Qualitative and Quantitative Determination of Decoquinate in Chicken Tissues by Gas Chromatography Tandem Mass Spectrometry.

A novel precolumn derivatization-GC-MS/MS method was developed for the determination of decoquinate residues in chicken tissues (muscle, liver, and kidney). The samples were extracted and purified by liquid-liquid extraction combined with solid-phase extraction and derivatized with acetic anhydride and pyridine. The recovery rates for decoquinate were 77.38~89.65%, and the intra-day and inter-day RSDs were 1.63~5.74% and 2.27~8.06%, respectively. The technique parameters meet the necessities for veterinary drug residue detection in China, the US, and the EU. Finally, the method was applied to analyze tissues of 60 chickens bought from a neighborhood supermarket, and solely one sample of chicken muscle contained 15.6 µg/kg decoquinate residue.

Combining GC-MS/MS with a LLE-SPE sample pretreatment step to simultaneously analyse enrofloxacin and ofloxacin residues in chicken tissues and pork.

A widely applicable original gas chromatography-tandem mass spectrometry (GC-MS/MS) method was explored to qualitatively and quantitatively measure enrofloxacin and ofloxacin residues in chicken tissues and pork. The experimental samples were processed based on liquid-liquid extraction (LLE) and solid-phase extraction (SPE). Trimethylsilyl diazomethane (TMSD) was chosen to react derivatively with enrofloxacin and ofloxacin. In total, 78.25% âˆ¼ 90.56% enrofloxacin and 78.43% âˆ¼ 91.86% ofloxacin was recovered from the blank fortified samples. The limits of detection (LODs) were 0.7-1.0 µg/kg and 0.1-0.2 µg/kg, respectively. The limits of quantitation (LOQs) were 1.6-1.9 µg/kg and 0.3-0.4 µg/kg, respectively. It was verified that various experimental data met the requirements of the FAO & WHO (2014) for the detection of veterinary drug residues. Real samples obtained from local markets were analysed using the established method, and no residues of enrofloxacin or ofloxacin were detected in the samples.

Untargeted and targeted metabolomics identify metabolite biomarkers for Salmonella enteritidis in chicken meat.

Salmonella Enteritidis easily contaminate chicken during slaughtering, processing, transportation, and sales, which seriously endangers human health. This study aimed to identify metabolite biomarkers for Salmonella Enteritidis contamination in chicken meat. UPLC-Q-Orbitrap MS untargeted metabolomics analysis identified 441 and 240 confidently metabolites in positive and negative ion mode, respectively. Thirty metabolites were defined as potential biomarkers for Salmonella enteritidis contamination in chicken meat. UPLC-QQQ-MS based targeted metabolomics was used to quantitatively analyze candidate metabolite biomarkers in Salmonella enteritidis contaminated and fresh chicken samples. A total of 10 candidate metabolite biomarkers were confirmed in the validation set, among which acetylcholine, l-Methionine, l-Proline, l-Valine, and l-Norleucine were identified as biomarkers for Salmonella Enteritidis contamination in chicken. The combined receiver operating characteristic curve analysis of the five biomarkers achieved an AUC of 0.956, indicating their high sensitivity and specificity in predicting Salmonella Enteritidis in raw chicken. In conclusion, the present study identified five metabolite biomarkers for Salmonella enteritidis in raw chicken. These results provide a potential theoretical basis for developing Salmonella Enteritidis detection methods in raw chicken.

Simultaneous quantitative determination of residues of abamectin, ivermectin, albendazole and its three metabolites in beef and chicken by HPLC-PDA.

Antimicrobial drugs are frequently used in a combination or shuttle way to cope with coinfection of bacteria or parasites and prevent drug resistance, thus the accurate quantification of multiple drug residues in animal-derived foods is crucial to ensure food safety. Here, a simple and efficient high-performance liquid chromatography-photodiode array (HPLC-PDA) method was established for the simultaneous quantitative screening of six common residues of antiparasitic drugs, including abamectin (ABM), ivermectin (IVM), albendazole (ABZ) and the three metabolites of ABZ in beef and chicken. The LODs and LOQs for six target compounds in beef and chicken are determined to be 3.2 to 12.5 µg/kg and 9.0 to 30.0 µg/kg, respectively. The calibration curves show good linearity (R2 ≥ 0.9990) between the peak area and concentration. The recoveries from the fortified blank samples are all above 85.10%. Finally, the applicability of the HPLC-PDA method is successfully demonstrated by the real sample analysis.

Qualitative and quantitative determination of tilmicosin in poultry eggs by gas chromatography tandem mass spectrometry after derivatization with acetic anhydride.

A novel GC-MS/MS analytical method was established for the qualitative and quantitative determination of tilmicosin in poultry (Jinghai yellow chicken, Gaoyou duck and Yangzhou goose) eggs. The method was based on LLE and SPE for sample extraction and purification. Pyridine and acetic anhydride were used for the derivatization reaction. When tilmicosin was added to blank poultry egg samples at the LOQ and 75 µg/kg, 150 µg/kg, and 300 µg/kg, the recoveries ranged from 72.80% to 88.75%, the intraday and interday RSDs ranged from 2.31% to 4.56% and 3.29%-5.61%, respectively, and the LODs and LOQs ranged from 3.8 to 5.6 µg/kg and 8.4-10.5 µg/kg, respectively. These results confirmed that the parameters of this novel method meet the requirements of the FAO & WHO (2014) for veterinary drug residue testing. Poultry egg samples purchased from the local market were analysed according to the established method and only one egg sample was found to contain 18.9 µg/kg of tilmicosin.

Determination of Levamisole and Mebendazole and Its Two Metabolite Residues in Three Poultry Species by HPLC-MS/MS.

A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to simultaneously analyze levamisole (LMS) and mebendazole (MBZ) and its two metabolites, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry muscle (chicken, duck and goose). In the sample preparation process, basic ethyl acetate was used as the extraction agent, and the extracted samples were back-extracted with hydrochloric acid, purified by Oasis MCX solid-phase extraction (SPE) cartridges, and reconstituted in the initial mobile phase after being blown dry with nitrogen. Chromatographic separation was performed on an Xbridge C18 column (4.6 mm × 150 mm, 5 µm) with 0.1% formic acid in water and acetonitrile as the mobile phases, and gradient elution was performed at a flow rate of 0.6 mL/min and a column temperature of 35 °C. In blank poultry muscle samples, the spiked concentrations of LMS, MBZ, HMBZ, and AMBZ were within the range of the limit of quantitation (LOQ) to 25 µg/kg. The peak areas of the four target drugs had a good linear relationship with the concentration, and the determination coefficient (R2) values were higher than 0.9990. The average recoveries of LMS, MBZ, HMBZ, and AMBZ were 86.77-96.94%; the intraday relative standard deviations (RSDs) were 1.75-4.99% at LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL, and 2.0 MRL; the interday RSDs were 2.54-5.52%; and the LODs and LOQs were 0.04-0.30 µg/kg and 0.12-0.80 µg/kg, respectively.

Interdependence and organizational citizenship behavior: exploring the mediating effect of group cohesion in multilevel analysis.

The authors investigated the mechanism of group cohesion in the relationship between (a) task interdependence and goal interdependence and (b) individuals' organizational citizenship behavior (OCB). The authors adopted a multilevel perspective to facilitate understanding of the complex relations among variables. They collected data from 53 supervisors and 270 employees from R&D departments in Taiwan. The authors found that group cohesion fully mediated the effects of task interdependence and goal interdependence on employees' OCB. In addition, task interdependence had a greater effect on group cohesion than did goal interdependence. The authors discuss implications and suggestions for future research.

Prescription-filling process reengineering of an outpatient pharmacy.

Shortening waiting times is the most obvious and effective method of increasing service quality. As the workforce is limited, it is necessary to reform current systems of medical care and improve the efficiency of medical care. After process reengineering was proposed in 1990s, however, this concept has not yet been commonly applied to medical centers. The subject of this study was an outpatient pharmacy in a medical center. This study applied the methods of a time study to measure field observations and as an analytic tool in process reengineering. The results show that the pharmacists were hindered in filling prescriptions for the following reasons: the preparation of certain prescription units, the menial sorting of medicines and also storage issues related to medicines. Improving the process will decrease time wasted by 10.41% and enhance service by 8.95%. The reengineering process resulted not only in a reduction in outpatients' waiting time but also enhanced the quality and competitiveness of the Hospital's medical treatment.