Antibiotics are widely used in veterinary medicine mainly for treatment and prevention of diseases. The aminoglycosides are one of the antibiotics classes that have been extensively employed in animal husbandry for the treatment of bacterial infections, but also as growth promotion. The European Union has issued strict Maximum Residue Levels (MRLs) for aminoglycosides in several animal origin products including bovine milk, bovine, swine and poultry muscle. This paper describes a fast and simple analytical method for the determination of ten aminoglycosides (spectinomycin, tobramycin, gentamicin, kanamycin, hygromycin, apramycin, streptomycin, dihydrostreptomycin, amikacin and neomycin) in bovine milk and bovine, swine and poultry muscle. For sample preparation, an extraction method was developed using trichloroacetic acid and clean up with low temperature precipitation and C18 bulk. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to carry out quantitative analysis and liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOF-MS) was used to screening purposes. Both methods were validated according to the European Union Commission Directive 2002/657/EC. Good performance characteristics were obtained for recovery, precision, calibration curve, specificity, decision limits (CCα) and detection capabilities (CCβ) in all matrices evaluated. The detection limit (LOD) and quantification limit (LOQ) were ranging from 5 to 100ngg(-1) and 12.5 to 250ngg(-1), respectively. Good linearity (r)-above 0.99-was achieved in concentrations ranging from 0.0 to 2.0×MRL. Recoveries ranged from 36.8% to 98.0% and the coefficient of variation from 0.9 to 20.2%, noting that all curves have been made into their own matrices in order to minimize the matrix effects. The CCβ values obtained in qualitative method were between 25 and 250ngg(-1). The proposed method showed to be simple, easy, and adequate for high-throughput analysis of a large number of samples per day at low cost.

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This study presents the development and validation of a simple method for the detection and quantification of six β-lactam antibiotics residues (ceftiofur, penicillin G, penicillin V, oxacillin, cloxacillin and dicloxacillin) in bovine milk using a fast liquid-liquid extraction (LLE) for sample preparation, followed by liquid chromatography-electrospray-tandem mass spectrometry (LC-MS/MS). LLE consisted of the addition of acetonitrile to the sample, followed by addition of sodium chloride, centrifugation and direct injection of an aliquot into the LC-MS/MS system. Separation was performed in a C(18) column, using acetonitrile and water, both with 0.1% of formic acid, as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Limits of detection ranged from 0.4 (penicillin G and penicillin V) to 10.0 ng ml(-1) (ceftiofur), and linearity was achieved. The decision limit (CCα), detection capability (CCβ), accuracy, inter- and intra-day repeatability of the method are reported.

The methods of analysis of sulfonamides (SFAs) using CE are reviewed. Sulfonamides were the first antimicrobial group of drugs used in medical treatment. These compounds are still used today in medicine and widely are employed in veterinary medicine, also for their growth promoter effects. Improved methods of analysis of sulfonamides are a constant challenge for researchers. CE is a new trend in the fields of pharmaceutical and food analyses. Several methods for the determination of SFAs by CE have been published in recent years, and the present review considers applications in quality control of pharmaceutical dosage forms, food analysis, determinations in serum, and other biological fluids as well as in electrophoresis experiments which examine the behavior of this class of compounds for theoretical studies of the technique. This review covers studies ranging from the pioneering works on sulfonamide analyses using classical electrophoresis to the more recent CE methods coupled to tandem mass spectrometers. The sections are divided following the EC modes like CZE, MEKC, and hyphenated methods (CE-MS, CE-MS/MS). A brief compilation of theoretical findings of sulfonamides electrophoretic behavior is also included. Parameters such as recoveries, LOD and LOQ, among others, are examined, covering works published until August 2008. This review can contribute to further research aimed to improve the analysis of SFAs by CE.