Determination of trace Para Red residues in foods through on-line molecularly imprinted solid phase extraction coupled with high-performance liquid chromatography.

In this article, we prepared a novel imprinted polymer by a room temperature ionic liquid-mediated surface molecular imprinting technique in combination with a sol-gel process. This polymer was characterized by static and kinetic adsorption experiments and exhibited good recognition ability and offered fast kinetics for the adsorption of Para Red. A simple and sensitive analytical method, based on the coupling of molecularly imprinted solid phase extraction with high-performance liquid chromatography (HPLC), had been developed for determination of trace Para Red. With a loading flow rate of 0.42 mL min(-1) for 25 mL, an enrichment factor of 1061 was achieved. Under the selected experimental condition, the detection limit (S/N = 3) of Para Red was 6.6 ng L(-1), and the peak area precision (RSD) for 5 replicate detections of 0.15 microg L(-1) Para Red was 4.1%. The applicability of this method for determination of the blank chili sauce sample, spiked with Para Red at 5 to 25 ng g(-1) levels, was demonstrated, with recoveries ranging from 86% to 95%. In this paper, a simple and sensitive analytical method, based on the coupling of molecularly imprinted solid phase extraction with high performance liquid chromatography, had been developed for determination of trace Para Red. It was applied to the analysis of spiking Para Red in chili sauce sample with satisfactory recovery and repeatability. This proposed method has the potential to be used for monitoring the illegal addition of Para Red in foods in the future due to its simple, reliable, rapid, and excellent precision.