Determination of Veterinary Drug Residues in Animal-derived Foods by Liquid Chromatography-Mass Spectrometry

[Objectives]This study was conducted to establish a rapid and effective method for simultaneous extraction of 54 kinds of veterinary drug residues in animal-derived food, including sulfonamides, quinolones, tetracyclines, malachite greens, penicillins, nitroimidazoles, tranquilizers and macrolides, by HPLC-MS. [Methods] The samples were extracted with 80% acetonitrile water(containing 0.1% formic acid), combined with QuEChERS extraction technology and C18 and PSA purification, analyzed by high performance liquid chromatography-mass spectrometry, and quantified by external standard method. The target substances were analyzed on ZORBAX Eclipse C18 chromatographic column using 0.2% formic acid water and 0.2% methanol as mobile phases. The gradient elution mode was used for chromatographic separation and multiple reaction detection. [Results] In the linear range of 0.5-50.0 ng/ml, the linear relationship of the 54 kinds of veterinary drug residues was good, with correlation coefficients(r~2) greater than 0.995, and the detection limits ranged from 0.30 to 1.00 μg/kg. The results showed that the recovery ranged from 75.4% to 118.2% when different matrixes were added for recovery. [Conclusions] This method is simple, efficient, accurate, stable, and highly operable. It is applicable to simultaneous batch screening of veterinary drug residues in animal-derived food, and has high practical application value.

Chemical Components of Achyranthes bidentata Leaves by Ultra High Performance Liquid Chromatography-Mass Spectrometry

[Objectives] To study the chemical components and relative content of Achyranthes bidentata leaves and provide a scientific basis for further development and utilization of A. bidentata leaves.[Methods] The chemical components of A. bidentata leaves were rapidly analyzed using the ultra high performance liquid chromatography-time of flight-high resolution mass spectrometry (UHPLC-TOF-MS).[Results] Thirty eight chemical compounds were identified in samples of A. bidentata leaves collected from Wen County of Henan Province, in which seven chemical compounds had the relative content higher than 5%, linoleic acid reached 25.7% and inokosterone A reached 13.8%.[Conclusions] A. bidentata leaves contain many kinds of chemical compounds. This study is expected to provide a certain basis for further extraction of linoleic acid and inokosterone A.

A Validated Liquid Chromatography-Mass Spectrometry Method for the Detection and Quantification of Oxidative Metabolites of 2,2',4,4'-Tetrabromodiphenyl Ether in Rat Hepatic Microsomes

In the present study, we developed and validated an analytical method using ultra performance liquid chromatography-mass spectrometry (UPLC/MS) for the quantitative determination of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) metabolism by rat hepatic microsomes. BDE-47 is a brominated flame retardant that was widely used in a variety of consumer products and has subsequently been identified as a ubiquitous environmental contaminant. Hydroxy-bromodiphenyl ethers (OH-BDEs) were isolated from rat hepatic microsomes by liquid-liquid extraction. Chromatographic separation was achieved by UPLC on a C18 column with gradient elution using a mobile phase consisting of methanol and water, each containing 0.1% formic acid, at a flow rate of 0.2 mL/min. Detection and quantification were performed using a mass spectrometer in single ion recording mode with negative electrospray ionization. The UPLC/MS method was validated for linearity, limit of quantification (LOQ), accuracy, precision and recovery. The weighted calibration curves (1/X2) were linear over a concentration range of 5 - 250 nM with LOQ values between 5 nM and 50 nM for the individual OH-BDEs. Intra- and inter- day accuracy (%DEV) and precision (%RSD) values ranged from –11.7% to 9.5% and 5.9% to 16.5%, respectively. Recovery values of 70% to 90% were obtained for all OH-BDEs. The validated method allowed us to successfully analyze metabolite formation following incubation of BDE-47 with hepatic microsomes prepared from phenobarbital-treated rats. Results demonstrate that the UPLC/MS method has sufficient sensitivity and reproducibility to fully characterize the in vitro metabolism of BDE-47 and possibly other PBDEs.

CO₂Absorption Solvent Degradation Compound Identification Using Liquid Chromatography-Mass Spectrometry Quadrapole-Time of Flight (LCMSQTOF)

The degradation of the alkanolamine solvent used in the removal of acid gases from natural gas streams due to exposure to contaminants, thermal degradation and presence of oxygen or oxygen containing compounds will change the solvent properties, such as heat transfer coefficient, diffusion coefficient, and mass transfer coefficient of the solvent. Therefore, characterization and quantification of amine degradation product becomes one of the important analyses to determine alkanolamine solvent’s health. In order to identify degradation products of alkanolamine solvent, analytical strategies by using mass spectrometry (MS) as detector have been studied extensively. In this work, due to the low concentration of the amine degradation product, a method was developed for identification of alkanolamine degradation products using LCMS-QTOF technique. A strategy for identification of trace degradation products has been identified. Six (6) alkanolamine degradation products had been identified by using LCMS-QTOF targeted analysis in the blended alkanolamine solvent used in natural gas processing plant. Another fifteen (15) molecular formulas having similarity in chemical structure to alkanolamine degradation products were identified using untargeted analysis strategy, as possible compounds related to degradation products. Using LCMS-QTOF via targeted and untargeted analysis strategy, without tedious column separation and reference standard, enables laboratory to provide a quick and indicative information for alkanolamine solvent’s organic degradation compounds identification in CO2 adsorption, within reasonable analysis time.

Liquid Chromatography-mass Spectrometry Analysis on Effect of Roughage Types on Liver Metabolic in Dairy Cows

The major objective of this study was to determine the effect of corn straw or mixed diet on the small molecule metabolites of liver and milk production of healthy Chinese Holstein cows during lactation.In this study,metabolomic methods based on ultra performance liquid chromatography-mass spectrometry(LC-MS)were used to study the liver metabolites of dairy cows fed on corn straw diet or mixed diet.Ten healthy Chinese Holstein cows were randomly assigned to two groups,under the same management condition,fed different diets respectively,corn straw group(CS)or a mixture of alfalfa hay and Chinese wild rye hay mixed forage group(MF).All the cows were fed for 8 weeks and recorded body weight,dry matter intake,body condition score,fat,protein,lactose,milk yield and the total solids.Livers were sampled from each cow through a liver puncture needle for analysis of a significant difference in small molecule metabolites in cow liver samples from the two different diets.The results suggested that different diet types had significant effects on liver metabolism and milk components in dairy cows.The contents of milk fat,the total solids,milk protein,lactose,dry matter intake(DMI),milk yield,milk protein(%),lactose(%)and milk fat(%)of the corn straw group were significantly lower than those of the mixed forage group(p<0.05);the contents of phosphatidylcholine(PC),histidine,hypoxanthine and mridine in liver tissues of the corn straw group were significantly lower than those in the mixed forage group(p<0.05);acetylcarnitine,uric acid,triacylglycerol(TG),acetal phosphatidylcholine(plasmenyl-PC),acetalphosphatidylethanolamine(plasmenyl-PE)and sphingomyelin(SM)of the corn straw group were significantly higher than those in the mixed forage group(p<0.05).In summary,cows fed on mixed forage diet significantly improved milk yield and lactation performance clearly.

Novelties Filtration Theory of Liquid Chromatography-Mass Spectrometry in Volume Nanotube of Cotton Filament of Layers Woven Fabrics

Objectives of the research to present a modern theory of water purification for multiple purposes entitled “a novelties filtration theory of liquid chromatography-mass spectrometry” is an exceedingly sensitive and specific analytical technique in volume layers woven fabrics that can precisely determine the identities and quantities of compounds within volume Nanotube of cotton filament of layers woven fabrics. The problems are that the filters in the local and international markets have increased complications in configuration, installation and cost without reaching the efficiency that humanity hopes. Throw materials and methods the chromatography-mass spectrometry in layers woven fabrics, and throw the nanotube of cotton filament for purification of water dyes and smells. Industry, in which mass spectrometry is a convenient, versatile method for characterization and identification of process throw the Nanotube of cotton filament for purification of water dyes and smells. Results came up with a theme “innovations in textiles”, and also, for characterization of fibers and contaminants of the fabrics. Additive manufacturing in layers woven fabrics, are the processes used to synthesize a volume object under computer control with successive material layers that have been used and highlighted. The conclusions has included chromatography-mass spectrometry drop, physico-chemical, biological, combined physical-biological and chemical-biological treatment processes recently being developed to meet Jet-filtration, the strict discharging limits set by ASTM standards. Some important aspects of both qualitative and quantitative data analysis have been described and the power of using mass profiles to enhance selectivity and sensitivity has been demonstrated.

Determination of penehyclidine hydrochloride in beagle dog plasma by liquid chromatography-electrospray ionization mass spectrometry and the pharmacokinetic study

To develop a fast and sensitive liquid chromatography-mass spectrometry method for the determination of penehyclidine hydrochloride （PH） in beagle dog plasma. PH and diphenhydramine hydrochloride （internal standard, IS） were extracted with a solvent mixture of petroleum ether-ethyl ether （7：3）. Chromatographic separation was achieved on a reversed-phase Eclipse XDB-C18 column （4.6 mm × 150 mm, 5 um） using the eluent of methanol-water （5 mmol/L ammonium acetate） （90：10, v/v, pH 5.8） as mobile phase. The electrospray ionization source was set at the positive multiple reaction monitoring （MRM） mode. This method involved the use of the [M＋H]^＋ ions of PH and diphenhydramine hydrochloride at m/z 316.4- 128.2 and m/z 256.4-167.2. The calibration curve was linear in the range of 1-1000 ng/mL with a correlation coefficient of 0.9988. The lower limit of quantification was 0.05 ng/mL. The precision, accuracy and recovery of the method were acceptable. Following intravenous injection admires＇ tration at doses of 0.5, 1 and 5 mg/kg PH, the main pharmacokinetic parameters were as the followings, t1/2a 0.33 h, t1/2β 2.44 1% tmax 0.058 1% AUC and Cmax exhibited a linear increase along with the increase of dose. The two-compartment model fit the three dose groups. This method was sensitive, accurate and fast for the determination of concentration of PH in beagle dog plasma. It could be used in pharmacokinetic studies of PH.

Determination of brominated diphenyl ethers in atmospheric particulate matter using selective pressurized liquid extraction and gas chromatography–mass spectrometry with a negative chemical ionization

This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.

Untargeted and targeted mass spectrometry reveal the effects of theanine on the central and peripheral metabolomics of chronic unpredictable mild stress-induced depression in juvenile rats

L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of Ltheanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spectrometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal metabolites in the serum and hippocampus that were considered as potential biomarkers returned to nearnormal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.

Application of Mass Spectrometry (MS)-coupled Techniques in Pesticide Residue Detection

Pesticide residue detection is an important work to ensure the quality safety of agricultural products.In the process of agricultural production,in order to prevent and control agricultural diseases and pests,a certain amount of pesticides need to be used.However,if pesticides are used excessively,there will be certain pesticide residues in crops and related products.Therefore,it is necessary to do a good job in pesticide residue detection.The gas chromatography-mass spectrometry(GC-MS)and liquid chromatography-mass spectrometry(LC-MS)detection methods have good results and can effectively detect pesticide residues in related products.This paper reviewed and analyzed the application of GC-MS and LC-MS in pesticide residue detection,and proposed optimization measures based on practical experience,hoping to provide reference for relevant scholars.

Characterization of mulberry leaf instant tea and evaluation of its hypolipidemia effect via regulation of intestinal microbiota

The purpose of this study was to characterize mulberry leaf instant tea(MLIT)powder prepared from the'Longsang No.1'(Morus abla L.cv.Longsang 1)mulberry leaves in Heilongjiang Province(China)and assess its obesity-preventing/relieving effects.A total of 174 compounds including quercetin,chlorogenic acid,1-deoxyecomycin(1-DNJ)related to antihyperlipidemia effects were identified from the MLIT powder.MLIT treatment reversed the Lee's index,fat coefficient,and serum biochemical parameters in both the obesity relieving and obesity preventing mice fed with high-fat diet.In the obesity relieving experiment,the relative abundance of Desulfovibrio in mouse feces decreased after both 0.5%and 1%MLIT treatments.In obesity preventing experiments,mouse with different amount of MLIT treatments showed increased relative abundance of Akkermansia,Bifidobacterium and Lactobacillus,while Deferribacteres,Desulfobacterota decreased.The beneficial bacteria in the intestinal tract of mice treated with MLIT increased.This study proved that MLIT had antihyperlipidemia potential via modulating intestinal microbiota in mice.

A rapid and simple ultraperformance liquid chromatography coupled to tandem mass spectrometry(UPLC-MS/MS) method for the detection of glucuronic acid-conjugated steroid metabolites

In the present study, we effectively detected 10 steroids and glucuronic acid-conjugated steroid metabolites in 12 min by ultraperformance liquid chromatography coupled to tandem mass spectrometry （UPLC-MS/MS）. Steroids testosterone （T）, 5ct-dihydrotestosterone （DHT）, androsterone （ADT）, etiocholanolone （ETIO）, estradiol （E2） and their glucuronide conjugates were well-separated on an Eclipse Plus C18 column （2.1 mm×50 ram, RRHD 1.8μm）. The mobile phase consisted of a mixture of methanol and ultrapure water （containing I mM ammonium formate） at a ratio of 60：40 （v/v）, and the flow rate was set at 0.25 mL/min. The LC eluate was detected by electrospray ionization （ESI） source in both positive and negative ion modes. Neutral loss （NL of 176, 194, 211 and 229 Da in positive mode） and precursor ion （PI ofm/z 141,159 and 177 in positive mode and 75, 85 and 133 in negative mode） methods were applied for the detection of steroid glucuronides. The multiple reaction monitoring （MRM） transitions were m/z 289.3→97.1,291.3→105, 291.3→199.2, 273.2→145.4 and 255.2→159.1 for T, DHT, ADT, ETIO and E2 in positive mode, respectively; as well as m/z 463.3→85 for T glucuronide （T-G）, m/z 465.3→75 for DHT glucuronide （DHT-G）, ADT glucuronide （ADT-G）, ETIO glucuronide （ETIO-G） and m/z 447.3→271 for E2 glucuronide （Ez-G） in negative mode. In addition, the analytical method was also applied for the detection of steroid glucuronides in pooled human liver microsomes （HLM）, which might serve as a basis for further investigation of steroid metabolism in vivo and in vitro.

Solid and liquid state characterization of tetrahydrocurcumin using XRPD, FT-IR, DSC, TGA, LC-MS, GC-MS, and NMR and its biological activities

Tetrahydrocurcumin(THC)is one of the major metabolites of curcumin(CUR),an ancient bioactive natural polyphenolic compound.This research article describes both the solid and liquid state characterization of THC using advanced spectroscopic and thermo-analytical techniques.Anti-inflammatory,anti-oxidant,and neuroprotective activities of THC were investigated using in vitro cell lines.Liquid chromatography-mass spectrometry analysis revealed that our sample comprised 95.15%THC,0.51%tetrahydrodemethoxycurcumin(THDC),3.40%hexahydrocurcumin,and 0.94%octahydrocurcumin.Gas chromatography-mass spectrometry analysis indicated the presence of 96.68%THC and 3.32%THDC.THC in solution existed as keto-enol tautomers in three different forms at different retention time,but the enol form was found to be dominant,which was also supported by nuclear magnetic resonance analysis.THC was thermally stable up to 335.55
C.THC exhibited more suppression of cytokines(TNF-a,IL-1b,and MIP-1a)than CUR in a concentration-dependent manner in mouse splenocytes,while NK-cell and phagocytosis activity was increased in macrophages.THC showed a significant reduction of free radicals(LPO)along with improved antioxidant enzymes(SOD and catalase)and increased free radical scavenging activity against ABTSt radicals in HepG2 cells.THC displayed higher protection capability than CUR from oxidative stress and neuronal damage by improving cell viability against H2O2 induced HepG2 cells and MPPt induced SH-SY5Y cells,respectively,in a concentration-dependent manner.Thus,a variation of the biological activities of THC might rely on its keto-enol form and the presence of other THC analogs as impurities.The present study could be advantageous for further research on THC for better understanding its physicochemical properties and biological variation.

HPLC-MS/MS Determination of Oleandrin and Adynerin in Blood with Solid Phase Supported Liquid-Liquid Extraction

[Objectives]To optimize the determination method of oleandrin and adynerin in blood. [Methods]High performance liquid chromatography-mass spectrometry( HPLC-MS/MS) was applied to determine oleandrin and adynerin in blood. The blood sample was dispersed and fixed on a solid phase supported liquid-liquid extraction column and eluted with ethyl acetate. The resulting eluent was used for chromatographic separation with Kinetex C_(18) column as the separation column and gradient elution was performed using 10 mmol/L ammonium formate solution containing 0. 1%( volume fraction) formic acid and acetonitrile as the mobile phase. In the tandem mass spectrometry analysis,the detection was carried out using the electrospray positive ion source multiple reaction monitoring mode. [Results] The mass concentration of oleandrin and adynerin showed linear relationship in the range of 2-100 μg/L. The limit of detection( 3 S/N) of the method was 0. 5 μg/L.A blank sample was used as the substrate for the spike recovery test. The recovery rate was in the range of 90. 0%-98. 0%,and the relative standard deviation( RSD) of the measured values( n = 6) was in the range of 2. 1%-7. 3%. [Conclusions]The method established in this experiment has the benefits of simple pretreatment,good recovery,high sensitivity and strong specificity,and is expected to provide an ideal method for the determination of such drugs in blood.

Mass Spectrometric Structure Elucidation of the Trivalent and Pentavalent Nitrogen Contaminants of Pholcodine in the Cough Relief Medical Form Tuxidrin

In the paper “Supercritical Fluid Chromatography-Mass Spectrometry (SFC-MS) and MALDI-TOF-MS of Heterocyclic Compounds with Trivalent and Pentavalent Nitrogen in Cough Relief Medical Forms Tuxi and Cosylan” [1], the presence of morphine and other degradation products of pholcodine in cough relief medical forms of Tuxi are discussed. Tuxiis recalled from the Norwegian market by Weifa pharmaceutical company, and hence it no longer presents problems to users and health authorities there;however, the medical form Tuxidrin, which contains a significant amount of pholcodine as the active pharmacological ingredient, is still marketed. In the present paper, Tuxidrin is analyzed to determine the presence of degradation products of pholcodine. The degradation of pholcodine to morphine has been discussed previously as a factor in the development of addiction to narcotics in young persons. The structures of the contaminants in Tuxidrin, such as oxides of pholcodine, are elucidated in the present paper. The toxicity and pharmacology of oxides of alkaloids have generally not been well studied, and very little is known about the toxicity and pharmacology of the degradation (oxidation) products of pholcodine: the N-oxide and the N, N'-dioxide of pholcodine. According to Brondz and Brondz[1], the N-oxide and possibly also the N, N'-dioxide are less toxic than the original alkaloids and possess greater pharmacological activity, and hence they may be a source of useful new semisynthetic drugs. The question of possible addiction to pholcodine oxides has not been studied, and the potential of these substances to provoke allergies is unclear. The recall of Tuxi from the Norwegian marketis mainly based on the fact that pholcodine causes significantly increased levels of IgE antibodies in sensitized patients. Tuxidrin contains pholcodine and has the same negative effect as Tuxi, namely provoking allergies or even anaphylactic shock. From this point of view, Tuxidrin has no advantage over Tuxi. These two medical forms only differ in one respect: Tuxidrin requires a prescription (prescription duty medicine), but Tuxi doesnot (prescription free medicine). This aspect is also discussed in the present paper.

固相萃取法结合GC-MS/MS及UPLC-MS/MS法测定延胡索中33种禁用农药残留量

建立固相萃取法结合气相色谱-串联质谱(GC-MS/MS)及超高效液相色谱-串联质谱(UPLC-MS/MS)测定延胡索中33种禁用农药残留量的方法,并对23批来自市场的延胡索中33种禁用农药残留量进行分析。延胡索样品加乙腈提取浓缩后,分别用分散固相萃取净化管和HLB固相萃取柱净化,分别采用GC-MS/MS及UPLC-MS/MS进行检测分析。结果显示54个农药化合物在各自范围内线性关系良好,相关系数均大于0.995;三个浓度添加水平的平均加样回收率为73.3%~118.1%,RSD为0.5%~9.7%;54个农药化合物的检测下限为0.01μg·kg^(-1)~0.93μg·kg^(-1);对23批延胡索样品进行检测,共检出3种农药。本法操作简单,灵敏度高,准确性好,可用于延胡索中禁用农药多残留量的测定。

基于UPLC-Q-TOF-MS技术的脉络宁注射液酯提废渣大孔树脂富集液的化学成分鉴定和含量测定

目的利用超高效液相-四极杆串联飞行时间质谱(UPLC-Q-TOF-MS)技术分析脉络宁注射液酯提废渣的化学成分,为酯提废渣资源的再利用提供科学依据。方法利用ASD-7大孔树脂柱富集脉络宁注射液酯提废渣化学成分,采用UPLC-Q-TOF-MS技术对脉络宁注射液酯提废渣大孔树脂富集液进行数据采集和化学成分鉴定,采用定量软件对绿原酸、异绿原酸、异绿原酸C、灰毡毛忍冬皂苷甲和灰毡毛忍冬皂苷乙进行含量测定。结果共鉴定出脉络宁注射液酯提废渣中42个化学成分,包括9个酚酸类化合物、9个黄酮类化合物、10个环烯醚萜类化合物、8个三萜皂苷类化合物、5个苯丙素类化合物和1个联苄类化合物,定量分析结果显示绿原酸、异绿原酸、异绿原酸C、灰毡毛忍冬皂苷甲和灰毡毛忍冬皂苷乙在考察的浓度范围内与峰面积线性关系良好(r>0.9990),精密度、重复性和稳定性良好,加样回收率为95.38%~103.06%,RSD为0.76%~1.8%。结论本研究可用于脉络宁注射液酯提废渣大孔树脂富集液中化学成分的鉴定以及5种有效成分的准确定量分析,为脉络宁注射液酯提废渣的再利用和制备工艺奠定基础。

Insight into chemical basis of traditional Chinese medicine based on the state-of-the-art techniques of liquid chromatography-mass spectrometry

Traditional Chinese medicine(TCM) has been an indispensable source of drugs for curing various human diseases.However,the inherent chemical diversity and complexity of TCM restricted the safety and efficacy of its usage.Over the past few decades,the combination of liquid chromatography with mass spectrometry has contributed greatly to the TCM qualitative analysis.And novel approaches have been continuously introduced to improve the analytical performance,including both the data acquisition methods to generate a large and informative dataset,and the data post-processing tools to extract the structure-related MS information.Furthermore,the fast-developing computer techniques and big data analytics have markedly enriched the data processing tools,bringing benefits of high efficiency and accuracy.To provide an up-to-date review of the latest techniques on the TCM qualitative analysis,multiple data-independent acquisition methods and data-dependent acquisition methods(precursor ion list,dynamic exclusion,mass tag,precursor ion scan,neutral loss scan,and multiple reaction monitoring)and post-processing techniques(mass defect filtering,diagnostic ion filtering,neutral loss filtering,mass spectral trees similarity filter,molecular networking,statistical analysis,database matching,etc.) were summarized and categorized.Applications of each technique and integrated analytical strategies were highlighted,discussion and future perspectives were proposed as well.

Polarity-regulated derivatization-assisted LC-MS method for amino-containing metabolites profiling in gastric cancer

Amino-containing compounds,including amino acids,aliphatic amines,aromatic amines,small peptides and catecholamines,are involved in various biological processes and play vital roles in multiple metabolic pathways.Previous studies indicated that some amino-containing metabolites are significant diagnostic and prognostic biomarkers of gastric cancer.However,the discovery of precise biomarkers for the preoperative diagnosis of gastric cancer is still in an urgent need.Herein,we established a polarityregulated derivatization method coupled with liquid chromatography-mass spectrometry(LC-MS)for amino-containing metabolites profiling in the serum samples of patients with gastric cancer and healthy controls,based on our newly designed and synthesized derivatization reagent(S)-3-(1-(diisopropoxyphosphoryl)pyrrolidine-2-carboxamido)-N-hydroxysuccinimidyl ester(3-DP-NHS).Enhanced separation efficiency and detection sensitivity for amino-containing metabolites were achieved after derivatization.This method exhibited good linearity,recovery,intra-and inter-day precision and accuracy.Only 5 mL serum is needed for untargeted analysis,enabling 202 amino-containing metabolites to be detected.Statistical analysis revealed altered amino acid metabolisms in patients with gastric cancer.Furthermore,ultra high performance liquid chromatography coupled with mass spectrometry(UHPLCMS/MS)analysis quantification revealed increased serum levels of tryptamine and decreased concentrations of arginine and tryptophan in patients with gastric cancer.Receiver operating characteristic(ROC)curves indicated that an increased tryptamine/tryptophan ratio could serve as a potential biomarker for gastric cancer diagnosis.This study demostrated the possibility of using serum amino acid biomarkers for gastric cancer diagnosis,providing new avenues for the treatment of gastric cancer.

Recent progress in polar metabolite quantification in plants using liquid chromatography-mass spectrometry

Metabolite analysis or metabolomics is an important component of systems biology in the post-genomic era.Although separate liquid chromatography（LC） methods for quantification of the major classes of polar metabolites of plants have been available for decades,a single method that enables simultaneous determination of hundreds of polar metabolites is possible only with gas chromatography-mass spectrometry（GC-MS） techniques.The rapid expansion of new LC stationary phases in the market and the ready access of mass spectrometry in many laboratories provides an excellent opportunity for developing LC-MS based methods for multitarget quantification of polar metabolites.Although various LC-MS methods have been developed over the last 10 years with the aim to quantify one or more classes of polar compounds in different matrices,currently there is no consensus LC-MS method that is widely used in plant metabolomics studies.The most promising methods applicable to plant metabolite analysis will be reviewed in this paper and the major problems encountered highlighted.The aim of this review is to provide plant scientists,with limited to moderate experience in analytical chemistry,with up-to-date and simplified information regarding the current status of polar metabolite analysis using LC-MS techniques.