Combined microextraction by packed sorbent and high-performance liquid chromatography–ultraviolet detection for rapid analysis of ractopamine in porcine muscle and urine samples

A method for rapid analysis of ractopamine in porcine muscle and urine was developed and validated. The method was based on combined of microextraction by packed sorbent (MEPS) and high-performance liquid chromatography with ultraviolet detection (HPLC–UV). Parameters of the MEPS procedure affecting extraction efficiency were optimised. Optimum extraction conditions were 100 μL of sample in five extraction cycles and sampling time of <3 min. Compared with solid-phase extraction, the MEPS procedure required less extraction time, sample volume and consumption of organic solvents. The method demonstrated high linearity within 0.01–2 μg/mL for porcine muscle and urine samples (R2 > 0.9985). Accuracies of muscle and urine analyses were 93.9–109.2% and 93.4–105.1%, respectively. Intra-day and inter-day precisions (RSD%) were lower than 11.8% for both analyses. The method was applied for rapid analysis of ractopamine in biological samples. The method was simpler and could be used to screen other β2-agonists in other extraction media.