Synthesis and Characterization of a Molecularly Imprinted Silica Gel Sorbent for the On-Line Determination of Trace Sudan I in Chilli Powder through High-Performance Liquid Chromatography

摘要

A highly selective imprinted polymer was synthesized by a surface molecular imprinting technique in combination with a sol-gel process. The imprinted polymer was evaluated by FT-IR and static and kinetic adsorption experiments. The results showed that the imprinted sorbent exhibited good recognition and selective ability, offered a faster kinetics for the adsorption and desorption of Sudan I than the non-imprinted sorbent, a saturated binding capacity (Q_(max)) that reached 33.47 mg g~(-1). The prepared sorbent was applied for the determination of trace Sudan I through on-line solid-phase coupled with high-performance liquid chromatography (SPE-HPLC). With a loading flow rate of 1.5 mL min~(-1) for sampling 50 mL, an enrichment factor of 1266 was achieved. The detection limit (S/N = 3) was 1.2 ng L~(-1), and the peak area precision (RSD) for five replicate detections of 0.01 mu g L~(-1) Sudan I was 3.66%. The Sudan I in the chilli powder from the local market was determined at three levels (0.25, 0.5, and 1.0 ng g~(-1)) with recoveries ranging from 80.31 to 94.02%.