Simultaneous Determination of Zoalene and Its Metabolite in Chicken Muscle and Liver by SPE and UPLC–MS-MS

Abstract

This paper presents an analytical method for the simultaneous determination of zoalene and its metabolite 3-amino-5-nitro-o-toluamide (3-ANOT) in chicken muscle and liver by solid phase extraction and UPLC–MS-MS operated in the positive and negative ionization switching mode. Samples were extracted with phosphate buffer solution and purified with OASIS^™ HLB cartridge after pH adjustment. The determination was carried out using UPLC–MS-MS on a Waters Acquity BEH C₁₈ column with 0.1% formic acid in water/acetonitrile as mobile phase with gradient elution. The linearity of the analytical response across the studied range of concentrations (2.0–1,000 μg L⁻¹) was excellent, obtaining correlation coefficients higher than 0.999. Matrix effects had been investigated for zoalene and 3-ANOT. Recovery studies were carried out on spiked chicken muscle and liver blank samples, at four concentration levels (50, 1,500, 3,000, and 4,500 μg kg⁻¹ for chicken muscle and 50, 3,000, 6,000, and 9,000 μg kg⁻¹ for chicken liver) performing six replicates at each level. Mean recoveries of 77.9–94.2% with CVs of 3.2–8.7% were obtained. The method demonstrated to be suitable for the simultaneous determination of zoalene and 3-ANOT in chicken tissues.