Synthesis and characterization of a novel molecularly imprinted polymer for simultaneous extraction and determination of water-soluble and fat-soluble synthetic colorants in chilli products by solid phase extraction and high performance liquid chromatography

A sorbent was synthesized and investigated for molecularly imprinted solid phase extraction (MISPE). Molecularly imprinted polymers (MIP) were synthesized via precipitation polymerization procedure, where 4-vinyl pyridine (4-VP) was used as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The imprinting effect of the MISPE was evaluated by elution experiments. The resulting MISPE showed high extraction selectivity to water-soluble and fat-soluble synthetic colorants. The determination of multi-residue for three kinds of water-soluble and six kinds of fat-soluble synthetic colorants in chilli products was also investigated by HPLC coupled with MISPE. The mean recoveries calculated by solvent calibration curve for water-soluble and fat-soluble synthetic colorants were from 72.1% to 95.6% for chilli spice and 72.1% to 92.3% for chilli powder. The decision limit (CCα) and the detection capability (CCβ) obtained for water-soluble and fat-soluble synthetic colorants were in the range of 1.2–1.6 and 1.9–2.4 μg kg⁻¹ in chilli spice and chilli powder. The resulting MISPE was successfully used off-line for the determination of nine kinds of synthetic colorants in chilli products.