Quantification of sorbic acid using the molecularly imprinted chemiluminescence method with rhodanine derivative

A novel molecular imprinting-chemiluminescence (MI-CL) method for the determination of sorbic acid (SA) was established, taking the molecularly imprinted polymer (MIP) as recognition material and a novel rhodanine derivative as chemiluminescence reagent. The MIP was prepared by a self-assembly technique with SA as template molecule, methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. It was found that 3-o-methoxyphenyl-5-(2'-sulfono phenylazo) rhodanine (2MORASP) significantly enhanced the luminescence intensity of the SA-potassium permanganate-hydrochloride acid system. The method was proved to be selective and sensitive. Under the optimized experimental conditions, the system exhibits an excellent linear relationship over the range of 3.0 x 10(-7)-6.0 x 10(-4) g mL(-1). The detection limit of the proposed method was 2.2 x 10(-8) g mL(-1). This method was successfully applied to the determination of SA in milk and fruit juice samples.