination mode, full-scan qualitative analysis, and multiple reaction monitoring (MRM) combined with an internal standard for quantitative analysis. This optimized method was validated according to the requirements defined by the European Union and the Food and Drug Administration. The poultry eggs were spiked with the target compounds at four levels, and the average recoveries were all higher than 88.3%, and the relative standard deviations did not exceed 3.9%. The limits of detection and limits of quantification were 0.04–0.5 μg/kg and 0.1–1.5 μg/kg, respectively. The decision limits were 0.37–102 μg/kg, and the detection capabilities were 0.44–103 μg/kg. Finally, the new approach was successfully applied to the quantitative determination of these analytes in 120 commercial poultry eggs from local supermarkets.

Determination of Impurities and Degradation Products/Causes for <i>m</i>-Iodobenzylguanidine Using HPLC-Tandem Mass Spectrometry

m-Iodobenzylguanidinium hemisulfate (MIBGHS) is a precursor in the preparation of radioiodine-labeled m-iodobenzylguanidine (MIBG), which is used as a radio-imaging and therapy agent for neuroendocrine tumors and myocardial sympathetic nerve function. To ensure the quality and efficacy of the medicine and prevent side effects, the precursor purity, source of impurity, and derivatives have to be determined. In this study, the purity of synthesized MIBGHS and the amount of contaminants therein were determined by high-performance liquid chromatography and ultraviolet detection, gradient eluted by ammonium formate aqueous solution and acetonitrile mobile phase on both C8 and phenyl type column. The impurities were identified on the basis of molecular and fragmented ion mass spectra using of electrospray ionization triple quadrupole tandem mass spectrometry. The results revealed the presence of process-related impurities including m-bromobenzylguanidine (MBrBG) and overreacted byproducts. Stress test results indicated that MIBGHS is stable under acidic and dry thermal conditions for at least 72 h but MIBG aqueous solution was deteriorated slowly when exposed to UV light, thermal, oxidative and alkaline environments. Thus, m-iodobenzylamine, the starting material intended for the synthesis of MIBGHS should be analyzed to ensure that it is free from m-bromobenzylamine impurity. Stored under normal condition (-18°C), MIBGHS is stable for at least 12 months. The chemically labile guanidine and amine groups in MIBGHS are the major causes of its instability, while iodide loss from the phenyl group is a minor cause.

Quantitative Analysis of Phenolic Acids and Flavonoids in Cuscuta chinensis Lam. by Synchronous Ultrasonic-Assisted Extraction with Response Surface Methodology.

An effective ultrasonic-assisted extraction method for the separation of phenolic acids and flavonoids in Cuscuta chinensis Lam. was conducted by combining uniform design (UD) coupled with response surface methodology (RSM) and orthogonal design (OD) experiment. A sensitive and selective high-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-MS/MS) method was applied to quantify the sixteen active ingredients (chlorogenic acid, cryptochlorogenic acid, neochlorogenic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, caffeic acid, hyperin, isoquercitrin, quercetin, campherol, p-coumaric acid, isorhamnetin, rutin, astragalin, and apigenin). The extraction method was optimized with respect to concentration of extraction solvent, extraction time, and ratio of liquid to solid as a consequence of getting a high sensitive and feasible method for simultaneous determination of contents of multiple components and evaluation of quality control of Cuscuta chinensis Lam. from different origins. It was also considered useful and valuable in the further study for quality control of Cuscuta chinensis Lam.

Stereoselective and Simultaneous Analysis of Ginsenosides from Ginseng Berry Extract in Rat Plasma by UPLC-MS/MS: Application to a Pharmacokinetic Study of Ginseng Berry Extract.

The role of ginseng berry extract (GBE) has been attributed to its anti-hyperglycemic effect in humans. However, the pharmacokinetic characteristics of GBE constitutes after oral GBE administration have not been established yet. In this study, stereoselective and simultaneous analytical methods for 10 ginsenosides (ginsenoside Rb1, Rb2, Rc, Rd, Re, Rg1, S-Rg2, R-Rg2, S-Rg3, and R-Rg3) were developed using ultra-performance liquid chromatography, coupled with electrospray ionization triple quadrupole tandem mass spectrometry (UPLC-MS/MS), for the pharmacokinetic study of GBE. Furthermore, the pharmacokinetic profiles of 10 ginsenosides after oral GBE were evaluated in rats. All analytes were detected with a linear concentration range of 0.01–10 µg/mL. Lower limits of detection (LLOD) and quantification (LLOQ) were 0.003 and 0.01 µg/mL, respectively, for all 10 ginsenosides. This established method was adequately validated in linearity, sensitivity, intra- and inter-day precision, accuracy, recovery, matrix effect, and stability. Relative standard deviations for all intra- and inter-precision of the 10 ginsenosides were below 11.5% and accuracies were 85.3–111%, which were sufficient to evaluate the pharmacokinetic study of oral GBE in rats. We propose that Rb1, Rb2, Rc, Rd, Re, Rg1, S-Rg2, R-Rg2 and/or S-Rg3 were appropriate pharmacokinetic markers of systemic exposure following oral GBE administration.

Quantitative analysis of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine in eggs via liquid chromatography-electrospray ionization tandem mass spectrometry

A widely applicable method involving liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (LC-ESI/MS/MS) was developed for the simultaneous determination of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in eggs. Samples were extracted with ethyl acetate-acetonitrile-ammonium hydroxide (49:49:2, v/v) and defatted with hexane saturated with acetonitrile. The analysis was carried out on a mass spectrometer via an electrospray interface operated in the positive and negative ionization modes using deuterated chloramphenicol-d5 as the internal standard. The limits of detection and limits of quantification were 0.04–0.5 μg/kg and 0.1–1.5 μg/kg in eggs, respectively. The average recoveries of the four analytes from egg samples were 90.84–108.23%, with relative standard deviations of less than 9.61%. The corresponding intra-day and inter-day variations were found to be less than 8.11% and 11.30%, respectively. Finally, the new approach was successfully applied to the quantitative determination of these analytes in 50 commercial eggs from local supermarkets.

Development and validation of a UFLC–MS/MS method for simultaneous quantification of sixty-six saponins and their six aglycones: Application to comparative analysis of red ginseng and white ginseng

A new and sensitive ultra fast liquid chromatography coupled with electrospray ionization triple quadrupole tandem mass spectrometry (UFLC–MS/MS) method was developed to evaluate the quality of Red ginseng (RG) and to find out its chemical markers by comparing with multi-batches of RG and white ginseng (WG). This innovative method could quantify sixty-six saponins and their six aglycones including 10 pairs of 20(S) and 20(R) epimers within 35 min simultaneously. All compounds could be determined in individual multiple-reaction monitoring channel without interference, and the optimized method was rapid, accurate, precise, reproducible and efficient. Using the orthogonal partial least squared discriminant analysis, ginsenosides Rg5, Rh4, Rk1, Rs4, F4, and 20(S)-Rg3 were found to be the characteristic components of RG, the six compounds should be suggested as quality control markers to distinguish RG from WG. These findings will be significant for standardizing the processing procedures of RG and ensuring the consistent quality, as well as consequently the efficacy of RG in clinical applications. Results will be helpful in providing crucial chemical profiles of RG.

Aflatoxin M1 contamination of raw cow's milk in five regions of Kosovo during 2016.

During February and August 2016 (winter and summer season), 192 samples of raw bulk tank milk have been collected from small dairy farms in five different regions of Kosova (Prishtina, Prizren, Peja, Mitrovica, and Gjilan). These samples were analyzed for aflatoxin M1 (AFM1) contamination level by ultra-high performance liquid chromatography coupled with electrospray ionization triple quadrupole tandem mass spectrometry (UHPLC-ESI-MS/MS). The limit of quantification for AFM1 was 0.02μg/L and recovery at 0.1-0.5μg/L was 90-95% (coefficient of variation 15-25%). A total of 74 milk samples (38%) were found to be contaminated with AFM1 and 11 samples (5.7%) slightly exceeded the European Union maximum level of 0.05μg/L. The maximum AFM1 level was at 0.082μg/L. There was no relevant difference between summer and winter with regard to AFM1 frequency and levels. Although the frequency of AFM1-positive samples varied between regions, from 7% (Prishtina) to 53% (Prizren), only minor regional differences were observed with regard to average and maximum toxin levels. The high percentage of milk samples which were non-compliant with AFM1 maximum levels indicates that efforts to reduce the contamination levels of aflatoxin B1 in cows feed in Kosovo are necessary.

Comparison of α-glucosidase inhibitory effect and bioactive constituents of Anemarrhenae Rhizoma and Fibrous Roots

Comprehensive utilization of medicinal plant resources is of great significance for sustainable development of traditional Chinese medicines. In the present study, the α-glucosidase inhibitory activities of the rhizome and fibrous root of Anemarrhena Asphodeloides Bunge, were compared detailedly, and a high performance liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-QQQ/MS) method was developed for simultaneous quantification of seven bioactive constituents including neomangiferin, mangiferin, isomangiferin, timosaponin BII, timosaponin B, timosaponin AIII, and timosaponin N in 40 batches of samples. The results demonstrated that fibrous root extracts had more potent α-glucosidase inhibitory activity than rhizome extracts. Mangiferin and isomangiferin were abundant in fibrous root, while the analyzed saponins were rich in rhizome. Based on the chemometrics methods including principal component analysis (PCA), orthogonal partial least square discriminant analysis (OPLS-DA), and partial least square (PLS), mangiferin and isomangiferin might be mainly responsible for α-glucosidase inhibitory activity of the genus. These findings indicate that the established HPLC-QQQ/MS method was proven to be useful and efficient for quality control of Anemarrhena materials, and fibrous root had the potential to be utilized as anti-diabetic medicinal resource.

Quantitative Analysis of Amoxicillin, Amoxicillin Major Metabolites, and Ampicillin in Chicken Tissues via Ultra-Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

This manuscript describes a rapid, sensitive, and specific approach that utilizes ultra-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (UPLC-ESI/MS/MS) for the selective determination of amoxicillin, amoxicillin metabolites, and ampicillin in chicken tissue samples (muscle, liver, and kidney). This optimized method was validated according to the requirements defined by the European Union and the Food and Drug Administration. The extract obtained after extraction and purification of chicken tissues was injected into a UPLC system coupled to a mass spectrometer operated in the positive electrospray MS/MS mode for analysis. The chicken tissues were spiked with the target compounds at levels of 25.0, 50.0, and 100.0 μg/kg, and the results showed that the extraction recoveries were all higher than 84% and the relative standard deviations did not exceed 20%. The limits of detection and limits of quantification were 0.01–1.36 and 0.05–5.44 μg/kg, respectively. The decision limits were 52.62–57.26 μg/kg, and the detection capabilities were 55.23–64.51 μg/kg. Finally, the new approach was verified through quantitative determination of the analytes in tissues from 30 commercial chickens obtained from local supermarkets.

Quantification of Piperazine in Chicken Muscle by Ultra-Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

An ultra-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (UPLC-ESI/MS/MS) method was developed for the detection of piperazine in chicken muscle. Following extraction and purification, the chicken muscle extract was injected into the UPLC system and analyzed. Piperazine detection was performed on a triple-quadrupole mass spectrometer with the ESI interface operating in positive mode. The most sensitive mass transition from the precursor ion to the product ion was 87.1 → 44.1 for piperazine. The coefficient (R2) of piperazine was 0.9995 in the range of 1–200 μg/kg. The recovery and relative standard deviation (RSD) ranged from 102.93 to 111.46% and from 4.57 to 5.28% at 50.0, 100.0 and 200.0 μg/kg adding levels, respectively. Limits of detection (LODs) and limits of quantification (LOQs) were 0.4 and 1.0 μg/kg, respectively. This method was fully validated based on its specificity, sensitivity, linearity, precision, accuracy, matrix effect, and stability results. Compared to other researches, this new method not only omitted the derivative process, which simplify the pre-processing, but also proved a better sensitivity based on its low LOD and LOQ values.

Simultaneous determination of ten Aconitum alkaloids in rat tissues by UHPLC-MS/MS and its application to a tissue distribution study on the compatibility of Heishunpian and Fritillariae thunbergii Bulbus.

A rapid, sensitive and selective ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous determination of ten Aconitum alkaloids in rat tissues. The tissue samples were prepared by a simple procedure protein precipitation with acetonitrile containing 0.1% acetic acid and separated on an Agilent XDB C18 column (4.6 mm×50mm, 1.8μm) using gradient elution with a mobile phase consisting of water and acetonitrile (both containing 0.1% formic acid) at a flow rate of 0.3mL/min. The quantitive determination was performed on an electrospray ionization (ESI) triple quadrupole tandem mass spectrometer using selective reaction monitoring (SRM) under positive ionization mode. The established method was fully validated according to the USA Food and Drug Administration (FDA) bioanalytical method validation guidance and the results demonstrated that the method was sensitive and selective with the lowest limits of quantification (LLOQ) at 0.025ng/mL in rat tissue homogenates. Meanwhile, the linearity, precision, accuracy, extraction recovery, matrix effect and stability were all within the required limits of biological sample analysis. After method validation, the validated method was successfully applied to the tissue distribution study on the compatibility of Heishunpian (HSP, the processed product of Aconitum carmichaelii Debx) and Fritillariae thunbergii Bulbus (Zhebeimu, ZBM). The results indicated that the distribution feature of monoester diterpenoid aconitines (MDAs), diester diterpenoid aconitines (DDAs) and non-ester alkaloids (NEAs) were inconsistency, and the compatibility of HSP and ZBM resulted in the distribution amount of DDAs increased in tissues. What's more, the results could provide the reliable basis for systematic research on the substance foundation of the compatibility of the herbal pair.

Simultaneous analysis of ten phytohormones in Sargassum horneri by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

Phytohormones have attracted wide attention due to their important biological functions. However, their detection is still a challenge because of their complex composition, low abundance and diverse sources. In this study, a novel method of high-performance liquid chromatography with electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous determination of ten phytohormones including indole-3-acetic acid, isopentenyladenine, isopentenyl adenosine, trans-zeatin riboside, zeatin, strigolactones, abscisic acid, salicylic acid, gibberellin A3, and jasmonic acid in Sargassum horneri (S. horneri). The phytohormones were extracted from freeze-dried S. horneri with methanol/water/methanoic acid (15:4:1, v/v/v) analyzed on a Hypersil Gold C18 column and detected by electrospray ionization tandem triple quadrupole mass spectrometry in the multiple reaction monitoring mode. The experimental conditions for the extraction and analysis of phytohormones were optimized and validated in terms of reproducibility, linearity, sensitivity, recovery, accuracy, and stability. Distributions of the phytohormones in the stems, blades, and gas bladder of the S. horneri in drift, fixed, and semi-fixed growing states were investigated for the first time. The observed contents of the phytohormones in S. horneri range from not detected to 5066.67 ng/g (fresh weight). Most phytohormones are distributed mainly in the stems of S. horneri in drift and semi-fixed states.

Simultaneous determination of seven alkaloids in rat plasma by UFLC-MS/MS and its application to a pharmacokinetic study after oral administration of Cerebralcare Granule.

An ultra fast liquid chromatography-tandem mass sepectrometry (UFLC-MS/MS) method was developed for simultaneous determination of seven active alkaloid components (tetrahydropalmatine, corydaline, α-allocryptopine, tetrahydroberberine, tetrahydrocoptisine, tetrahydrocolumbamine and dehydrocorydaline) in rat plasma after oral administration of Cerebralcare Granule. Plasma samples were pretreated by protein precipitation with acetronitrile containing the internal standard diazepam. Chromatographic separation was achieved on a Phenomenex Kinetex C18 column (100×2.1mm, 2.6μm) with gradient elution using mobile phase consisting of acetonitrile -0.1% formic acid in water at a flow rate of 0.3mL/min. The detection was performed on an electrospray ionization triple quadrupole tandem mass spectrometer using multiple reaction monitoring (MRM) with positive ionization mode. The established method was fully validated and proved to be sensitive and specific with lower limits of quantification (LLOQs) all less than 0.0265ng/mL in rat plasma. Good linearities of seven alkaloids were obtained in respective concentration ranges (r>0.9923). The intra- and inter-day precisions were below of 15% for all the seven alkaloids in terms of relative standard deviation (RSD), and the accuracies were ranged from -2.7% to 8.3% in terms of relative error (RE). Extraction recovery, matrix effect and stability were within the required limits in rat plasma. The validated method was successfully applied to investigate the pharmacokinetics of the seven alkaloids in rat plasma after oral administration of Cerebralcare Granule (CG).