Development of metal complex imprinted solid-phase microextraction fiber for 2,2'-dipyridine recognition in aqueous medium

In this paper, a novel metal complex imprinted polymer (CIP) coated solid-phase microextraction (SPME) fiber was prepared which could recognize the complex template Cu(OAc)₂(2,2′-dipyridine)] in aqueous medium. The saturating adsorption capacity of CIP-coated fiber was 2.2 and 2.6 times greater than those of molecularly imprinted polymer (MIP) coated fiber and nonimprinted polymer (NIP) coated fiber, respectively. Extraction conditions that influenced the recognition performance of CIP-coated fiber were investigated including pH, extraction solvent, metal ion species, etc. The ligand selectivity was also evaluated and discussed. The results demonstrated that CIP-coated fiber had better binding affinity for 2,2′-dipyridine compared to its structure analogues. The recognition ability of CIP coating was stable and effective in aqueous medium while MIP coating showed weak imprinting effect due to disturbance from protic solvent. 2,2′-dipyridine extracted by CIP-coated fiber using HPLC/UV detection resulted in a linear range of 10-200 μg/L with a detection limit of 2.0 μg/L. The proposed method was successfully applied to the analysis of 2,2′-dipyridine in spiked tap water, laboratory wastewater and human urine samples with recoveries 80.3-103.3% and RSDs 5.5-8.9%.