Simultaneous determination of some coccidiostat antibiotics in food by liquid chromatography tandem mass spectrometry (LC-MS/MS)

Coccidiostats (anticoccidial antibiotics) are veterinary drugs widely used for the prevention and treatment of coccidiosis, especially in poultry farming. The illegal use of anticoccidial antibiotics, in the wrong dosage and duration, can lead to antibiotic residues in animal products and harm the health of consumers. In this study, a highly sensitive and accurate liquid chromatography-tandem mass spectrometry method was developed for the simultaneous analysis of anticoccidial antibiotics (diclazuril, nicarbazin, robenidin and salinomycin) in food. Samples were extracted using the QuEChERS method with acetonitrile (ACN) as the extraction solvent and cleaned with C18 adsorbent. The cleaned extracts were analyzed on an LC-MS/MS system with a C18 reversed-phase chromatography column (2.1 x 150 mm, 3.5 µm) and corresponding pre-column. The mobile phase used was 0.1% HCOOH in water and methanol (MeOH), the flow rate was 0.5 mL/min. The method had good specificity, the linear range was established in the range of 10-100 ng/mL, the correlation coefficient R2 > 0.998. The method recovery was in the range of 81-109% and the relative standard deviation (RSD%) was in the range of 1.77-10.13% for milk and meat samples. The limit of quantification and limit of detection of the method for four coccidiostat antibiotics were 3.0 µg/kg and 10 µg/kg, respectively. The method was applied to analyze the content of these four antibiotics in 31 food samples (meat and meat products, milk and dairy products) randomly purchased in Hanoi. The results did not detect four coccidiostat antibiotics in all 31 samples, initially showing that the residual contamination of coccidiostat antibiotics is basically safely controlled.