A Liquid Chromatography - Tandem Mass Spectrometry Approach for the Identification of Mebendazole Residue in Pork, Chicken, and Horse.

A confirmatory and quantitative method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of mebendazole and its hydrolyzed and reduced metabolites in pork, chicken, and horse muscles was developed and validated in this study. Anthelmintic compounds were extracted with ethyl acetate after sample mixture was made alkaline followed by liquid chromatographic separation using a reversed phase C18 column. Gradient elution was performed with a mobile phase consisting of water containing 10 mM ammonium formate and methanol. This confirmatory method was validated according to EU requirements. Evaluated validation parameters included specificity, accuracy, precision (repeatability and within-laboratory reproducibility), analytical limits (decision limit and detection limit), and applicability. Most parameters were proved to be conforming to the EU requirements. The decision limit (CCα) and detection capability (CCß) for all analytes ranged from 15.84 to 17.96 µgkg-1. The limit of detection (LOD) and the limit of quantification (LOQ) for all analytes were 0.07 µgkg-1 and 0.2 µgkg-1, respectively. The developed method was successfully applied to monitoring samples collected from the markets in major cities and proven great potential to be used as a regulatory tool to determine mebendazole residues in animal based foods.

Multiresidue Screening of Veterinary Drugs in Meat, Milk, Egg, and Fish Using Liquid Chromatography Coupled with Ion Trap Time-of-Flight Mass Spectrometry.

New approaches to veterinary drug screening based on liquid chromatography-mass spectrometry (LC-MS/MS) and time-of-flight mass spectrometry (ToF/MS) are rapid and have high selectivity and sensitivity. In this study, we developed a multiresidue method for screening over 100 veterinary drug residues using ion trap (IT)-ToF/MS. The screened compounds comprised major drug classes used in veterinary practice, representing the following: amphenicols, anthelmintics, benzimidazoles, ß-lactams, coccidiostats, ionophores, macrolides, non-steroidal anti-inflammatory drugs, quinolones, sulfonamides, tetracyclines, and tranquilizers. The method was developed based on chromatographic retention time, specific accurate mass, isotope distribution, and fragment data. Each compound was validated at three levels, and the mass accuracy, accuracy, and repeatability were calculated. All parameters showed acceptable values and conformed to the Commission Decision 2002/657/EC criteria. This screening method can simultaneously analyze over 100 veterinary drugs in meat, milk, eggs, and fish in a single analytical run.

Veterinary drug residues in domestic and imported foods of animal origin in the Republic of Korea.

The Korean National Residue Programme comprises three different approaches for evaluating domestic and imported foods of animal origin: monitoring, surveillance/enforcement and an exploratory test programme. Monitoring and surveillance/enforcement testing programmes are routinely implemented by 17 Provincial Veterinary Services for domestic products and regional offices of the Animal and Plant Quarantine Agency (QIA) for imported products. The exploratory project conducted at QIA headquarters is designed to test substances that are not included in monitoring and enforcement testing programmes. Here, we carried out exploratory testing for determining the presence of 42 veterinary drugs that have no established Korean maximum residue limits and analysed their levels simultaneously, in a total of 3108 samples of domestic and imported animal-origin foods. Of the tested drugs, acetylsalicylic, paracetamol, clopidol, diclazuril, amprolium, toltrazuril and its metabolites (toltrazuril sulphone and toltrazuril sulphoxide) and phenylbutazone and its metabolites (oxyphenylbutazone) were detected.

Chemical residues and contaminants in foods of animal origin in Korea during the past decade.

Residues of veterinary drugs, pesticides, and environmental contaminants in domestic and imported foods of animal origin were monitored by the National Residue Program and inspection service in Korea in the past decade. In all, 134 substances were analyzed in the monitoring plan; 35 substances were examined in the surveillance and enforcement testing program, and 27 substances were investigated in exploratory projects. The overall trend of violation rates gradually decreased over the past decade. Pesticides were not found in any domestic samples of animal origin. The violation rates of chlortetracycline and oxytetracycline decreased, but quinolone and penicillin detections increased in Korea. Several kinds of residue violations of veterinary drugs, endosulfan, or dioxins were found in the imported products each year. In an example event in 2008, the Korea monitoring plan contributed globally to investigate the dioxin contamination from Chilean pork. Continuous monitoring based on internationally harmonized standards and methods provides the essential scientific basis to manage and ensure food safety.