Abstract: A flow injection-chemiluminescence (FI-CL) method based on molecular imprinting-solid phase extraction has been developed for the determination of maleic hydrazide (MH) in vegetables. This method was based on the enhancement effect of MH on chemiluminescence intensity of galangin-potassium permanganate-polyphosphoric acid system. A molecular imprinting polymer (MIP) was synthesized from the thermally initiated polymerization of MH as a template molecule, methacrylic acid as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker and azodiisobutyronitrile (AIBN) as an initiator and used to prepare a solid phase extraction column. Samples were subjected to solid phase extraction before CL assay. Under optimized conditions, relative CL intensity showed good linear relationship with MH concentration in the range from 5.0 × 10-5 to 3.0 × 10-2 mg/mL. The limit of detection of this method was 2.6 × 10-5 mg/mL (3σ). The precision (RSD) for 10 replicate determinations of a known concentration of MH (1.0 × 10-3 mg/mL) was 2.7%. In the determination of potato, onion and garlic by this method, average spike recovers of MH were in the range from 95.2% to 111.7% with RSD 1.8% for potato, 2.4% for onion and 2.1% for garlic, respectively.

Key words: maleic hydrazide (MH), molecular imprinting polymers (MIPs), solid phase extraction (SPE), flow injection (FI), chemiluminescence (CL), vegetables