Investigation of the presence of nitroimidazole group drug residues using LC/MS/MS in raw milk consumed around Ankara

Nitroimidazoles are a group of drugs that are highly active against anaerobic bacteria and also against pathogens of protozoal infections. Their residues in animal products exhibit mutagenic and carcinogenic effects on humans. In this study, it was aimed to analyze the presence of residues of nitroimidazole group drugs in raw cow milk samples consumed in Ankara province with method validation for the determination of nitroimidazole and its metabolites by liquid-chromatography tandem mass spectrometry (LC/MS/MS) and to determine the possible residue risk status for both animal health and consumers with the findings obtained. Pretreatments with ethyl acetate and n-hexane were carried out to obtain the compounds from the milk samples before the analysis, and in the last part, the samples were treated with methanol-water mixture and injected into LC/MS/MS. Analytes were separated on a C18 column and mobile phase treatment with acetonitrile and formic acid in water. In the study, it was determined that the recoveries of nitroimidazole compounds were between 100.5-101.7, detection and measurement limits were between 2.22-2.37 µg/l and 2.66-3.12 µg/l, respectively, and CCα and CCβ values were between 2.21-2.34 µg/l and 2.35-2.58 µg/l, respectively. In addition, 60 raw cow milk samples collected from Ankara province were analyzed for the presence of nitroimidazole residues by LC/MS/MS and it was determined that the samples did not contain nitroimidazole residues as a result of the data obtained. As a result, it was observed that the method used for the determination of nitroimidazoles gave sensitive and accurate results, and that the raw milk offered for consumption did not pose a risk to consumer health in terms of nitroimidazoles.