SAMPLE PREPARATION, EXTRACTION PROCESSES AND CLEANUP PROTOCOLS FOR THE ANALYSIS OF ANTIMICROBIAL DRUGS IN MILK BY LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY

Gjylai ALIJA, Zehra HAJRULLAI- MUSLIU, Sihana AHEMTI-LIKA, Edita ALILI-IDRIZI, Lulzime BALLAZHI, Drita YZEIRI- HAVZIU, Arlinda HAXHIU-ZAJMI, Dorentina BEXHETI, Arijeta SHABANI, Merita DAUTI, Nexhibe NUHII

Abstract

Antimicrobial drugs are used as chemotherapeutic agents for treatment, prophylactic medication, growth promoters, and the improvement of feed efficiency. Indiscriminate use of these drugs may leave residues in milk, which could pose a potential threat to human health and have undesirable effects on consumers, including allergic or toxic reactions, carcinogenic effects, bacterial resistance, and imbalance of the gut microfloraTo guarantee the safety of food products as well as public health, monitoring the levels of antimicrobial residues is necessary. The sample preparation, extraction of different physicochemical residues of milk, preconcentration of the extract, and elimination of any matrix interferences that may affect the overall performance of the analytical methods. SPE extraction with an Oasis HLB column is one of the most commonly used techniques for sample preparation and provides an effective and repeatable method for the selective concentration of target analytes in complex matrices. Different variations of this method, including acetonitrile, methanol, and acetonitrile: methanol (50:50), 20% trichloroacetic acid, and McIlvaine buffer, were optimized. According to the obtained results, the prescribed criteria for the analytical yield are met only by the extraction method using 20% trichloroacetic acid and Na2EDTA-Mcllvaine buffer. Chromatographic separation of analytes was achieved on a Kinetex®C18 column and provided satisfactory resolution within the shortest run time. The ESI positive ionization was promoted, and the detection of the compounds was improved with the acidic mobile phase. After optimization of chromatographic conditions, MS/MS conditions, and extraction procedures, the LC-MS/MS method was validated according to the criteria of Commission Decision 2002/657/EC.

Pages: 202 - 213