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[Objective] Butyrolactone I is a small molecular natural product of Aspergillus terreus with versatile bioactivities, thus the exploration of its structural diversity extension is significant. A marine-derived A. terreus strain C23-3 featuring producing butyrolactone I was used as the base strain to study the effects of butyrolactone I precursor analogs and precursor synthase inhibitors on its secondary metabolism. [Method] The strain was statically fermented under chemically regulative conditions established by seawater potato liquid medium supplied with three precursor small molecules and three 4-hydroxyphenylpyruvate synthase inhibitors. The high-performance liquid chromatography (HPLC), HPLC -ion trap mass spectrometry (MS), and MS based molecular networking together with database mining were used to further analyze the yields and diversity of secondary metabolites. [Result] The most of the precursor analogs and synthase inhibitors suppressed the synthesis of butyrolactone I to different extents. Moreover, the precursor analog 3,4-dihydroxyphenylpyruvate at a high dose, the combination of the two 4-hydroxyphenylpyruvate synthase inhibitors and the combination of these three demonstrated remarkable inhibitory effects. In addition, the global synthesis for sorts of secondary metabolites including butenoids, territrems, lovastatins, etc., was downregulated when butyrolactone I was inhibited for production. However, the yield of a cyclopeptide was upregulated by more than ten folds under this situation, which was supposed to be a stress response to the synthetic suppression of butyrolactone I as a quorum sensing molecule and inducer of global transcriptive factor lae A. The detailed mechanism deserves further investigation. [Conclusion] The present study manifests that 4-hydroxyphenylpyruvate is the precursor of butyrolactone I and reveals that 3,4-dihydroxyphenylpyruvate and 4-hydroxyphenylpyruvate synthase inhibitors can be used as small molecule tools to suppress the production of butyrolactone I, which may be applied in further study on simulated mutational biosynthesis to generate diverse butyrolactone derivatives and induce the production of cyclopeptide. [ABSTRACT FROM AUTHOR]

Objective: This study focused on the identification and activity analysis of antioxidant active peptides in walnut dregs protein hydrolysates. Methods: Protein was extracted from walnut meal by fractionation method, and five kinds of proteolytic enzymes, including trypsin, papain, neutral protease, alkaline protease and flavor protease, were used to hydrolyze the proteins. The antioxidant activity of trypsin hydrolysate （TH）, papain hydrolysate （PH）, dispase hydrolysate （DH）, alcalase hydrolysate （AH） and flavourzyme hydrolysate （FPH） were evaluated and compared. The in vitro antioxidant activity of different concentrations of AH was determined by the detection indexes of DPPH free radical scavenging rate, ABTS free radical scavenging rate and hydroxyl free radical scavenging rate. The sequences of all peptides in AH were identified by LC-MS/MS technology, and the potential antioxidant active peptides of walnut were screened by PeptideRanker, BIOPEP-UWM database and molecular docking tool AutoDock1.5.6, and the two antioxidant active peptides were obtained. The above two peptides were simulated with Keap1 protein, and the antioxidant activity of the two antioxidant peptides was analyzed by using the zebrafish embryo oxidative damage model. Results: The optimal scavenging rates of AH with better antioxidant activity among the five enzymatic hydrolysates were （71.56±0.75）%, （60.63±0.45）% and （98.63±0.06）%, respectively. LC-MS/MS was identified by computer analysis to obtain two active ALWPF and PLRWPF peptides, both of which could bind to the active sites of Keap1 protein, with binding energies of -9.2 and -9.6 kJ/mol, respectively. The safe concentrations of zebrafish embryos treated with ALWPF and PLRWPF peptides ranged from 0～50 μg/mL and 0～30 μg/mL, respectively. Conclusion: Two antioxidant peptides were obtained from walnut meal, and the antioxidant effects of them were verified by zebrafish embryo model. The results of this study can provide a basis for the in-depth utilization of walnut protein.

To study the difference in the contents of phenolics and the antioxidant activities between two kinds of Hawk tea of different maturity levels, and to evaluate their qualities, the contents of 15 phenolic compounds were determined using LC-MS/MS method. Then, the antioxidant activities of two types of tea were evaluated using DPPH radical scavenging rate, ABTS+ radical scavenging rate, and Fe3+ ferric reducing antioxidant power (FRAP). And then, the contents of 15 phenolic compounds and the antioxidant activities between two kinds of Hawk tea of different maturity levels were analyzed by analysis of variance (ANOVA). Based on the contents of 15 phenolic compounds, hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) were used to classify two kinds of Hawk tea. Finally, the contribution of different phenolic compounds in Hawk tea to antioxidation was discussed by partial least square regression analysis (PLSR). The results were as follows: (1) The contents of catechin, p-coumaric acid, isoquercitrin, hyperoside, nicotiflorin, astragalin, kaempferol, quercetin, and afzelin in tender leaf tea were significantly higher than those in old leaf tea, among which the average contents of catechin, isoquercitrin, and astragalin were higher than those in old leaf tea by 1 039.43, 169.12 and 257.35 mg·100 g-1, respectively. The results of HCA, PCA, and OPLS-DA could distinguish two kinds of Hawk tea. (2) The ANOVA showed significant differences in DPPH radical scavenging rate, ABTS+ radical scavenging rate, and FRAP between two kinds of tea, with the tender leaf tea superior to the old leaf tea. (3) The PLSR suggested that isoquercitrin, catechin, astragalin, chlorogenic acid, hyperoside, p-coumaric acid, and kaempferol were the main phenolic compounds those contributed to the antioxidant activity of Hawk tea. This study can provide a reference for Hawk tea's quality control and application promotion.

To study the difference in the contents of phenolics and the antioxidant activities between two kinds of Hawk tea of different maturity levels, and to evaluate their qualities, the contents of 15 phenolic compounds were determined using LC-MS/MS method. Then, the antioxidant activities of two types of tea were evaluated using DPPH radical scavenging rate, ABTS+ radical scavenging rate, and Fe3+ ferric reducing antioxidant power(FRAP). And then, the contents of 15 phenolic compounds and the antioxidant activities between two kinds of Hawk tea of different maturity levels were analyzed by analysis of variance(ANOVA). Based on the contents of 15 phenolic compounds, hierarchical cluster analysis(HCA), principal component analysis(PCA), and orthogonal partial least square-discriminant analysis(OPLS-DA)were used to classify two kinds of Hawk tea. Finally, the contribution of different phenolic compounds in Hawk tea to antioxidation was discussed by partial least square regression analysis(PLSR). The results were as follows:(1)The contents of catechin, p-coumaric acid, isoquercitrin, hyperoside, nicotiflorin, astragalin, kaempferol, quercetin, and afzelin in tender leaf tea were significantly higher than those in old leaf tea, among which the average contents of catechin, isoquercitrin, and astragalin were higher than those in old leaf tea by 1 039.43, 169.12 and 257.35 mg·100 g-1, respectively. The results of HCA, PCA, and OPLS-DA could distinguish two kinds of Hawk tea.(2)The ANOVA showed significant differences in DPPH radical scavenging rate, ABTS+ radical scavenging rate, and FRAP between two kinds of tea, with the tender leaf tea superior to the old leaf tea.(3)The PLSR suggested that isoquercitrin, catechin, astragalin, chlorogenic acid, hyperoside, p-coumaric acid, and kaempferol were the main phenolic compounds those contributed to the antioxidant activity of Hawk tea. This study can provide a reference for Hawk tea's quality control and application promotion. [ABSTRACT FROM AUTHOR]

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Traditional Chinese Drug Research & Clinical Pharmacology is the property of Traditional Chinese Drug Research & Clinical Pharmacology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: In this study, a one-step purification method combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) was established for the simultaneous detection of 54 veterinary drug residues belongs to 13 classes of ya-fish (Schizothorax prenati). Methods: 8 mL of 0.2% formic acid-acetonitrile:water solution (90:10, V/V) was added to 2.0 g sample and extracted by ultrasonication in an ice-water bath and cleaned up in one step by LPAS. The determination was performed on a C18 column with a gradient elution of methanol-0.1% formic acid-5 mmol/L ammonium acetate solution, dynamic multiple reaction monitoring (dMRM), positive/negative ionization mode, and quantitative LC-MS/MS by internal standard method. By adding 54 veterinary drugs, the extraction method, extraction volume, salt addition, liquid phase and mass spectrometry conditions were optimized, and the method performance (matrix effect, detection limit, quantification limit, accuracy and precision) were verified. Results: The linear relationships between the 54 drugs and their concentrations were good within the range of 0.1~50 μg/L, coefficient of determination (R2) ≥0.992. The limits of detection (LODs) were between 0.03~2.5 μg/kg and the limits of quantification (LOQs) were 0.1~8.3 μg/kg. The average recoveries of the 54 drugs at low (5~10 μg/kg), medium (10~20 μg/kg) and the high level (50 μg/kg) ranged from 70.45% to 118.1%, with relative standard deviations (RSD) between 0.01% and 9.9%. This method was applied to detect the drug in 50 samples of cultured ya-fish, and drugs were detected in seven of them. Enrofloxacin and danofloxacin were each detected twice, and sulfamethoxazole was detected four times, all at levels below the limit of quantification. Conclusion: The method was simple to operate, one-step purification, and had low limits, high sensitivity, good accuracy and precision, which met the technical requirements of multi-veterinary drug residue detection, and can provide technical support for the rapid and efficient detection of various veterinary drug residues in large quantities of ya-fish.

An analytical mehod for the determination of sanguinarine and chelerythrine in feeds by liquid chromatography tandem mass spectrometry (LC-MS/MS) method was established in this experiment. Sanguinarine and chelerythrine were extracted twice with 15 mL, 0.2% hydrochloric acid acetonitrile solution in ultrasonic water bath for 20 min. The extract was purified by HLB, and filtered through micoron filter, and analyzed by LC-MS/MS. The method was validated. The results showed that the correlation coefficient was over 0.999 in the range of 1 to 100 ng/mL; the quantitation limit was 0.005 mg/kg; recoveries were ranged from 91.9% to 101%, and RSD was ranged from 2.00% to 7.96%. This method was accurate and suitable to determine sanguinarine and chelerythrine in feeds. [ABSTRACT FROM AUTHOR]

In order to quantitate protein, a liquid chromatography-isotope dilution mass spectrometry method for the analysis of amino acids in protein hydrolysate was established. The protein was hydrolyzed at 130 ℃ in the presence of 6 mol/L hydrochloric acid solution, and separated by Hypercarb porous graphite carbon chromatography column and 0.1% perfluoropentanoic acid aqueous solution/acetonitrile mobile phase system. Five stable amino acids (proline, valine, leucine, isoleucine and phenylalanine) were selected for quantitative determination with their corresponding stable isotope markers as internal standard, and the absolute quantitative determination of protein was achieved by combining protein sequence information. The linear relationship of the five amino acids is good within the range of 10-1 000 ng/mL (R2>0.995), the limit of detection and the limit of quantification are between 0.02-0.07 ng/mL and 0.06-0.2 ng/mL, respectively. The recovery at three different levels is between 97.0%-102.4%, and the relative standard deviation is between 1.1%-3.0%. The analysis results of human IgG monoclonal antibody to nucleocapsid protein solution reference material of 2019 Novel Coronavirus and the measurement results of national metrological comparison of 2019nCovid nucleocapsid protein are satisfactory, which proves that the method has sufficient accuracy for protein determination.

Astragalus membranaceus is a traditional genuine medicinal herb with a long history of medicinal use and a wide range of distribution. The quality and therapeutic efficacy of Astragalus membranaceus from different places of origin vary greatly, and the type and content of secondary metabolites are the material basis for determining the quality of the medicinal herb. To study the differences in secondary metabolites of Astragalus membranaceus from different origins, provided an important basis for analyzing the quality formation of Astragalus membranaceus and lay a foundation for the selection and breeding of highquality Astragalus membranaceus, the experiment was conducted on three Astragalus membranaceus var. mongholicus roots from Hunyuan, Shanxi(S2-7), Wutai, Shanxi(S2-9), and Hezheng Pharmaceutical Garden, Gansu(S2-10) by LC-MS/MSbased non-targeted metabolomics, and the methods of Principal Component Analysis(PCA) and Orthogonal Partial Least Squares Discriminant Analysis(OPLS-DA) were utilized for differential metabolite screening and pathway enrichment analysis was proceeded by KEGG database. The results showed thant a total of 674 metabolites were identified and classified into 29 categories, mainly including terpenoids, flavonoids, phenylpropanoids, and alkaloids. Based on the screening of differential metabolites with P < 0.05 and Variable Importance of Projection(VIP) >1, 81 differential metabolites were screened between Astragalus membranaceus from Gansu(S2-10) and Astragalus membranaceus from Shanxi(S2-7, S2-9), and 67 differential metabolites were screened between Astragalus membranaceus from two origins of Shanxi, Wutai(S2-9) and Hunyuan(S2-7); there was a significant difference of these metabolites in terms of their contents. Enrichment analysis of the pathways showed that three metabolic pathways with significant differences(P < 0.05) were enriched in the groups of Astragalus membranaceus from Gansu and Astragalus membranaceus from Shanxi: isoquinoline alkaloid biosynthesis, indole alkaloid biosynthesis, and nicotinic acid salt and nicotinamide metabolic pathways. In conclusion, the types and contents of secondary metabolites of Astragalus membranaceus differed from different origins. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Isotopes is the property of Journal of Isotopes Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveA method involving derivatization combined with liquid chromatography-tandem mass spectrometry was developed for the determination of vitamin D in infant formula food.MethodsThe samples were treated with enzymolysis， saponification， liquid-liquid extraction， and 4-phenyl-1，2，4-triazoline-3，5-dion derivatization. Chromatographic separation was performed using an Atlantis® T3 column， and gradient elution was performed using the methanol-5 mmol/L ammonium format solution as the mobile phase. The method applied positive electrospray ionization and multiple reaction monitoring mode and was quantified with the isotope internal standard method.ResultsA good linearity was obtained with a correlation coefficient above 0.99. The average recovery levels from three different ranged from 92.3% to 94.2%， and the relative standard deviations were between 3.03% and 5.34% （n=6）. The limit of quantification was 1 μg/kg.ConclusionThis method is simple， accurate with high sensitivity and high selectivity， and suitable for the determination of vitamin D in infant formula food.

To provide scientific support for guaranteeing food safety in raw milk, a rapid method for the determination of pesticide residues in raw milk was developed using supported liquid extraction technique and ultra-performance liquid chromatography tandem mass spectrometry. The sample was precipitated with acetonitrile and then separated by high speed centrifugation. The supernatant was purified by SLE column. Separation of pesticide residues was achieved by a CORTECS C18 column. Pesticide residues were detected by ultra-performance liquid chromatography tandem mass spectrometry with electrospray ionization in the multiple reaction monitoring mode, and the quantification was accomplished by external standard method of matrix standard curve. Method validation revealed satisfactory linearities with correlation coefficients higher than 0.9962, and limits of detection and quantification for target compounds were 0.1~2.5 μg/kg and 0.3~7.5 μg/kg, the average recoveries at three spiked levels were in the range of 69.4%~113.6% with relative standard deviation (RSD, n=6) less than 8.2%. This method is simple, quickly and reliable, and shows great promise for detecting 32 different pesticide residues in raw milk.

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shenyang Pharmaceutical University is the property of Shenyang Pharmaceutical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveTo establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry （LC-MS/MS）.MethodsThe blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18， 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol （Vacetonitrile∶Vmethanol=2∶3） were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring.ResultsThe linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients （r） greater than 0.995 6. The limits of detection were 3.00， 0.40 and 1.30 ng/mL，respectively. The limit of quantitation were 8.00，1.00 and 5.00 ng/mL，respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL，respectively.ConclusionThis method has high sensitivity and good selectivity， which is suitable for the detection of carbamazepine and its metabolites in blood samples， and can be used for carbamazepine-related forensic identifications.

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A detection method for the determination of 20 kinds of cephalosporins in animal derived food was established with multiple stable isotope internal standards by liquid chromatography-tandem mass spectrometry. Cephalosporins were extracted from samples with methanol, and purified with octadecylsilane sorbent. An Ascentis C8 column was used for analyzing with 0.1% formic acid aqueous solution and acetonitrile as mobile phases. Analysis of cephalosporins were respectively performed on the positive and negative scan mode by multiple reactions monitoring. Results showed that the linear range of the methods was 5~100 μg/L for 17 kinds of cephalosporins with highly responsive, and 25~500 μg/L for 3 kinds of cephalosporins with lowly responsive. The determination coefficients of the linear equations ranged from 0.9913 to 0.9998. The limit of detection for 20 kinds of cephalosporins ranged from 1.0 to 20.0 μg/kg, and the limit of quantification ranged from 3.0 to 60.0 μg/kg in animal derived sample. The average recovery rate of 20 cephalosporins ranged from 78.08% to 115.47%, and the relative standard deviation ranged from 3.07% to 12.44%. The validated method was simple and accurate. It was suitable for the determination of 20 cephalosporins in animal food.

In order to understand the mechanism of bacterial drug resistance under the stress of quinolone antibiotics, this study took Aeromonas hydrophila as the research object, quantitative proteomics was used to compare the protein expression differences in A. hydrophila with and without enrofloxacin treatment. The results showed that total 446 differentially expressed proteins were identified by mass spectrometry, including 233 up-regulated proteins and 213 down-regulated proteins. Bioinformatics analysis showed that A. hydrophila survival may be promoted by up-regulating the expressions of most DNA repair and sulfur metabolism related proteins. Through the growth curve determination, cysteine combined with enrofloxacin can better inhibit the growth of bacteria. Meanwhile, qPCR was used to verify the expression levels of sulfur metabolism-related genes at the mRNA level, and it was uncovered that the differential expression levels of most genes at the transcription level were consistent with the protein level. These results indicate that sulfur metabolism plays an important role in the ENR stress of A. hydrophila. [ABSTRACT FROM AUTHOR]

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Forensic Medicine / Fayixue Zazhi is the property of Journal of Forensic Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveTo determine bimatoprost， tafluprost ethyl amide， latanoprost， travoprost and tafluprost in eyelash enhancing cosmetics by establishing a LC-MS/MS method.MethodsThe samples were extracted with a 50% acetonitrile water solution. A salt mixture （4 g NaCl， 1 g MgSO4） was added to the solution to induce phase separation. After centrifugation and filtration， the analysis of five prostaglandin analogs was performed with an Agilent Poroshell 120 PFP-C18 （2.7 μm， 2.1 mm×100 mm） column， using 0.02% formic acid containing 5 mmol·L-1 Acetic acid amine and acetonitrile by gradient elution at a flow rate of 0.5 mL·min-1. The analytes were detected with electrospray ionization source in positive ion mode （ESI+） and multiple reaction monitoring （MRM）， and quantified by external standard curve.ResultsThe results showed that it had a good linearity in the range of locatable ambit of concentration with correlation coefficients （r） larger than 0.999. The detection limit of five prostaglandin analogs （LOD） was 0.000 2‒1.5 μg·g-1. The spiked recoveries were 93.2% to 103.5% with a relative standard deviation （RSD） of 1.2% to 3.4%.ConclusionThe method is simple， rapid and highly sensitive. It is suitable for the determination of five prostaglandin analogs in eyelash enhancing cosmetics.

The short- and long-term stability of multi-component mixtures and intermediate mixtures of analytical standards of veterinary drugs, which can potentially occur in food and feed chains, was examined by an isochronous measurement approach. Short-term stability testing of calibrants included storage for 1, 2,4, and 7 days at -20 ℃ (as a baseline) 4 ℃, and 23 ℃ (with and without exposure to sunlight), respectively.Long-term stability testing conditions of intermediate mixes were -20 ℃, 4 ℃, 23 ℃ (with and without exposure to sunlight), and control temperature at -80 ℃ while the testing period was 2, 4, 8, and 12 weeks,respectively. Results indicated that calibration standards should ideally be stored at 4 ℃ for only 1～2 days,without the presence of acid. Neutral storage conditions were acceptable even at room temperature. Storage of intermediate mixtures containing ß-lactams and cephalosporins for longer than 1 month under 4 ℃ and room temperature resulted in a loss of almost 90%. When it comes to the intermediate mixtures with penicillin V and G, acceptable storage conditions were 2 weeks at -20 ℃, without the presence of acid. Other classes of veterinary drugs were less critical as considers long-term stability. Overall, storage conditions at -20 ℃were considered optimal for long-term storage of intermediate mixes of veterinary drug standards.

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective　To develop a LC-MS/MS method for the determination of scopolamine and atropine in human blood and urine after Datura stramonium poisoning. Methods　 Shim-pack GISR-HP C18 column was used for gradient elution with acetonitrile formic acid （0.1%） as the mobile phase. The electrospray ionization ion source multiple reaction monitoring mode mass spectrometry was used to analyze the scopolamine and atropine by two characteristic ion pairs and the external standard curve method. Results　The quantitative ion pairs of scopolamine and atropine were m/z 304.25 [M+H]+→138.15 and m/z 290.2 [M+H]+→124.15，respectively. The linear range of scopolamine and atropine were 1～100 ng/mL （R≥0.999）. The limits of detection （LOD） were 0.45 ng/ml and 0.19 ng/ml in blood，0.38 ng/ml and 0.16 ng/ml in urine；The limits of quantitation （LOQ） were 1.01 ng/ml and 0.63 ng/ml in blood，1.07 ng/ml and 0.38 ng/ml in urine；The extraction recoveries were 94.38% and 94.49% in blood， 94.96% and 96.52% in urine； The average recoveries of the substances were 94.38% and 94.49% in matrixs. The matrix effects effect was -3.51%～0.84%. The accuracy of substances were 89.38%～102.86%，and the intra day and inter day precisions were less than 6%. Conclusions　The method can be used to determine the concentration of scopolamine and atropine in biological samples quickly and accurately. [ABSTRACT FROM AUTHOR]

Objective：A high performance liquid chromatography mass spectrometry （LC ⁃ MS） method was established to simultaneously quantify the lenalidomide，vorinostat and dexamethasone in rat plasma. The method was successfully applied to the plasma pharmacokinetics of lenalidomide，vorinostat and dexamethasone after oral administration to rats. Methods：The LC column was Agilent Zorbax Eclipse Plus C18（100 mm ×2.1 mm，1.8 μm）. The mobile phase was comprised of acetonitrile and water containing 0.1% formic acid+5 mmol/L ammonium acetate. The gradient profile was used. Flow rate was 0.6 mL/min. Column temperature was 35 ℃. Sample injection volume was 5 μL. The quantification was obtained by scanning with multiple reaction monitoring（MRM）via the positive electrospray ionization（ESI + ） source. Results：The correlation coefficients of the lenalidomide，vorinostat and dexamethasone，respectively were over 0.995. The relative standard deviation（RSD）values of the inter⁃ and intra⁃ precisions were less than 7.4%. The accuracy ranged from 94.7% to 106.7%. The matrix effect values were sufficiently minimized to 92.3%~109.7%. The average recoveries from rat plasma were 87.4% to 103.6%. Conclusion：The validated method is further applied to the determination of lenalidomide，vorinostat and dexamethasone in plasma. The method is rapid and economical，and can provide helpful information for pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Uncertainty assessment of the content of synthetic capsaicin, natural capsaicin and dihydrocapsaicin in edible oils and fats by liquid chromatography-mass spectrometry was carried out, and the sources of uncertainty and the key factors affecting the test results were analyzed, so as to improve the accuracy of test results. Methods: To establish a mathematical model for the uncertainty of the content of synthetic capsaicin, natural capsaicin and dihydrocapsaicin in edible oils and fats, to analyze the factors that may introduce uncertainty in the detection process, and to evaluate each uncertainty component. Results: The contents of synthetic capsaicin, natural capsaicin and dihydrocapsaicin in edible oil were （0.250±0.032）, （0.123±0.015）, （0.130±0.014） μg/kg, k=2. Conclusion: This uncertainty is mainly derived from the linear fitting of the standard curve and the uncertainty introduced by the analysis of liquid chromatography-mass spectrometry.

In order to analyze the differences of metabolites and their pathways from flowering to withering of Rhododendron delavayi, we used LC-MS/MS material separation and identification technique to non-targeted the chemical components of bud stage, dehiscence stage, pollination stage, blooming stage, senescence stage and withering stage. The results were as follows:(1)A total of 973 kinds of metabolites were detected, mainly including flavonoids, organic acids, phenolic acids, amino acids and their derivatives, lipids, alkaloids and so on.(2)Principal component analysis(PCA)showed that there were differences in metabolites among samples. Combined with orthogonal partial least squares discriminant analysis(OPLS-DA), P value of t-test and fold change of univariate analysis, differential metabolites(VIP > 1, P < 0.05, Fc > 2 or Fc < 0.5)were screened out, involving 591 species, the quantity and expression of differential metabolites increased significantly after the R. delavayi flower stage entered the senescence stage and the withering stage, in which the expression of differential metabolites from bud stage to dehiscence stage was mainly down-regulated, while those after entering senescence stage and withering stage were mainly up-regulated.(3)A total of 68 differential metabolic pathways were annotated by KEGG, of which three pathways were significantly enriched with differential metabolites(P < 0.01), including phenylpropanoids biosynthesis, plant hormone biosynthesis and flavonoid biosynthesis.(4)Based on the analysis of biosynthetic pathways of phenylpropanoids, flavonoids and other effective components, ten kinds of differential metabolites were screened from flowering to withering of R. delavayi, including L-phenylalanine, trans-cinnamic acid, chalcone, naringenin, p-coumaroyl shikimic acid, ferulic acid, coniferyl alcohol, sinapic acid, syringin and quercetin. In addition, the differential metabolites of effective components showed that phenylpropanoids biosynthesis and metabolism activities gradually increased with the development of R. delavayi, while flavonoid biosynthesis gradually decreased. These key differential metabolites may play an important role in regulating the development of R. delavayi. This study provides a metabonomic basis for the study of effective components in the metabolic pathway during the process from flowering to withering of R. delavayi, and provides a reference for the further study of the molecular mechanism of flowering period regulation of R. delavayi. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To develop a liquid chromatography with tandem mass spectrometry (LC-MS/MS) to simultaneously detect the activities of 9 CYP450 enzymes in human liver microsomes in order to anticipate the possibility of drug-drug interactions. Methods Nine different enzyme substrates were used as probes to incubate with human liver microsomes, with nifedipine as internal standard. All metabolites were eluted by Agilent 1290 series liquid chromatograph and then analyzed under multiple reaction monitoring. The IC50 values obtained by single substrate method and cocktail mixed substrate method were compared. Results Our established method had good specificity, and all the chromatographic peaks were completely separated without interference. The linear relationship was good. The correlation coefficients of 9 metabolites within the range of the standard curve were all greater than 0.99. The accuracy of the method was 85.34%~113.89%, the intra-day relative standard deviation (RSD) was < 12.49%, and the inter-day RSD was < 14.98%, which complied with the relevant standards. The IC50 value of the inhibitor determined by this cocktail method was highly correlated with that of a single probe substrate (R2> 0.997 8). Conclusion Our LC-MS/MS method can quickly and simultaneously measure the activities of 9 CYP450 enzymes in human liver microsomes.

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The short- and long-term stability of multi-component mixtures and intermediate mixtures of analytical standards of veterinary drugs, which can potentially occur in food and feed chains, was examined by an isochronous measurement approach. Short-term stability testing of calibrants included storage for 1, 2, 4, and 7 days at --20 (as a baseline) 4, and 23 °C (with and without exposure to sunlight), respectively. Long-term stability testing conditions of intermediate mixes were --20 °, 4 °C, 23 °C (with and without exposure to sunlight), and control temperature at --80 °C while the testing period was 2, 4, 8, and 12 weeks, respectively. Results indicated that calibration standards should ideally be stored at 4 °C for only 1-2 days, without the presence of acid. Neutral storage conditions were acceptable even at room temperature. Storage of intermediate mixtures containing ß-lactams and cephalosporins for longer than 1 month under 4 °C and room temperature resulted in a loss of almost 90%. When it comes to the intermediate mixtures with penicillin V and G, acceptable storage conditions were 2 weeks at --20 °C, without the presence of acid. Other classes of veterinary drugs were less critical as considers long-term stability. Overall, storage conditions at --20 °C were considered optimal for long-term storage of intermediate mixes of veterinary drug standards. [ABSTRACT FROM AUTHOR]

Copyright of Detergent & Cosmetics is the property of Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

N-linked glycosylation, as one of the most common post-translation modification in proteins, is modified on asparagine residue among the N-X-T/S/C(X≠P) motif. N-glycans share a common core structure consisting of two N-acetylglusosamines and three mannoses, and which have three common types of high-mannose, hybrid and complex. N-glycosylation sites have both macro- and micro- heterogeneities and the function of each N-glycoylation is both site- and structure-specific. The precise site- and structure-specific identification and quantification of N-glycosylation is the main road of discovering disease diagnostic and prognostic biomarkers as well as drug targets. With the advancements in high-efficient enrichment materials, liquid chromatography separation technology, cascade mass spectrometry dissociation and detection technologies and bioinformatics database search methods, N-glycoproteomics enables high-throughput site- and structure-specific identification and quantification of N-glycosylation in complex systems. This paper mainly reviewed the basic procedures in the N-glycoproteomics pipeline including sample preparation, high-performance LC-MS/MS analysis and bioinformatics data processing as well as representative applications. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Surfactant Detergent & Cosmetics (1001-1803) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Japanese Journal of Food Chemistry & Safety is the property of Japanese Society of Food Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Japanese Journal of Food Chemistry & Safety is the property of Japanese Society of Food Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A method for determination of tomatine in tomatoes and tomato products was developed using LC-MS/MS. Tomatine was extracted from these samples with 20% methanol aqueous solution containing 1% acetic acid. Cleanup was performed on sample solutions using a polymer-based OASIS HLB cartridge column. LC separations were performed using an Inertsil ODS-3 column and a linear gradient elution using 0.1% formic acid aqueous solution and 0.1% formic acid in acetonitrile as the mobile phase. Detection of MS was performed in positive ion electrospray ionization mode. The range of average recoveries of tomatine from 4 fresh tomatoes and 7 processed tomato products added with 0.01 mg/100 g were 80.3-94.8% and 76.8-95.5%, respectively. The limit of quantitation was estimated to be 0.01 mg/100 g, considering the limit of bitter stimulus. Using the present method, results of tomatine content in two tomatoes tasted bitter by consumers, were 1.04 mg/100 g and 1.54 mg/100 g. Further, results of a field survey of tomatine content in commercially available fresh tomatoes and processed tomato products were in the range of 0.01 mg/100 g to 3.05 mg/100 g. In addition, when tomatine was added to tomato and then heat-treated, no significant change of tomatine amount was observed by heating. [ABSTRACT FROM AUTHOR]

Objective To develop liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the content determination of voriconazole (VRCZ) and its N-oxide (VNO) in human plasma, and to apply it to clinical samples. Methods Ketoconazole was used as the internal standard (IS). The plasma samples were treated with methanol to precipitate protein and analyzed by HPLC-MS/MS. The detection was accomplished with electrospray ionization (ESI) operated in positive ionization mode, and ion reaction pairs were selected to be m/z350.1→m/z127.0 (VRCZ), m/z366.1→m/z224.0 (VNO) and m/z531.0→m/z82.1 (Ketoconazole). Chromatographic separation had been achieved on Inertsil ODS-3 (50/2.1) with methanol-10 mmol/L ammonium acetate (90:10) as the mobile phase. Plasma concentrations of VRCZ and VNO in 23 patients were determined. Results Both VRCZ and VNO were linear (r>0.999) over the concentration ranges of 0.4~10.0 μg/mL, inter- and intra-batch relative standard deviations (RSDs) and matrix effect were all less than 15%. The 2 compounds remained stable during sample storage and handling progress. Plasma concentrations of VRCZ in 23 patients ranged from 0.4 to 14.3 μg/mL, and those of VNO ranged from 0.5 to 7.2 μg/mL. Significant variance was found among these patients. Conclusion LC-MS/MS is simple, quick and sensitive for detection of VRCZ and VNO, and can be used for drug monitoring in clinical practice.

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)