Determination of veterinary antibiotics in German poultry manure by ultrasonic assisted extraction and QuEChERS coupled with LC-MS/MS

• The method offers the fast quantification of antibiotics in a challenging matrix. • It covers a broad range of six structurally strongly different analyte groups. • The method showed a suitable performance according to the validation criteria. • The analysis of poultry manure showed residues from lincomycin and ciprofloxacin. • Antibiotic residues can enter biogas plants along with poultry manure in Germany. A fast and efficient analytical method for the quantification of antibiotic residues in poultry manure based on ultrasonic assisted extraction (UAE) and QuEChERS cleanup followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. It was successfully validated for amoxicillin, cefaclor, ciprofloxacin, clarithromycin, erythromycin, lincomycin, metronidazole and ofloxacin in terms of linearity, detection and quantification limit, recovery, intra-day and inter-day precision and matrix effect. The overall method performance showed good linearity and recoveries ranging between 80.6 % and 138.1 % with sufficient limits of quantification for the targeted analytes. The method was applied to eleven poultry manure samples. Lincomycin and ciprofloxacin were detected in eight of eleven samples. The results show that the developed fast and efficient method can be employed to analyze poultry manure samples. In addition, antibiotic residues can be found regularly in poultry manure samples. When used in biogas plants or as fertilizer, they can pose a risk to human health and the environment. The method also includes cefaclor, an antibiotic that has, to the best of our knowledge, not yet been analysed in poultry manure.