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Bohm D.A.,National Reference Laboratories for Contaminants and Residues | Stachel C.S.,National Reference Laboratories for Contaminants and Residues | Gowik P.,National Reference Laboratories for Contaminants and Residues
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2013

A simple, rapid, and sensitive method for the determination and confirmation of the aminoglycosides streptomycin, dihydrostreptomycin, spectinomycin, apramycin, kanamycin, paromomycin, gentamicin and neomycin in cow's milk as well as in bovine and porcine muscle and kidney was developed. Validation was performed on the basis of an in-house concept with different factor-level combinations in accordance with Commission Decision 2002/657/EC. After extraction with trichloroacetic acid solution, clean-up was performed by way of SPE. LC-MS/MS analysis was carried out by means of an HILIC column for the separation of the analytes, and by using MS/MS in positive ESI mode to measure the transitions of the substances in MRM mode. For quantification, matrix calibration curves in the linear range around the MRLs as well as the internal standard tobramycin were used. The calculated validation parameters like CCα, CCβ, recovery (94-103%), relative repeatability RSDr (3.6-9.7%), and relative within-laboratory reproducibility RSDwR (4.6-10.0%) fulfilled the requirements of Commission Decision 2002/657/EC. © 2013 Copyright BVL. Source


Bohm D.A.,National Reference Laboratories for Contaminants and Residues | Stachel C.S.,National Reference Laboratories for Contaminants and Residues | Gowik P.,National Reference Laboratories for Contaminants and Residues
Analytical and Bioanalytical Chemistry | Year: 2012

The presented multi-method was developed for the confirmation of 37 antibiotic substances from the six antibiotic groups: macrolides, lincosamides, quinolones, tetracyclines, pleuromutilines and diamino-pyrimidine derivatives. All substances were analysed simultaneously in a single analytical run with the same procedure, including an extraction with buffer, a clean-up by solid-phase extraction, and the measurement by liquid chromatography tandem mass spectrometry in ESI+ mode. The method was validated on the basis of an in-house validation concept with factorial design by combination of seven factors to check the robustness in a concentration range of 5-50 μg kg1. The honeys used were of different types with regard to colour and origin. The values calculated for the validation parameters-decision limit CCaα (range, 7.5-12.9 μg kg1), detection capability CC (range, 9.4-19.9 μg kg1), within-laboratory reproducibility RSDwR (<20% except for tulathromycin with 23.5% and tylvalosin with 21.4 %), repeatability RSDr (<20% except for tylvalosin with 21.1%), and recovery (range, 92-106%)- were acceptable and in agreement with the criteria of Commission Decision 2002/657/EC. The validation results showed that themethod was applicable for the residue analysis of antibiotics in honey to substances with and without recommended concentrations, although some changes had been tested during validation to determine the robustness of the method. © 2012 Springer-Verlag. Source


Bohm D.A.,National Reference Laboratories for Contaminants and Residues | Stachel C.S.,National Reference Laboratories for Contaminants and Residues | Gowik P.,National Reference Laboratories for Contaminants and Residues
Analytica Chimica Acta | Year: 2010

The method was specifically developed for the determination and confirmation of streptomycin in apple samples using the whole mellow apple. The method is simple, rapid, sensitive and was validated for streptomycin in accordance with SANCO/3131/2007. After extraction with phosphate buffer and a pH change, the clean-up was performed by the way of SPE with polymeric phase. The LC-MS/MS analysis was carried out using a HILIC column for the separation of the analytes and a triple quadrupole mass spectrometer in positive ESI mode to measure the transitions of the substances in MRM mode. For the quantification of streptomycin a matrix calibration curve in the linear range of 1.0-20μgkg-1 and the internal standard dihydrostreptomycin (10μgkg-1) were used. The calculated validation parameters like the recovery (101-105%) for 2, 5, 10 and 20μgkg-1 and the relative standard deviation (RSD, 4.1-11.4%) of the 6 replicates fulfil the requirements of SANCO/3131/2007. The LOQ was determined as 2μgkg-1. © 2010 Elsevier B.V. Source


Bohm D.A.,National Reference Laboratories for Contaminants and Residues | Stachel C.S.,National Reference Laboratories for Contaminants and Residues | Gowik P.,National Reference Laboratories for Contaminants and Residues
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

A method was specifically developed for the determination and confirmation of streptomycin and dihydrostreptomycin in different types of honey. The method is simple, rapid, sensitive and was validated for streptomycin and dihydrostreptomycin in accordance with Commission Decision 2002/657/EC. After extraction with phosphate buffer and a pH change, clean-up was performed via SPE with polymeric phase. LC-MS/MS analysis was carried out using two different HILIC columns for the separation of the analytes and using a triple quadrupole mass spectrometer in positive ESI mode to measure the transitions of the substances in MRM mode. For the quantification of both substances, matrix calibration curves in a linear range of 5-80 g kg -1 were used. The validation parameters established for streptomycin and dihydrostreptomycin, CCα (11.8 and 11.5 μgkg -1, respectively), CCβ (18.9 and 19.9 μgkg -1, respectively), recovery (97 and 101%, respectively) and the relative within-laboratory reproducibility RSD wR (16.4 and 20.8%, respectively) at the recommended concentration of 40 μgkg -1, fulfil the requirements of Commission Decision 2002/657/EC. © 2012 Taylor & Francis. Source


Bohm D.A.,National Reference Laboratories for Contaminants and Residues | Stachel C.S.,National Reference Laboratories for Contaminants and Residues | Gowik P.,National Reference Laboratories for Contaminants and Residues
Journal of AOAC International | Year: 2011

The described multimethod is suited for the determination of 53 substances of eight antibiotic groups-tetracyclines, quinolones, macrolides, sulfonamides, diphenylsulfones, diamino-pyrimidine derivatives, pleuromutilines, and lincosamides-in cattle and pig muscle. All substances were analyzed simultaneously with the same sample preparation and in one HPLC/MS/MS run. The validation of the multimethod was successfully accomplished with the help of an alternative in-house validation concept requiring only 48 experiments. The substances were validated at concentrations of 0.25, 0.5, 1.0, 1.5, and 2.0 × MRL (maximum residue limit) or 5, 10, 20, 30, and 40 μg/kg for substances without an MRL. The calculated relevant validation parameters were based on and comply with the requirements of Commission Decision 2002/657/EC, i.e., the decision limit, detection capability, repeatability, within-laboratory reproducibility, and recovery. The robustness of the method was demonstrated by varying seven factors of the analytical procedure. Several proficiency tests were carried out successfully to provide evidence for the applicability of the method. Source

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