Desenvolvimento de método analítico para quantificação de lactonas macrocíclicas em músculo bovino por cromatografia líquida de alta eficiência acoplada à espectrometria de massas (LC-MS/MS)

Abstract

The control of chemical residues in foods of animal origin is extremely important to guarantee the quality of the product and, therefore, the health of the consumer. Macrocyclic lactones are veterinary drugs approved for use and have a maximum residue limit in food. National and international legislation includes these substances in their monitoring programs. The development and validation of an analytical method for the quantification in bovine muscle of abamectin, doramectin, eprinomectin, ivermectin and moxidectin, present in this group, was carried out. The method consists of a liquid-liquid extraction of the substances of interest with QuEChERS methodology, followed by analysis by high performance liquid chromatography coupled to mass spectrometry. To validate the method bovine muscles purchased from organic food producers were used to ensure that the matrices did not contain the compounds. Quantification technique using ivermectin-d2 as the internal standard was applied. Following the recommendations in protocols from Brazilian Ministry of Agriculture, Livestock and Supply and the European Union, tests were carried out to evaluate the selectivity of the method, establish the limit of quantification (LOQ), limit of detection (LOD), decision limit (CCa) and detection capability (CCb) and verify the parameters linearity, accuracy (recovery) and precision (repeatability and intermediate precision). The method developed proved to be selective, linear (r = 0.9524 to 0.9943; r2 = 0.9071 to 0.9886), accurate (recovery from 84.28% to 118.52%) and precise (repeatability: coefficient of variation from 0.17% to 21.66%; intermediate precision: coefficient of variation from 4.05% to 19.08%) and was validated with decision limit (CCa) and detection capability (CCb) of 20.205 and 20.409 ng g-1 for abamectin, 10.197 and 10.395 ng g-1 for doramectin, 100.228 and 100.456 ng g-1 for eprinomectin, 30,198 and 30,396 ng g-1 for ivermectin and 20,201 and 20,402 ng g-1 for moxidectin, respectively. The method presented a limit of quantification (LOQ) of 0.5 ng g-1 for the five macrocyclic lactones and a limit of detection (LOD) of 0.05 ng g-1 for all substances, except eprinomectin, which was 0.1 ng g-1, meeting the limits defined by government agencies with a considerable safety margin. The analytical method developed in the present dissertation proved to be suitable for the quantitative evaluation of the five macrocyclic lactones in bovine muscle using LC-MS/MS.