Molecularly imprinted solid-phase extraction for determination of tilmicosin in feed using high performance liquid chromatography

A simple, sensitive and reproducible molecularly imprinted solid-phase extraction (MISPE) coupled with high performance liquid chromatographic method was developed for monitoring tilmicosin in feeds. The polymers were prepared using tylosin as mimic template molecule, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking monomer, and chloroform as a solvent by bulk polymerization. Under the optimum MISPE conditions, the novel polymer sorbent can selectively extract and enrich tilmicosin from variety of feeds. The MISPE cartridge was better than non-imprinted, C₁₈ and HLB cartridges in terms of both recovery and precision. Mean recoveries of tilmicosin from five kinds of feeds spiked at 1, 10 and 50 mg kg⁻¹ ranged from 76.9% to 95.6%, with intra-day and inter-day relative standard deviation less than 7.6%. The linearity was ranged from 1.0 to 100 mg L⁻¹ for matrix standard solution (r = 0.9990). The limit of detection was approximately 0.35 mg kg⁻¹ and the limit of quantification was approximately 0.98 mg kg⁻¹. There was cleaner chromatogram by using MISPE than C₁₈ and HLB SPE.