Ultra-fast Liquid Chromatography-tandem Mass Research Articles

Trace-level quantification of NDMA in levosulpuride active pharmaceutical ingredient and tablet formulation Using UFLC-MS/MS

Nitrosamine impurities identified in several pharmaceuticals during recent times has raised concerns leading to product recalls worldwide and necessitating sensitive liquid and gas chromatographic methods for trace level detection of nitrosamine impurities. This study developed and validated a ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method for the quantification of NDMA in Levosulpuride drug substance and tablet formulation. Current method utilizes a triple quadrupole analyzer, atmospheric pressure chemical ionization (APCI) ionization source and multiple reaction monitoring (MRM) scan mode for the analysis. Chromatographic separation was achieved on a Gemini NX-C18 column (150 × 4.6 mm, 3 µm) maintained at 40 °C. The mobile phase consisted of a binary gradient of solvent A (0.1 % formic acid in water) and solvent B (methanol), with a total run time of 18 minutes. Current method achieved excellent linearity, recovery, precision, and sensitivity. Greenness of the developed method was evaluated using the GAPI, AGREE, and AES metrics. Current method is sensitive and selective for NDMA in levosulpuride drug substance and tablet formulations and can be employed for routine quality control analysis in pharmaceutical industry.

Simultaneous multianalyte trace-level quantification of eight genotoxic nitrosamine impurities in valsartan Active Pharmaceutical Ingredient and tablet formulation using UFLC-MS/MS and greenness assessment

Valsartan, a widely prescribed antihypertensive drug, was identified for the presence of carcinogenic nitrosamine impurities in 2018, leading to product recalls worldwide and necessitating sensitive liquid and gas chromatographic methods for trace level detection of nitrosamine impurities. This study developed and validated an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method for the quantification of eight genotoxic nitrosamines (NDMA, NDEA, NDPA, NEIPA, NDIPA, NMBA, NDBA, and NMPA) in valsartan drug substance and tablet formulations. The method employed a triple quadrupole analyzer, atmospheric pressure chemical ionization (APCI) ionization source and multiple reaction monitoring (MRM) scan mode for the analysis. Chromatographic separation was achieved on a Phenomenex biphenyl column (150 × 4.6 mm, 3 µm) maintained at 55 °C. The mobile phase consisted of a binary gradient of solvent A (0.1 % formic acid in water) and solvent B (0.1 % formic acid in methanol), with a total run time of 20 min for the sensitive and specific detection of the analytes. Method validation demonstrated excellent linearity, recovery, precision, and sensitivity. The greenness of the developed analytical method was critically assessed through comprehensive evaluations using the GAPI, AGREE, and AES metrics and the results obtained are compared with the reported methods in the literature. This novel UFLC-MS/MS method offers a reliable and sensitive approach for routine quality control analysis of nitrosamine impurities in Valsartan drug substance and tablet formulations.

Method Development and Validation for Quantification of Quercetin in Blood Plasma of Wistar Rats Using LC-MS/MS

Background: Quercetin is a flavanol that has demonstrated pharmaceutical properties such as anti-inflammatory, antioxidant, and anti-carcinogenic properties. However, parenteral formulations of quercetin are currently not in widespread use due to its poor aqueous solubility, fast metabolism, and low bioavailability. Objective: This study aimed to develop a quick, simple, and accurate method for the quantification of quercetin using ultra-fast liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods: A rapid and sensitive LC-MS/MS method was developed and fully validated for the quantification of quercetin in rat plasma after intravenous administration. Quercetin reference standard was used for the method development as well as in-vivo validation. ACQUITY UPLC BEH C18 Column (2.1 x 50 mm, 1.7 μm) was used for the chromatographic separation. The mobile phase consisted of solution A (water with 0.1% formic acid) and solution B (methanol: acetonitrile with 0.1% formic acid in the ratio of 1:1) with a flow rate of 0.350 μL/min. Further, the method was applied to quantify and pharmacokineticly profile quercetin in the blood plasma of outbred male and female Wistar rats. Results: The accuracy of the method was calculated for intraday and inter-day, which came out as ≤ 85.23% and 84.87%, respectively. The precision of the method calculated for intraday was ≤3.02%, and for inter-day was ≤2.75%. The percentage recovery was found to be ≤85.23% for intraday and ≤84.87% for inter-day. The Relative Standard Deviation was 0.04 for intraday and 1.10 for inter day, respectively. Conclusion: The developed method has an advantage over other reported methods because of its short run time of 6 minutes as well as its short time of data registration of approximately 2.5 minutes. This method can be used for the routine analysis of quercetin in vivo animal studies.

The compatibility rationality of Sijunzi decoction based on integrated analysis of tissue distribution and excretion characteristics in spleen deficiency syndrome rats

Ethnopharmacological relevanceAs a classical prescription for treating spleen deficiency syndrome (SDS), Sijunzi decoction (SJZD) is composed of Ginseng Radix et Rhizoma (RG, Panax ginseng C.A.Mey.), Atractylodes Macrocephalae Rhizoma (AM, Atractylodes macrocephala Koidz.), Poria (Poria cocos (Schw.) Wolf) and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle (GRP, processed from Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L.). The non-polysaccharides (NPSs) are the pharmacodynamic substance basis of SJZD, whose pharmacokinetics in SDS rats were elaborated previously. Further study on their tissue distribution and excretion properties is of significance for understanding the compatibility laws of SJZD. Aim of the studyThe aim was to unravel the tissue distribution and excretion characteristics of NPSs of SJZD in SDS rats, and explore the scientific connotation of SJZD compatibility. Materials and methodsA validated ultrafast liquid chromatography tandem mass spectrometry method was developed for monitoring the accurate dynamics of sixteen components in the tissues, feces and urine of SDS rats. The four incomplete formulae of SJZD were prepared by randomly deleting one herb to uncover the herb-herb interactions. ResultsAll components of NPSs in SJZD were distributed in the tissues, except for ononin in the heart. Among them, glycyrrhetinic acid and atractylenolide III were more abundant in the liver and lung, respectively, while other components were enriched in the ileum, especially saponins. The evaluation of fecal excretion and urinary excretion revealed the low cumulative excretion of all components. The comparative analysis of incomplete formulae indicated that the tissue distribution and excretion became faster after removing Poria from SJZD, while a lack of RG led to slower tissue distribution. The tissue distribution at most time points was reduced when AM was absent. Further comprehensive visualization implied that SJZD compatibility can improve tissue distribution of the NPSs, especially ginsenosides and atractylenolide, at the specific time periods. ConclusionThe tissue distribution and excretion characteristics of NPSs of SJZD were elucidated in current research. Meanwhile, this study proposed new insights into the mechanism of SJZD compatibility rationality.

Highly Sensitive and Ultrafast Liquid Chromatography-tandem Mass Spectrometry Internal Standard Method for Determination of Alpha-Tocopherol in Serum and Application of Validated Method on Patient Serum Samples in Pakistan.

To optimize and validate a specific, sensitive and fast liquid Chromatography coupled to triple quadrupole Mass Spectrometric (LC-MS / MS) technique for accurate detection of serum α-tocopherol (Vitamin E) levels. An experimental based study. The Clinical and Forensic Toxicology section of Chughtai Lab, Jail Road Lahore, from April to September 2022. Methanol was used to deproteinize serum samples. The chromatographic separation was achieved using an Agilent Infinity-Lab Poroshell 120EC-C18 column, Agilent 6470 LC-MS/MS (equipped with an Electron Spray Ionization source) in gradient elution mode using 0.1% LCMS grade formic acid in water and LCMS-grade methanol as mobile phases. Hexa-deuterated α-tocopherol was employed as internal standard to minimise matrix interferences. The retention time of α-tocopherol was 3.0 ± 0.1 minutes. The linear concentrations obtained were ranged from 0.05-2 mg/dL with ≥0.985% coefficient of linearity. Detection and lower quantification limits determined were 0.025mg/dL and 0.05mg/dL, respectively. Recovery ranged from 96.5 to 99.8% and ionization suppression was -15.2% and -15.9% at high and low concentrations of α-tocopherol in serum. Intra-day and inter-day coefficient variation values were 4.2-4.9% and 5.0-5.9%, respectively. An efficient and reliable tandem mass spectrometric technique for vitamin E analysis in serum was optimized, validated, and applied to 80 patient samples. This method has usefulness in clinical application for the accurate determination of vitamin E without potential matrix interferences. Vitamin E, LC-MS/MS, Tocopherol, Internal standard, Validation.

Multi-mycotoxin detection and human exposure risk assessment in medicinal foods

Mycotoxin contamination in medicinal foods has attracted increasing global attention. In this study, a simple and sensitive ultrasonication assisted one-step extraction based ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous detection of multi-mycotoxins in five kinds of medicinal foods rich in starch. Under optimal conditions, the developed technique displayed excellent analytical performances. Limits of detection and quantitation for the six mycotoxins were 0.04–0.25 ng/mL and 0.10–0.67 ng/mL, respectively. Average recoveries at three fortified levels ranged from 75.33 % to 118.0 %. Real-world application in 103 batches of medicinal foods displayed that 58 samples were positive with one or more mycotoxins at an occurrence rate of 56.31 % (58/103). Coix seed gave the highest positive rate of 96.15 %, followed by Lily (90 %), Chinese yam (50 %), Lotus seed (34.04 %) and Malt (30 %). Zearalenone had the highest positive rate of 28.16 % with contents in 5 Coix seeds exceeding the maximum residue limit (MRL), followed by aflatoxin B1 of 27.18 % (28/103) with contents in 7 Coix seed and 10 Lotus seeds over its MRL, and ochratoxin A (OTA) of 11.65 % with contents in 1 Lotus seed and 5 Lily samples greater than its MRL. Exposure risk assessment indicated that Coix seed and Lotus seeds that were susceptible to aflatoxins posed great threats to human health. Long-term consumption of Lily that was easily contaminated with OTA were also harmful. This work provides a robust platform for multi-mycotoxin monitoring in medicinal foods to protect the consumers from potential health risks.

Drug-polysaccharide/herb interactions and compatibility rationality of Sijunzi decoction based on comprehensive pharmacokinetic screening for multi-components in rats with spleen deficiency syndrome

Ethnopharmacological relevanceSijunzi decoction (SJZD) is composed of four herbs, namely Ginseng Radix et Rhizoma (RG, Panax ginseng C.A.Mey.), Atractylodes Macrocephalae Rhizoma (AM, Atractylodes macrocephala Koidz.), Poria (Poria cocos (Schw.) Wolf), and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle (GRP, derived from Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L.) based on the compatibility theory of traditional Chinese medicine (TCM), which is a classical formula for the treatment of spleen deficiency syndrome (SDS) in TCM. The polysaccharides and non-polysaccharides (NPSs) composition represented by flavonoids, saponins and terpenoids are the important pharmacodynamic material basis of SJZD. Aim of the studyThe aim of this study was to investigate the pharmacokinetic characteristics of SJZD in normal rats and SDS rats, and explore the potential interactions between NPSs and polysaccharides in SJZD, as well as the compatibility rationality of SJZD. Materials and methodsSDS model was established by oral administration of Radix Rhei (Rheum officinale Baill.) extract, loaded swimming, and intermittent fasting. A rapid, sensitive and reliable ultrafast liquid chromatography tandem mass spectrometry (UFLC–MS/MS) method was developed for the simultaneous analysis of fifteen representative compounds in rat plasma to investigate the differences in pharmacokinetics between normal and SDS rats. The SJZD-NPS samples were prepared by removing the polysaccharides of SJZD to explore the interactions between NPSs and polysaccharides of SJZD. According to the compatibility theory of TCM, four incomplete formulae of SJZD were obtained by randomly removing an herb (also called 'que fang' in TCM), and their pharmacokinetic differences were compared to elucidate the rationality of SJZD compatibility with oral administration to SDS rats. ResultsThe established UFLC–MS/MS method showed perfect performance in simultaneously analyzing fifteen compounds of SJZD in rat plasma. Compared with normal rats, the absorption efficiency of NPSs in SDS rats was lower, accompanied by the prolonged residence time (Cmax and AUC0-t reduced, while MRT0-t increased). Polysaccharides have the potential to enhance intestinal metabolism of glycosides among these components, thereby contributing to the circulating distribution of corresponding metabolites (e.g. aglycones). Furthermore, the compatibility of the four herbs in SJZD could alter their pharmacokinetic characteristics, and potentially improve the absorption of the effective components of RG and AM, which is in accordance with the principle that “monarch” and “minister” herbs play a major role in TCM. In detail, the improved absorption of ginsenosides was mainly regulated by GRP (the “guide” herb in SJZD), together with the effects of AM (“minister” herb) and Poria (“adjuvant” herb) on the pharmacokinetics of components in GRP, implying that herb-herb interactions existed in SJZD and demonstrated the compatibility rationality of SJZD potentially. ConclusionThis study laid a solid foundation for revealing the pharmacodynamic material basis and subsequent action mechanism of SJZD, as well as provided new insights into the compatibility of SJZD. The comprehensive pharmacokinetic approach adopted in the current research also provides a valuable strategy for TCM formulae research.

Effects of high-altitude environment on pharmacokinetic parameters of gliquidone in rats.

To investigate the effect of high-altitude hypoxia on the pharmacokinetics parameters of gliquidone. Twelve healthy male Wistar rats were randomly divided into plain group and high-altitude group with 6 rats in each group. Blood samples were collected after intragastric administration of gliquidone (6.3 mg/kg). Ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was used to determine the concentration of gliquidone in rat plasma samples. And the expression of CYP2C9 in rat liver tissues was determined by Western blotting. Compared with the plain group, the peak concentration of gliquidone in the high-altitude rats was significantly increased, the absorption rate constant was decreased, the elimination rate constant and the absorption half-life were increased, the elimination half-life was shortened, the mean residence time and apparent volume of distribution were decreased (all P<0.05). Western blotting showed that the expression of CYP2C9 was significantly up-regulated in the liver tissues of high altitude group rats, compared with the plain group (4.18 ±0.06 vs. 2.13±0.06, t=11.57, P<0.01). Under the high-altitude hypoxia environment, the absorption of gliquidone in rats was reduced and the metabolism was accelerated in rats, which may be related to the up-regulation of CYP2C9 expression in liver tissues.

Short-term administration of Polypodium leucotomos extract does not inhibit CYP3A4-mediated metabolism of midazolam in healthy subjects: an open-label, two-period, fixed-sequence study.

The extract of Polypodium leucotomos is used as a dietary supplement for its ultraviolet radiation-protective properties. Polypodium leucotomos extract reportedly inhibits CYP3A, which is important for drug metabolism in vitro in human microsomes and in vivo in rats. Inthis study, we explored the inhibitory effect of the P. leucotomos extract on CYP3A4-mediated midazolam metabolism in humans. This open-label, two-period, fixed-sequence study was performed on six healthy, Japanese, male volunteers. During period 1 (control), midazolam (1 mg) was orally administered. After a wash-out period of at least 5 days, period 2 was initiated. Subjects ingested P. leucotomos extract (240 mg) once in the morning and once at noon on the day before midazolam administration, and once the next morning (thrice overall). Midazolam was administered as in period 1. Blood samples were regularly collected for 8 hours after drug administration, and serum midazolam concentration was determined by ultra-fast liquid chromatography-tandem mass spectrometry. The pharmacokinetic parameters of midazolam were calculated and compared between the two periods. The area under the concentration-time curve was 19.18 ± 3.65 ng h/ml, maximum serum concentration was 7.81 ± 1.25 ng/ml, and half-life was 2.32 ± 0.35 hours during period 2. These parameters did not differ from those recorded in period 1 (area under the concentration-time curve: 18.74 ± 2.97 ng h/ml, maximum serum concentration: 8.78 ± 1.67 ng/ml, half-life: 2.52 ± 0.52 h). Therefore, short-term oral administration of P. leucotomos extract did not cause food-drug interactions mediated by CYP3A4 inhibition in humans.

Adulteration identification of wheat flour in chestnut flour based on differences in mycotoxin contamination by liquid chromatography-tandem mass spectrometry

建立了分散固相萃取-超快速液相色谱-串联质谱法同时测定板栗粉和小麦粉中43种真菌毒素的方法,对48份板栗粉和80份小麦粉样品的污染状况进行调查,筛选出5种专属于小麦粉的标志性真菌毒素。样品采用84%(v/v)乙腈水溶液提取,提取液采用C18结合增强型脂质去除净化剂(EMR-Lipid)净化,采用响应曲面-中心组合设计优化分散固相萃取净化方法。净化液在BEH C18色谱柱(100 mm×2.1 mm, 1.7 μm)上分别采用0.1%甲酸水溶液和含0.1%甲酸的甲醇-乙腈(1:1, v/v)(电喷雾正离子模式)、水和乙腈(电喷雾负离子模式)为流动相进行梯度洗脱,分别采用电喷雾电离(ESI)正负离子模式检测,基质匹配曲线外标法定量。板栗粉中真菌毒素的3水平加标回收率在72.4%~109.4%之间,相对标准偏差(RSD)<7.5%;小麦粉中真菌毒素的3水平加标回收率在70.7%~112.9%之间,RSD<9.3%;两种基质中43种真菌毒素的定量限均在0.1~20.0 μg/kg之间,方法线性相关系数均大于0.9991。利用所建立的方法监测了128份样品,结果表明,两种基质普遍受到真菌毒素污染,其中脱氧雪腐镰刀菌烯醇及其衍生物3-乙酰化-脱氧雪腐镰刀菌烯醇、15-乙酰化-脱氧雪腐镰刀菌烯醇、雪腐镰刀菌烯醇、去环氧-脱氧雪腐镰刀菌烯醇仅在小麦粉中检出。采用GB 5009.111-2016同位素稀释液相色谱-串联质谱法验证,检测结果与本方法一致。所建立的方法简便、快速、灵敏、准确,可有效满足板栗粉和小麦粉中真菌毒素残留的检测要求,脱氧雪腐镰刀菌烯醇及其4种衍生物可以作为两种食品的掺假标志物。

The Effect of Vitamin D3 and Silver Nanoparticles on HaCaT Cell Viability.

Vitamin D3, known to regulate bone homeostasis, has recently been shown to have many pleiotropic effects in different tissues and organs due to the presence of its receptor in a wide range of cells. Our previous study demonstrated that vitamin D3 was able to increase the wound healing respect to the control sample, 24 h after cutting, without however leading to a complete repair. The aim of the study was to combine vitamin D3 with silver nanoparticles to possibly enable a faster reparative effect. The results showed that this association was capable of inducing a complete wound healing only after 18 h. Moreover, a treatment of vitamin D3 + silver nanoparticles yielded a small percentage of keratinocytes vimentin-positive, suggesting the possibility that the treatment was responsible for epithelial to mesenchymal transition of the cells, facilitating wound healing repair. Since vitamin D3 acts via sphingolipid metabolism, we studied the expression of gene encoding for the metabolic enzymes and protein level. We found an increase in neutral sphingomyelinase without involvement of neutral ceramidase or sphingosine kinase2. In support, an increase in ceramide level was identified by Ultrafast Liquid Chromatography–Tandem Mass Spectrometry, suggesting a possible involvement of ceramides in wound healing process.

Contamination status and the health risk evaluation of dietary exposure of quinolone and tetracycline antibiotics in animal derived foods in Ningbo City from 2018 to 2020

To investigate the dietary exposure of Ningbo residents to quinolones and tetracyclines antibiotics in animal derived foods, so as to estimate the health risk caused by the exposure. Animal derived foods in Ningbo markets from 2018 to 2020 were collected and analyzed by ultra-fast liquid chromatography-tandem mass spectrometry. Based on the result of the measurements, median(M), P97.5, average and the maximum values of the data were obtained. Coupling the food intake data of residents in Zhejiang Province, an international point estimate model was applied to evaluate the health risk caused by the dietary exposure. Enrofloxacin, ciprofloxacin, ofloxacin, doxycycline, oxytetracycline were detected in freshwater fishes, cultured pseudosciaena crocea, freshwater shrimps, chicken, eggs and pork. The detection rates of enrofloxacin, ciprofloxacin, ofloxacin, doxycycline, oxytetracycline were 21.2%(77/363), 11.6%(42/363), 2.8%(10/363), 1.4%(5/363), 0.6%(2/363), respectively. The dietary exposure of adults and children from animal derived foods were in the range of 0.8-909.0 and 0.6-518.9 ng/(kg·d), respectively. The hazard quotient(HQ) values were in the range of 0.000030-0.17. Quinolone and tetracycline antibiotics such as enrofloxacin and oxytetracycline have no dietary health risk to the population.

Quality Evaluation of Taxilli Herba from Different Hosts Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Multivariate Statistical Analysis.

Taxilli Herba (TAXH) is an important traditional Chinese medicine with a long history, dating from the Eastern Han Dynasty to the present times. However, the active constituents in it that parasitize different hosts vary, affecting its clinical efficacy. Given the complexity of the host origins, evaluating the quality of TAXH is critical to ensure the safety and effectiveness of clinical medication. In the present study, a quantitative method based on ultra-fast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-QTRAP-MS/MS) was established, which simultaneously determined the content of 33 active constituents, including 12 flavonoids, 4 organic acids, 12 amino acids, and 5 nucleosides in 45 samples. Orthogonal partial least squares discriminant analysis (OPLS-DA) was employed to classify and distinguish between TAXH and its adulterants, Tolypanthi Herba (TOLH). A hierarchical clustering analysis (HCA) was conducted combined with a heatmap to visually observe the distribution regularity of 33 constituents in each sample. Furthermore, gray relational analysis (GRA) was applied to evaluate the quality of samples to get the optimal host. The results demonstrated that TAXH excelled TOLH in quality as a whole. The quality of TAXH parasitizing Morus alba was also better, while those that were parasitic on Cinnamomum camphora and Glyptostrobus pensilis had relatively poor quality. This study may provide comprehensive information that is necessary for quality control and supply a scientific basis for further exploring the quality formation mechanism of TAXH.

Vitamin D3 Enriches Ceramide Content in Exosomes Released by Embryonic Hippocampal Cells.

The release of exosomes can lead to cell–cell communication. Nutrients such as vitamin D3 and sphingolipids have important roles in many cellular functions, including proliferation, differentiation, senescence, and cancer. However, the specific composition of sphingolipids in exosomes and their changes induced by vitamin D3 treatment have not been elucidated. Here, we initially observed neutral sphingomyelinase and vitamin D receptors in exosomes released from HN9.10 embryonic hippocampal cells. Using ultrafast liquid chromatography tandem mass spectrometry, we showed that exosomes are rich in sphingomyelin species compared to whole cells. To interrogate the possible functions of vitamin D3, we established the optimal conditions of cell treatment and we analyzed exosome composition. Vitamin D3 was identified as responsible for the vitamin D receptor loss, for the increase in neutral sphingomyelinase content and sphingomyelin changes. As a consequence, the generation of ceramide upon vitamin D3 treatment was evident. Incubation of the cells with neutral sphingomyelinase, or the same concentration of ceramide produced in exosomes was necessary and sufficient to stimulate embryonic hippocampal cell differentiation, as vitamin D3. This is the first time that exosome ceramide is interrogated for mediate the effect of vitamin D3 in inducing cell differentiation.

Pharmacokinetic and metabolism study of ginsenoside Rb2 in rat by liquid chromatography combined with electrospray ionization tandem mass spectrometry.

In this study, a simple and rapid ultra-fast liquid chromatography tandem mass spectrometry method was established and validated to determine ginsenosides Rb2 in rat plasma. Acetonitrile-mediated protein precipitant was applied to the sample preparation. Chromatographic separation was carried out on an Acquity UPLC HSS T3 column (100 × 2.1mm, 1.8μm). The analytes were monitored using multiple reactions monitoring mode with precursor-to-product ion transitions at m/z 1077.4-945.3 and m/z 799.8 → 637.8 for ginsenoside Rb2 and internal standard, respectively. The mobile phase was composed of 0.1% formic acid aqueous solution and acetonitrile. The assay showed excellent linearity over the concentration range of 2-1,000 ng/ml, with correlation coefficient >0.995. The method was further validated for selectivity, precision, accuracy, recovery, and stability according to the US Food and Drug Administration guidelines. The validated method was successfully applied to pharmacokinetic and bioavailability studies of ginsenoside Rb2 in rat plasma. Based on the pharmacokinetic results, ginsenoside Rb2 showed slow clearance and low oral bioavailability (0.15%). In addition, the metabolites of ginsenoside Rb2 in rat urine and feces were characterized according to their accurate masses and fragment ions. The proposed metabolic pathway was deglycosylation.

Determination of trace low molecular mass aldehydes in air by ultra-fast liquid chromatography-tandem mass spectrometry

To establish a rapid and accurate method for the determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in the air by ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS). The air sample was concentrated and derivatived by 3-methyl-2(3 H)-benzothiazolonhydrazone(MBTH), and the effect of derivative conditions including the concentration of MBTH, the pH, the derivative time and temperature was investigated. The stability of derivatives, the cracking mechanism of mass spectrometry, the matrix effect of the method and air sampling efficiency were studied. The chromatographic separation was carried out on a Shim-pack XR-ODS II column(100 mm×2. 0 mm, 2. 2 μm) by using water/methanol solution as the mobile phase with the gradient elution. Detection was performed in positive multi-reaction monitoring(MRM) mode for quantification by using external standard method. The four analytes showed good linear relationship within the range of 1. 00-100 μg/L(calculated by aldehyde) with a correlation coefficient r≥0. 9990. The limits of quantitation(LOQs) of the method(concentrated with 10 L air) were 0. 5 μg/m~3 in air, for acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde. The recoveries of the method were 90. 6%-97. 8% at the three spiked levels, and the relative standard deviations(RSDs) were between 1. 9%-6. 4%(n=6), the average sampling efficiency was between 91. 0%-97. 1%. The developed method is simple, less interference and specificity, and is suitable for the simultaneous rapid determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in air of work place.

Research progress in the application of magnetic solid phase extraction based on carbon based magnetic materials in food analysis

食品中残留的痕量有毒物质严重威胁人体健康,对其进行分析十分必要。然而,食品中有毒物质种类多、量少、基质复杂,需选择适当的样品预处理技术进行提取和净化。磁固相萃取(MSPE)因具有操作简单、省时快速、无需离心过滤、环境友好等优点,被认为是一种高效的样品预处理技术并应用于食品分析中。MSPE中使用的磁性吸附剂的吸附容量和选择性是影响MSPE萃取效率和选择性高低的关键,对所建立分析方法的准确度起着关键作用。碳基磁性材料是具有价格低廉、来源丰富、比表面积大、化学稳定性好、吸附容量高、绿色环保等优点的一类新型功能性磁性材料,可以富集不同性质的有机、无机分析物,在环境分析、生物检测、污染治理等多个领域取得了较大进展。近年来,基于碳基磁性材料的MSPE技术在食品分析预处理领域逐渐得到应用,但尚处于起步阶段,存在巨大的应用潜力。该文以碳基类别(碳纳米管、石墨烯、金属有机骨架衍生碳、活性炭等)为主线,综述了采用MSPE技术,以碳基磁性材料为吸附剂,对食品样品中酯类、真菌毒素、多环芳烃、抗生素、生物碱、酚类、维生素、抗菌药等物质进行萃取,进而采用液相色谱法等进行分析的应用实例,同时阐述了该技术存在的问题,并对其发展方向做出了展望。该综述将为基于碳基磁性材料的MSPE技术在食品分析中的广泛应用提供理论依据和技术支撑。

Pharmacokinetic studies of ginsenosides Rk1 and Rg5 in rats by UFLC–MS/MS

A rapid ultra-fast liquid chromatography tandem mass spectrometry method was developed and validated to determine ginsenosides Rk1 and Rg5, a pair of isomers, in rat plasma, which was successfully applied to their pharmacokinetic studies. Two ginsenosides were given to male Sprague-Dawley rats via intragastrical and intravenous routes, respectively, and the impact of double bond position on the pharmacokinetic features of the two ginsenosides was elucidated in rats. Ginsenoside Rg3 was used as internal standard and ethyl acetate was applied to extract analytes and internal standard. Chromatographic separation was carried out on a reverse-phase UPLC HSS T3 column (100 × 2.1 mm, 1.8 μm). The flow rate was set to 0.4 ml/min. The fragmentation transition was m/z 765.4 → m/z 101.1 for two ginsenosides. The mobile phases were composed of 0.1% formic acid aqueous solution and acetonitrile. The linear range was 2-1,000 ng/ml for the two ginsenosides. Intra- and inter-day precisions were <11.67%, and accuracy fluctuated from -7.44 to 6.78%. The extraction recovery, matrix effect and stability were within acceptable levels. After treatment with ginsenosides Rk1 and Rg5, some differences were found in their pharmacokinetic profiles in rats. The maximum plasma drug concentration and the area under the plasma drug concentration-time curve of ginsenoside Rg5 were about 5 times bigger than those of ginsenoside Rk1 after oral administration, and 3 times higher after intravenous administration. The oral bioavailabilities of ginsenosides Rk1 and Rg5 were 0.67 and 0.97%, respectively. The results indicated that ∆20(22) -ginsenosides showed better pharmacokinetic features than ∆20(21) -ginsenosides with the same glycosylation.

Contamination status and the evaluation of dietary exposure of marine biotoxins in seafood in Ningbo City in 2017-2019

Ultra-fast liquid chromatography-tandem mass spectrometry method was developed for the analysis of contamination degree of biotoxins in seafood in Ningbo City from 2017 to 2019 and the assessment of dietary exposure was conducted. Samples were extracted and purified with optimized pretreatment process and then injected for analysis. According to the result of the measurements, an international point estimate model was used to evaluate the dietary exposure of the population. For tetrodotoxin and 16 shellfish toxins monitored routinely, gonyautoxin5(GTX5), tetrodotoxin and homo-yessotoxin(hYTX) had higher detection rate, other toxins including okadaic acid(OA), dinophysistoxin1(DTX1), decarbamoyl gonyautoxin2(dcGTX2) and decarbamoyl gonyautoxin3(dcGTX3) were detected sporadically. The detection rates of TTX、GTX and hYTX were 27%, 52% and 12%, respectively. The concentration ranges of TTX, GTX and hYTX in polluted samples were 0. 003-0. 535, 0. 008-0. 189 and 0. 032-0. 110 mg/kg. The exposure risk indices(ERI) of TTX, GTX5, hYTX, dcGTX2 and dcGTX3 were 2. 5, 0. 026, 0. 0080, 0. 79 and 0. 32, respectively. Marine biotoxins have a lower dietary health risk to the population. It is must be given great attention that in the season of toxic red tide, the detection rates of higher toxic toxins, dcGTX2 and dcGTX3 increased significantly with high risks to human. Moreover, the dietary health risk of tetrodotoxin in routine surveillance in 2019 was higher.

Comparison of content-toxicity-activity of six ingenane-type diterpenoids between Euphorbia kansui before and after stir-fried with vinegar by using UFLC-MS/MS, zebrafish embryos and HT-29 cells

The dried roots of Euphorbia kansui (EK) are especially beneficial for the treatment of edema, but the severe toxicity limits their clinical applications. Euphorbia kansui stir-fried with vinegar (VEK) is traditionally employed to reduce the toxicity of EK. However, the material basis for the toxicity reduction with effectivity conservation is still unclear. Therefore, in this study, a rapid, sensitive, and reliable ultra-fast liquid chromatography tandem mass spectrometry (UFLC-MS/MS) method was firstly established to simultaneously determine six ingenane-type diterpenoids, i.e. kansuiphorin C (1), 5-O-benzoyl-20-deoxyingenol (2), 20-deoxyingenol (3), 3-O-(2’E,4’E-decadienoyl)-20-O-acetylingenol (4), 20-O-(2’E,4’Z-decadienoyl)ingenol (5), and ingenol (6), in EK and VEK based on the processing conversion. Then, the toxicity evaluation on zebrafish embryos and modulation of the expression of aquaporin-3 (AQP3) proteins in HT-29 cells were employed to investigate the toxicity-activity of six compounds. Chromatographic separation was obtained on Waters BEH RP18 column (2.1 mm × 100 mm, 2.5 μm) with the mobile phase composed of 0.1 % formic acid in acetonitrile and water, respectively. The column temperature was 35 ℃ at a flow rate of 0.4 mL min−1. Multiple reaction monitoring was conducted in both positive and negative modes for quantitative analysis. The method was then successfully used for the determination of six compounds in EK and VEK. In addition, 1, 2, 4, and 5 had evident cardiotoxicity, intestinal irritation and nutrient absorption disorders on zebrafish larvae, while no in-vivo toxicity was seen for groups given 3 and 6 (LC50 > 200 μM). Meanwhile, 1, 2, 4, 5, and 6 significantly increased the expression of AQP3 protein (p < 0.05) to promote the excretion of water in the colon. This study demonstrated that toxic ingenane-type diterpenoids converted into the less toxic compounds with the same core structure through the breakage of multiple ester bonds in the side chain. At the same time, the laxative effect was retained, providing useful information for the optimization of the process of EK and quality evaluation of other similar toxic Chinese herbal medicines.