Development of an analytical method for multi-residue quantification of 18 anthelmintics in various animal-based food products using liquid chromatography-tandem mass spectrometry / 药物分析学报

In this study,we developed a simple screening procedure for the determination of 18 anthelmintics(including benzimidazoles,macrocyclic lactones,salicylanilides,substituted phenols,tetrahydropyr-imidines,and imidazothiazoles)in five animal-derived food matrices(chicken muscle,pork,beef,milk,and egg)using liquid chromatography-tandem mass spectrometry.Analytes were extracted using acetonitrile/1％acetic acid(milk and egg)and acetonitrile/1％acetic acid with 0.5 mL of distilled water(chicken muscle,pork,and beef),and purified using saturated n-hexane/acetonitrile.A reversed-phase analytical column and a mobile phase consisting of(A)10 mM ammonium formate in distilled water and(B)methanol were used to achieve optimal chromatographic separation.Matrix-matched standard calibration curves(R2≥0.9752)were obtained for concentration equivalent to ×1/2,×1,×2,×3,×4,and ×5 fold the maximum residue limit(MRL)stipulated by the Korean Ministry of Food and Drug Safety.Recoveries of 61.2-118.4％,with relative standard deviations(RSDs)of ≤19.9％(intraday and interday),were obtained for each sample at three spiking concentrations(×1/2,×1,and ×2 the MRL values).Limits of detection,limits of quantification,and matrix effects were 0.02-5.5 μg/kg,0.06-10 μg/kg,and-98.8 to 13.9％(at 20 μg/kg),respectively.In five samples of each food matrix(chicken muscle,pork,beef,milk,and egg)purchased from large retailers in Seoul that were tested,none of the target analytes were detected.It has therefore been shown that this protocol is adaptable,accurate,and precise for the quantification of anthelmintic residues in foods of animal origin.

Residue Analysis of Oxytetracycline in Milk Sample by Two Different Chromatographic Methods and Determination of Ionization Constant Values

In thepresent study, two analytical methods for the residue analysis of oxytetracycline in milk sample have been generated. InHPLC method, the analysis was performed on an X Terra RP-18 column at 25 °C with the mobile phase as methanol: water (20 : 80 )(v/v) modified to pH 5. For the second method capillary electrophoresis system was used. The analysis of oxytetracycline in milk sample could be achieved without using organic modifier in a 58 cm length capillary at a working voltage of 12 kV with 20 mM NaH2PO4-H3PO4(pH 7) by capillary electrophoresis. Tetracycline was used as internal standard in both methods. The results calculatedfrom both methods were compared to each other. The calculated data for drugs was checked with the data predicted by the SPARC on-line pKa estimator

Method Establishment and Samples Screening for the Determination of Forbidden Pesticide Residues in Panax ginseng C.A.Mey / 中国药学杂志

OBJECTIVE： To establish a method for the determination of 33 kinds of pesticide residues in Panax ginseng C.A.Mey by GC-MS/MS and LC-MS/MS. METHODS： The 53 chemical monomers of 33 pesticide residues clearly prohibited by the Chinese ministry of agriculture were selected as the detection indicators. The samples were extracted with acetonitrile by high speed homogenizer. An LC-MS/MS analysis was performed on a CORTECSTM UPLC C18(2.1 mm×150 mm, 1.6 μm) column with isocratic elution of 0.1% formic acid (containing 5 mmol•L-1 ammonium formate) is mobile phase A, 95% acetonitrile(containing 5 mmol•L-1 ammonium formate and 0.1% formic acid)is mobile phase B.Electrospray ionization(ESI)source was applied by positive ionization in multiple reaction monitoring(MRM)modes. GC-MS/MS analysis was performed on a DM17ms(30 m×0.25 mm, 0.25 μm)capillary column with electron impact(EI)source, electron impact (EI) source was applied by positive ionization in multiple reaction monitoring modes (MRM). RESULTS: The correlation coefficient r of 33 pesticide residues showed good linearity in the linear range of 2 to 20 ng•mL-1 was greater than 0.990 0. The average recoveries at spiked levels of low level and high level (0.01 and 0.04 mg•kg-1), repeat 5 times per level. The average recovery was 87.57%-120.98%, and the RSD was between 1.45%-14.03%. CONCLUSION： The method can quickly and effectively detect pesticide residues in ginseng.

Pesticides Contamination and Analytical Methods of Determination in Environmental Matrices in Malaysia and Their Potential Human Health Effects – A Review

@#Pesticides application is essential in protecting crops and increases their productivity. However, this causes the pesticide residues to contaminate the crops and their surrounding environment that will eventually lead to exposure to human being. There is very little understanding on the human health effects of pesticides, thus many studies are being carried out for this purpose. In conjunction to this, there are various analytical methods on multi-residue pesticides analysis that have been developed over the years in various samples. This review provides an overview of the reported concentration of pesticides, the extraction and determination techniques of pesticides in environmental samples and the potential health effects they imposed on human in Malaysia from 2007 to 2017.

Residue Determination of cis-Epoxiconazole Enantiomers in Fruit and Tea by Ultra Performance Convergence Chromatography Combined with Quadrupole Time-of-Flight Mass Spectrometry / 分析化学

Abstract A chiral separation and residue determination method for cis-epoxiconazole enantiomers in apple, grape and tea samples was developed and validated by ultra performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry ( UPC2-QTOF/MS) . The Chrial CCA column was used to separate cis-epoxiconazole enantiomers and the chromatography conditions ( mobile phase modifier and proportion, column temperature, automated backpressure regulator, and auxiliary solvent ) were optimized. Samples were extracted by acetonitrile, and respectively purified by Cleanert TPT or Pesti-Carb solid phase extraction ( SPE ) columns, then analyzed by UPC2-QTOF/MS. The optimum conditions were as follows:mobile phase was CO2/isopropanol (95: 5, V/V), flow-rate was 2. 0 mL/min, automated backpressure regulator (ABPR) was 13. 79 MPa, column temperature was 30℃, with a post-column mauxiliary solvent of methanol/water (1:1, V/V) containing 2 mmol/L ammonium formate. The analyte was quantified by matrix external standard method. The results showed that linear range of this method was 0. 01-1. 00 mg/L, and the correlation coefficients were above 0 . 99 . The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 005, 0. 025 and 0. 25 mg/kg) in fruit matrix were 67. 9%-92. 8% with relative standard deviations (RSDs, n=6) less than 10%, and the limit of quantification (LOQ) of enantiomers was 0. 005 mg/kg. The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 01, 0. 05 and 0. 5 mg/kg) in black tea were 74 . 1% -84 . 0% with RSDs ( n=6 ) less than 8%, and the LOQ for these two enantiomers was 0. 01 mg/kg. This method is rapid, convenient and reliable, and could meet the requirement of residue analysis.

Residue Analysis on Heavy Metals in Medicinal Leeches / 世界科学技术-中医药现代化

This study was aimed to detect the heavy metal residues of medicinal leeches, in order to understand the current market circulation situation of medicinal leeches, and to analyze possible factors which may cause heavy metal pollution, and to provide references for the standardized safe cultivation of medicinal leeches. Inductively coupled plasma mass spectrometry (ICP-MS) technique was applied to detect heavy metal residues in medicinal leeches. The results showed that medicinal leech samples tested for heavy metal content severely exceeded the standard, which caused a great threat to the safety of medication. It was conclude that more attentions should be paid on factors for causing heavy metal accumulation within medicinal leeches during the breeding process. The related department should also list safety limits explicitly and separately for animal drugs such as medicinal leech during the development of quality standards of Chinese materia medica.