Simultaneous determination of eight carbapenems in milk by modified QuEChERS and ultra high performance liquid chromatography coupled with high-field quadrupole-orbitrap high-resolution mass spectrometry.

A simple and accurate method of ultra high performance liquid chromatography (UHPLC) coupled with quadrupole-high field Orbitrap high-resolution mass spectrometry (QE HF HRMS) has been developed for analyzing 8 trace-level (µg/L) carbapenems in milk. Mass spectrometry conditions, chromatographic conditions, extraction solvent and QuEChERS procedures were optimized for determination of 8 carbapenems in milk. Samples were extracted and purified by modified QuEChERS procedure. Good separation for 8 carbapenems s was achieved with a PFP column at 8 min. Method validation results showed the linear ranges are 1-100 µg/L to 10-1,000 µg/L, the correlation coefficients are more than 0.995, and the recoveries of spiked samples are 79.3%-104% with a relative standard deviation less than 15%. This method successfully applied to monitor residue of carbapenems in real milk, four kinds of carbapenems have been detected in 8 sample of 79 collected milks with concentration ranged between 15 µg/L∼3,325 µg/L.

Trace analysis of progesterone and 21 progestins in milk by ultra-performance liquid chromatography coupled with high-field quadrupole-orbitrap high-resolution mass spectrometry.

A method for rapid screening and quantification of progesterone and progestins in milks by ultrahigh-performance liquid chromatography coupled with quadrupole-high field Orbitrap high-resolution mass spectrometry (UHPLC QE HF HRMS) was established. Milks samples were extracted by acetonitrile + hexane (80 + 20), purified by prime HLB SPE and analyzed by UHPLC QE HF HRMS. The detection limit of progesterone and 21 progestins in milk is between 0.05 µg/kg -0.3 µg /kg, the correlation coefficient of progesterone and progestins in the corresponding concentration range is more than 0.99, recoveries for milk samples are between 80.7% and 108.3% with the relative deviation is less than 15%.The method fulfils the requirements of veterinary drug residue detection validation of EU and China, and successfully applied to detecting the µg/kg level of progesterone and monitoring residual of progestins in real milk.

Application and problems of quinoline alkaloids in the treatment of COVID-19 / 西安交通大学学报(医学版)

The febrile respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the focus of global attention. Up to now, the infection has been continuing to spread all over the world and it is urgent to develop specific drugs for SARS-CoV-2. Finding effective and safe drugs which are already available in the market for treating coronavirus disease 2019 (COVID-19) is one of the main strategies to solve the problem in time. As quinoline alkaloids against malaria, chloroquine and hydroxychloroquine have been proved to have the anti-SARS-CoV-2 activity. Quinoline alkaloids are expected to be important drugs for the treatment of COVID-19. In this article, the research and application of chloroquine and hydroxychloroquine are reviewed from the aspects of pharmacokinetics, drug interaction, clinical research progress, treatment plan optimization and resolution of optical enantiomers. The possible problems are summarized in order to provide reference for further research and clinical application of quinoline alkaloids in the treatment of COVID-19.

Evaluation of ß-agonists in blood meal: Validation of determination method and potential pathway for reentry into the environment.

ß-agonists, which have been illegally used in animal production in some countries, can induce bioaccumulation when blood is converted by rendering into blood meal. Unfortunately, available data on this topic are scarce, which result in lack of risk assessment. Therefore, in this research, a method for simultaneous determination of 22 ß-agonists in blood meal by liquid chromatography coupled with tandem mass spectrometry using isotope dilution was developed. The recoveries of the developed method ranged from 68.6% to 118.8% with RSD at below 20%. the limit of detection (LOD) is blew 1 µg/kg. The change in agonist form added and incurred blood into blood meal and long stability of ß-agonist in blood meal were studied. Then, we analyzed blood meal for 22 agonists using this method. The results suggest blood meal is a possible pathway for agonist reentry into animals. Potential risks of agonist residues in blood meal were examined. This study is the first to explore source of ß-agonist residues in blood meal, change in processing produce and stability in stored stage.

Simultaneous determination of antibiotics and amantadines in animal-derived feedstuffs by ultraperformance liquid chromatographic-tandem mass spectrometry.

In this study, a method for simultaneous determination of 40 antibiotics from 6 different drug families (7 quinolones, 5 penicillins, 8 macrolides, 2 lincosamides, 4 tetracyclines, and 13 sulfonamides) and 3 amantadines in animal-derived feedstuffs (ADF) through ultraperformance liquid chromatography-tandem mass spectrometry using a new lipid-removing solid-phase extraction column PRiME HLB was developed. The sample was extracted with 20 mL extraction solution and then purified and concentrated with PRiME HLB. The eluent was evaporated to dryness under nitrogen and analyzed with LC-MS/MS using acetonitrile and 0.1% formic acid as the mobile phase via gradient elution. Under the optimum conditions, recoveries were 65.8% to 104.4% with a relative standard deviation of <15% at spiked levels of 5.0 µg/kg to 100 µg/kg. The limits of detection ranged from 0.5 µg/kg to 5 µg/kg. 15 of the 43 drugs were found in ADF. Sulfonamides, fluoroquinolones, macrolides, tetracyclines, and amantadines were detected, with the highest levels reaching 325 µg/kg.

Accumulation and Determination of Phenylethanolamine A Residue in Hair of Swine and Sheep.

The present study proposed the use of liquid chromatography-tandem mass spectrometry to detect the novel ß-agonist phenylethanolamine A (PEA) in incurred hair samples of swine and sheep and to assess its accumulation for residue monitoring. The method showed good percent recoveries ranging from 93.2% to 102% and good coefficient of variation at <15%. The experiment was conducted in swine (24 treated and 4 controls) and sheep (3 treated and 1 control). PEA concentration was determined in hair during the treatment. High residue concentrations were present in hair as early as Day 24 (14.8 ± 3.6 and 25.8 ± 7.6 ng/g) and Day 21 (23.4 ± 6.6 ng/g) for swine and sheep; these residues persisted until withdrawal on Days 14 and 21. Results showed high PEA accumulation in hair, thereby indicating the use of hair as a matrix in the control of PEA abuse in farm animals.

Simultaneous Detection of 21 Kinds of Mycotoxins and Their Metabolites in Animal Plasma with Impurity Adsorption Purification Followed by Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A novel method for simultaneous detection of mycotoxins (e.g.,aflatoxin B1) or their metabolic residues in animal plasma with impurity adsorption purification followed ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed.Extraction of mycotoxins and their metabolites from animal plasma sample was performed with 0.1％ formic acid-acetonitrile solution after addition of sodium chloride and hydrous magnesium sulfate.The extract was then dehydrated and purified with hydrous magnesium sulfate,C18,primary secondary amine,and alumina-A.3 mL of the supernatant was evaporated and re-dissolved with 0.5 mL of 0.1％ formic acid aqueous solution/acetonitrile (70∶ 30,V/V) for UPLC-MS/MS detection.The analytes were separated by a C18 column utilizing gradient elution with 0.1％ formic acid aqueous solution containing 0.5 mmol of ammonium acetate and 0.1％ formic acid-methanol solution,and finally detected by tandem mass spectrometry in positive/negative ESI mode.Identification and quantification were achieved by LC-MS/MS with multi-reaction monitoring (MRM).Good linearity in response was obtained in the analytes concentration range of 0.05-100 ng/mL with correlation coefficients larger than 0.99.The limits of quantification (S/N=10) were around 0.05-0.5 ng/mL.The recoveries of mycotoxins and their metabolites spiked in blank plasma samples were in the range of 62.0％-116.4％,with relative standard deviations (RSDs) less than 19.0％.

Validation of a confirmatory method of salbutamol in sheep hair by UPLC-MS/MS and its application to pharmacokinetic study.

A new method for determining salbutamol in hair of sheep by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was established. Samples were extracted with 0.1M of HCl solution. The mixture was heated to 60 °C in a water bath and kept at this temperature for 4h. The extracts were purified through SPE method and then dried with nitrogen. Residues were redissolved in mobile phase. The target compound was determined by UPLC-MS/MS with BEH-C18 column. The usefulness and feasibility of different treatment procedures of hair containing salbutamol were evaluated. The range of linearity was 1-100 ng/g. The LOD was 0.3 ng/g, and the LOQ was 1 ng/g. Recoveries were 89-106%, and coefficients of variation were 3.2-13.9%. Pharmacokinetics of salbutamol was studied in healthy sheep after oral administration of 150 µg/kg body weight salbutamol for 21 consecutive days. Salbutamol residues in hair were still detected after 21 days of administration.

Determination of 26 Mycotoxins in Feedstuffs by Multifunctional Cleanup Column and Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A rapid high-throughput method for the determination of 26 mycotoxins involving multifunctional cleanup column coupled with liquid chromatography-tandem mass spectrometry ( LC-MS/MS) was developed and validated for the determination in feedstuffs. The feedstuff samples were extracted by ultrasonic treatment for 1 hour and the extraction solvent was acetonitrile/water/formic acid (84:15. 9:0. 1, V/V). 1 mL of the supernatant layer was purified by a commercial Mycospin 400 multifunctional cleanup column, then dried and re-dissolved by 0. 25 mL water/methanol/formic acid (95:4. 9:0. 1, V/V) in a vial for injection into the LC-MS/MS system. Chromatographic analyses were carried out on a reversed phase C18 column and using a gradient elution with 0. 1% formic acid aqueous solution and 0. 1% formic acid methanol solution. The mass spectrometer was operated in a multiple reaction monitoring ( MRM) mode that selected one precursor ion and two product ions for each target compound. Validation studies were carried out in maize and soybean meal as representative matrixes. The most target compounds had different level of matrix effects. So, matrix-matched calibration was adopted for quantification. Mean recoveries from spiked samples at three levels ranged from 61 . 9% to 119 . 5% with relative standard deviations of 0 . 8%-18 . 6%. Limits of quantification ranged from 0. 5 μg/kg to 25 μg/kg.

Study on Influences of Enzymolysis and Organic Solvent Extraction on Determination of 2 Kinds of β2-Agonist Residues in Sheep Plasma and Urine / 分析化学

Two kinds of β2-agonistresidues in sheep plasma and urine were disposed by enzymolysis and organic solvent extraction pretreatment methods, and UPLC-MS/MS was used for the qualitative and quantitative analysis. Detection results were compared to study the influences of two pretreatment methods. The experimental results showed that more than 95% of Ractopamine and 40% of Salbutamol exist in the conjugated form in sheep plasma. The detection results of 2 kinds of β2-agonist residues were significantly enhanced when adding β-glucuronidase/aryl sulfatase. The experimental repeatability is very poor ( RSD>40%) when the enzymolysis was not carried out. There were 57% of Ractopamine and less than 1% of Salbutamol exists in the conjugated form in sheep urine. Enzymolysis pretreatment method was useful for the Ractopamine residues determination in urine, and Enzymolysis pretreatment method was useless for Salbutamol determination in urine. Matrix effect of plasma was less than the effects of urine. The influence of organic solvent extraction pretreatment method on the detection results was unremarkable, and there was the possibility that organic solvent extraction could lead partial loss of target compound in extraction process. However, it did not influence the detection results by using internal standard calibration.

Expression of E-cadhrein and its relationship with differentiation and metastasis in gastric cancer / 肿瘤研究与临床

Objective To investigate the expression of E-cadherin(E-cad)and the relationship with the Lauren classification,the degree of histological differentiation,the clinical stage,the depth of invasion,lymph node metastasis and distant metastasis of gastric cancer. Methods 80 cases architecture of gastric cancer and normal tissue were collected.The expression level of E-cad in 80 cases of gastric carcinomas and their metastatic lymph node tissues were examined by immunohistochemical assays.Results The expression rate of E-cad in 80 cases of gastric carcinomas Was 55.00%.The expression level of E-cad was positively correlated with the Lauren classification,the degree of histological differentiation,the clinical stage,the depth of invasion,lymph node metastasis and distant metastasis(P＜0.05),but Was not correlated to patients sex,age and tumor size.The expression rates of E-cad in metastatic gastric carcinoma of primary lesions and lymph nodes metastasis were 35.48%and 32.26%. respectively. Furthermore, E-cad expression in metastatic gastric carcinoma was significandy correlated with primary lesions and lymph node memstasis(r=0.4978,P＜0.05).Conclusion The expression level of E-cad in gastric carcinoma Was closely correlated with the degree of tumor differentiation,infiltration and transferring.