Determination of urine catecholamines and metanephrines by reversed-phase liquid chromatography-tandem mass spectrometry

The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.

Determination of egg and milk allergen in food products by liquid chromatography-tandem mass spectrometry based on signature peptides and isotope-labeled internal standard

The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.

Simultaneous Determination of 14 β-Receptor Agonists Residues in Mutton by High Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS)

[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-glucuronidase and extracted with 5%acetic acid-acetonitrile(1:99,V/V)solution.An Eclipse plus C 18 column was used for separation,and the MRM mode was used for qualitative analysis,and the external standard method was used for quantitative analysis of matrix standard solutions.[Results]Under the optimal conditions,the retention time of the 14 kinds ofβ-receptor agonists ranged from 1.0 to 9.5 min.When the mass concentration was in the range of 0.05-0.50μg/ml,the linear relationship ofβ-receptor agonists was good,with correlation coefficients(r)≥0.9992.The detection limits of the method were in the range of 0.04-0.87μg/kg,and the quantitative limits were in the range of 0.35-1.86μg/kg.The average recovery values were in the range of 82.8%-108.9%,with RSDs(n=6)in the range of 1.9%-6.7%.[Conclusions]The method is simple,sensitive,reproducible,accurate,and can be used for simultaneous determination of the 14 kinds ofβ-receptor agonist residues in mutton.

Simultaneous determination of 15 pesticide residues in Chinese cabbage and cucumber by liquid chromatography-tandem mass spectrometry utilizing online turbulent flow chromatography

In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.

Simultaneous Determination of Bisphenols and Alkylphenols in Water by Solid Phase Extraction and Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

To establish an analytical method for determination of four bisphenols （BPA, BPB, BPF, and BPS） and two alkylphenols （4-n-OP, 4-n-NP） in water by ultra performance liquid chromatography- tandem mass spectrometry （UPLC/MS/MS）. The water samples were extracted and condensed with solid-phase extraction （SPE） using C18 cartridges and eluted by acetonitrile. Separation was carried out with Acquity BEH C8 column and detection were performed by UPLC/MS/MS. Quantification was calculated by using the internal standard BPA-d16 and 4-n-NP-d8. The linear correlation coefficients of these compounds in the range of 1.0-100.0μg/L were all over 0.999. The minimum detectable concentrations were 0.75-1.0 ng/L, and the recoveries ranged from 87.0% to 106.9%.

Development of a Liquid Chromatography-tandem Mass Spectrometry Method for Determination of Butoconazole Nitrate in Human Plasma and Its Application to a Pharmacokinetic Study

Summary： A liquid chromatography-tandem mass spectrometry （LC-MS/MS） method was developed and validated for the determination of butoconazole in human plasma. Human plasma samples of 0.2 μL were pretreated by a single step protein precipitation procedure and analyzed using a high performance liquid chromatography （HPLC） electrospray tandem mass spectrometer system. The compounds were eluted isocratically on an Inertsil ODS-SP column （100 min×2.1 mm, 3 μm）, ionized using a positive ion atmospheric pressure electrospray ionization source and analyzed using multiple reaction monitoring （MRM） mode. The ion transitions monitored were m/z 412.8→q65.1 for butoconazole and m/z 453.4→230.3 for the internal standard. The chromatographic run time was 3.5 min per injection, with retention time of 2.47 rain and 2.15 min for butoconazole and repaglinide, respectively. The method was validated to be linear over the range of 20 to 8000 pg/mL （r〉0.999） by using a weighted （1/x2） quadratic regression. The mean recovery rate was more than 86.7%, and the intra- and inter-day precision of the quality control samples （QCs） was less than 8.3% and the accuracy ranged from 96.0% to 110.2%, which indicated that the quantitative method was reliable and accurate. The method is simple, rapid, and has been applied successfully to a pharmacokinetics study of butoconazole nitrate suppositories in healthy Chinese females.

Application of Liquid Chromatography-Tandem Mass Spectrometry in Determination of Veterinary Drug Residues

With the long -term and irrational use of veterinary drugs and drug additives in the process of animal feeding, the veterinary drug resi- dues in animals and their additives can be ingested into the human body and pose potential threat to human health. Detection of veterinary drug resi- dues are extremely important practical significance to protect the ecological environment and human health. In recent years, liquid chromatography -tandem mass spectrometry has been widely used in vetednary drug residue detection because of its applicability, qualitative and quantitative fea- tures as well as high sensitivity. This article summarized the application of liquid chromatography -tandem mass spectrometry in detection veterinary drug residues from feed, animal products, arid udne as well as illicit drugs and harmful additives.

Liquid Chromatography-Tandem Mass Spectrometry Assay to Detect Ethyl Glucuronide in Human Fingernail: Comparison to Hair and Gender Differences

Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alterna-tive to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P < 0.01, n = 529). Evaluating each gender separately revealed that the correlation of male fingernail to male hair was large and significant (r = 0.782, P < 0.01, n = 195) while female hair to female fingernail was small yet sig-nificant (r = 0.249, P < 0.01, n = 334). The study results demonstrated that fingernail may be a suitable alternative to hair for ethyl glucuronide detection and may be the preferred sample type due to the lack of a gender bias.

Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

An accurate and sensitive method for the simultaneous determination of gibberellic acid（GA3）, gibberellin A4（GA4） and gibberellin A7（GA7） residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry（LC-MS/MS） with electrospray ionization based stable isotope dilution analysis（SIDA）. The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance（HLB） solid phase extraction（SPE） column was tested for the capacity of the cleanup of the tomato paste in compared with C18 SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA3, GA4 and GA7 were 42.6%―75.0% in external standard method（ESM） and 91.1%―103.8% in internal standard method（ISM） respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection（2 ng/g for GA3 and GA4, 0.3 ng/g for GA7）, excellent linear dynamic ranges（5―500 ng/g for GA3 and GA4, 1―100 ng/g for GA7） and good relative standard deviation ranges（4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test）.

Determination of thyreostats in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry

Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)in positive electrospray ionization mode.Extraction and clean-up were achieved using a ChemElut cartridge with tert-butyl methyl ether,without a derivatization step.Separation was achieved on an Acquity UPLC SS T3 column.The mobile phase was acetonitrile and water containing 0.2%(v/v)formic acid.The mass spectrometer was operated in multiple reaction monitoring mode.Urine samples were spiked with TS solution at levels corresponding to 5,10,15,and 20μg/L.The accuracy(internal standard corrected)ranged from 92%to 107%,with a repeatability precision(relative standard deviation,RSD)less than 15%for all five analytes.The RSDs within-laboratory reproducibility was less than 26%.The decision limits(CCα)and detection capabilities(CCβ)were obtained from a calibration curve and were in the ranges of 3.1-6.1μg/L and 4.0-7.4μg/L,respectively.The CCαand CCβvalues were below the recommended concentration,which was set at 10μg/L.The results show that the described method is suitable for the direct detection of TSs in bovine urine.This method can also be used to determine TSs in porcine urine.

Rapid quantification of the metabolite of valacyclovir hydrochloride in human plasma by liquid chromatography-tandem mass spectrometry

Objective To establish a rapid,sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of acyclovir (the metabolite of valacyclovir hydrochloride) in human plasma. Methods After addition of ganciclovir as internal standard (IS),plasma samples were prepared by one-step protein precipitation using acetonitrile as precipitant,followed by an isocratic elution with 0.1% formic acid solution-methanol (95∶5,v/v) on an Agilent ZORBAX SB-C18 (150mm×2.1mm i.d.,3.5μm) column. Detection was performed on a triple-quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 226.2→152.1 for acyclovir and m/z 256.2→152.1 for the IS. Results The analytical results demonstrated a good linearity over the ranges from 0.005 to 4μg/mL (r=0.9999) for valacyclovir hydrochloride. The relative standard deviations (RSD) of intra-batch and inter-batch were less than 4.06% and 9.23%,respectively. The limit of detection and lower limit of quantification in human plasma were 2ng/mL and 5ng/mL,respectively. Conclusion The method was simple,sensitive,accurate and reproducible and has been successfully applied to a bioequivalence study of valacyclovir hydrochloride capsules in Chinese healthy male volunteers.

Rapid and Sensitive Liquid Chromatography-Tandem Mass Spectrometry for Quantification of Glycyrrhetic Acid in Human Plasma

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry（LC-MS/MS） for the determination of glycyrrhetic acid in human plasma with ginsenoside Rh2 as internal standard was developed and validated. The plasma samples were prepared via liquid-liquid extraction with ethyl acetate. Chromatographic separation was accomplished on a Venusil MP-C18（50 mm×2.1 mm, 5 μm i.d.） column at 25 °C. The mobile phase consisted of acetonitrile/5 mmol？L-1 ammonium acetate（10：90, volume ratio） at a flow rate of 0.4 mL/min. Negative electrospray ionization was utilized as the ionization source. Glycyrrhetic acid and internal standard were determined via the mutiple reaction monitoring of precursor→production ion transitions at m/z 469→425, 409 and m/z 621→161, respectively. Each sample was chromatographed within 2.5 min. The lower limit of quantification was 0.50 ng/mL for 200 μL of plasma sample and the linear range was from 0.50 ng/mL to 800 ng/mL. The intra- and inter-day precisions were less than 8.76% in terms of relative standard deviation（RSD）, and the accuracy was within a range of -3.25%-1.32% in terms of relative error（RE）. The method was successfully applied to the pharmacokinetic studies of glycyrrhetic acid in healthy male Chinese volunteers after a single oral administration of 75 mg of glycyrrhizin.

Rapid Determination of Three Kinds of Microcystins in Environmental Water Samples by Disk SPE-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.

Determination of Sodium Pentachlorophenoxide Residues in Animal-derived Foods by Ultra-performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS)

[Objectives]This study was conducted to establish an ultra-high performance liquid chromatography-tandem mass spectrometry for the rapid extraction of sodium pentachlorophenoxide from animal-derived food.[Methods]The samples were extracted with an acetonitrile water solution(8∶2),0.1 mol/L hydrochloric acid and a purification extraction bag with shaking.Centrifugation was performed to obtain supernatants,which were added to purification tubes containing PSA and C_(18) for purification,and then filtered with membranes for determination.Each test solution was separated by a ZORBAX Eclipse plus C_(18) column with acetonitrile and 5 mmol/L ammonium acetate as mobile phases,and determined with electrospray ionization and multiple reaction monitoring.[Results]The method had good linearity in the concentration range of 1.0-50 ng/ml,and the correlation coefficient was 0.9997.The limit of detection was 0.25μg/kg and the limit of quantification was 0.75μg/kg.The recovery was between 87.4%and 112.5%,and the RSD%was between 0.5%and 10.0%.[Conclusions]The method has simple operation and high sensitivity,and is suitable for trace detection of sodium pentachlorophenoxide in large quantities of animal-derived food.

An Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry Method for the Quantification of Vancomycin Requiring Only 2 μL of Rabbit Serum

A highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantification of vancomycin (VAN) in low volumes of rabbit serum. For each analysis, 2 μL rabbit serum was precipitated with methanol that contained the internal standard teicoplanin (TEI). The supernatant was transferred into a 384 well-plate, diluted with water, covered with a pierceable silicone mat and 5 μL was analyzed in positive ionization mode. The UHPLC-MS/MS consisted of an Agilent 1290 Infinity UHPLC system connected to an AB Sciex QTrap&reg;5500 hybrid linear ion-trap triple quadrupole mass spectrometer equipped with a Turbo Spray source. Chromatographic separation was achieved using a Waters Acquity UPLC BEH C18 (1.7 μm, 2.1 mm × 100 mm) column, a VanGuard (1.7 μm, 2.1 × 5 mm) guard column and a mobile phase of water and methanol both containing 5 mM ammonium acetate with 0.1% formic acid. VAN was quantified with multiple reaction monitoring using the transitions of m/z 725.5/144.2, and TEI was monitored at m/z 940.6/316.4. The accuracy, precision, linearity, range and lower limit of quantification (LLOQ) were determined. The accuracy was ≤9.93% and the precision was ≤10.6%. The range was established as 0.1 to 40 μg·mL-1. The LLOQ was 0.1 μg·mL-1 VAN requiring 2 μL of sample with an accuracy of -20.2% and precision of 8.39%. The method was applied successfully to determine the VAN concentrations in rabbit serum after the i.v. administration of VAN via implanted ear catheters.

A liquid chromatography with tandem mass spectrometry method for quantitating total and unbound ceritinib in patient plasma and brain tumor

A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a secondgeneration ALK inhibitor, in patient plasma and brain tumor tissue samples. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C_(18) column using a 4-min gradient elution consisting of mobile phase A(0.1% formic acid in water) and mobile phase B(0.1% formic acid in acetonitrile), at a flow rate of 0.4 m L/min. Ceritinib and the internal standard([^(13)C_6]ceritinib) were monitored using multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantitation(LLOQ) was 1 n M of ceritinib in plasma. The calibration curve was linear over ceritinib concentration range of 1–2000 n M in plasma. The intra-and interday precision and accuracy were within the generally accepted criteria for bioanalytical method( o15%).The method was successfully applied to assess ceritinib brain tumor penetration, as assessed by the unbound drug brain concentration to unbound drug plasma concentration ratio, in patients with brain tumors.

Determination of okadaic acid related toxins from shellfish (<i>sinonovacula constricta</i>) by high performance liquid chromatography tandem mass spectrometry

Consumption of shellfish contaminated with algal toxins produced by marine dinoflagellates can lead to diarrhetic shellfish poisoning (DSP). It was therefore essential that there are analytical techniques to identify and quantify DSP toxins in shellfish. This new methodology could facilitate DSP monitoring and create a means of rapidly responding to incidents threatening public health. In the last years there were different analytical methods for DSP, such as mouse bioassay and LC-FLD. With the development of instrument, Liquid chromatography-mass spectrometry was substituted for other analytical methods with its good sensitivity and selectivity and without derivatization for the determination of DSP. In this report, a high performance liquid chromatogra-phytandem mass spectrometric(HPLC-MS/MS)method was developed for the simultaneous determination of okadaic acid (OA) and dinophysistoxins(DTX1) in Sinonovacula constricta. Optimization of pretreatment experiment was carried out to maximize recoveries and the effectiveness. The analytes were determined under multi-reactions monitoring (MRM) scan type with tandem mass analyzer using negative ion electrospray ionization (-ESI) mode .Finally, the detection and identification of OA and DTX-1 were based upon their retention times (RT) and the fragmentation patterns of their mass spectra. The method of LOQ for the two poisons was 0.02 mg·kg-1.The real sample test showed that this method could be used for sensitive, fast, and accurate determination of the two diarrheic shellfish poisons in shellfish.

Analysis of proteomic differences between liquefied aftercataracts and normal lenses using two-dimensional gel electrophoresis and mass spectrometry

AIM：To analyze and identify the proteomic differences between liquefied after-cataracts and normal lenses by means of liquefied chromatography-tandem mass spectrometry（LC-MS/MS）.METHODS：Three normal lenses and three liquefied after-cataracts were exposed to depolymerizing reagents to extract the total proteins.Protein concentrations were separated using two-dimensional gel electrophoresis（2-DE）.The digitized images obtained with a GS-800 scanner were then analyzed with PDQuest7.0 software to detect the differentially-expressed protein spots.These protein spots were cut from the gel using a proteome work spot cutter and subjected to in-gel digestion with trypsin.The digested peptide separation was conducted by LC-MS/MS.RESULTS：The 2-DE maps showed that lens proteins were in a p H range of 3-10 with a relative molecular weight of21-70 kD.The relative molecular weight of the more abundant proteins was localized at 25-50 kD,and the isoelectric points were found to lie between PI 4-9.The maps also showed that the protein level within the liquefied after-cataracts was at 29 points and significantly lower than in normal lenses.The 29 points were identified by LC-MS/MS,and ten of these proteins were identified by mass spectrometry and database queries：beta-crystallin B1,glyceraldehyde-3-phosphate dehydrogenase,carbonyl reductase（NADPH）1,c DNA FLJ55253,gamma-crystallin D,GAS2-like protein 3,sorbitol dehydrogenase,DNA FLJ60282,phosphoglycerate kinase,and filensin.CONCLUSION：The level of the ten proteins may play an important role in the development of liquefied aftercataracts.

Determination of icariside,hyperoside and psoralen in food by liquid chromatography-tandem mass spectrometry

A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was built to determine icarside,hyperoside and psoralen in food.The samples were extracted with 70%methanol,the solid and semi-solid hotpot seasoning samples were purified by solid phase extraction column,and then determined by HPLC-MS/MS.Acetonitrile and 0.1%formic acid solution were used as the mobile phase,and the gradient elution was adopted for analysis.As shown in the results,the analytes had good linearity in the range of 0.05−100 ng/mL,and the correlation coeffificients(R^(2))were greater than 0.999.In this method,the limits of quantitation(LOQ)of psoralen,icariside and hyperoside in liquid samples were 1.25,25.0 and 12.5μg/L respectively;while the LOQs of psoralen,icariside and hyperoside in solid samples and hotpot seasoning samples were 1.25,25.0 and 12.5μg/kg,respectively.The liquid beverage,solid beverage,health food(in the form of oral liquid,capsule,tablet),integrated alcoholic beverage and solid hotpot seasoning were selected as representative samples and used for method validation.The average spiked recoveries at 3 levels(LOQ,2 LOQ,10 LOQ)were in the range of 83.7%−115.0%,and the relative standard deviations were in range of 0.5%−9.4%(n=6).The method is rapid,accurate and sensitive,which is suitable for the simultaneous determination of icariside,hyperoside and psoralen in different food matrices.

Serum proteins differentially expressed in gestational diabetes mellitus assessed using isobaric tag for relative and absolute quantitation proteomics

BACKGROUND As a well-known fact to the public,gestational diabetes mellitus(GDM)could bring serious risks for both pregnant women and infants.During this important investigation into the linkage between GDM patients and their altered expression in the serum,proteomics techniques were deployed to detect the differentially expressed proteins(DEPs)of in the serum of GDM patients to further explore its pathogenesis,and find out possible biomarkers to forecast GDM occurrence.METHODS Subjects were divided into GDM and normal control groups according to the IADPSG diagnostic criteria.Serum samples were randomly selected from four cases in each group at 24-28 wk of gestation,and the blood samples were identified by applying iTRAQ technology combined with liquid chromatography-tandem mass spectrometry.Key proteins and signaling pathways associated with GDM were identified by bioinformatics analysis,and the expression of key proteins in serum from 12 wk to 16 wk of gestation was further verified using enzyme-linked immunosorbent assay (ELISA).RESULTS Forty-seven proteins were significantly differentially expressed by analyzing the serum samples between the GDMgravidas as well as the healthy ones. Among them, 31 proteins were found to be upregulated notably and the rest16 proteins were downregulated remarkably. Bioinformatic data report revealed abnormal expression of proteinsassociated with lipid metabolism, coagulation cascade activation, complement system and inflammatory responsein the GDM group. ELISA results showed that the contents of RBP4, as well as ANGPTL8, increased in the serumof GDM gravidas compared with the healthy ones, and this change was found to initiate from 12 wk to 16 wk ofgestation.CONCLUSION GDM symptoms may involve abnormalities in lipid metabolism, coagulation cascade activation, complementsystem and inflammatory response. RBP4 and ANGPTL8 are expected to be early predictors of GDM.