Indirect Competitive Chemiluminescent Enzyme Immunoassay Method for Determination of Dimethyl Phthalate in Soy Sauce and Liquor / 分析化学

ABSTRACT

4-Amino dimethyl phthalate as the hapten was coupled to carrier protein and then used to immunize New Zealand rabbits. Polyclonal antibody which showed specific binding to dimethyl phthalate ( DMP) was thus obtained, and on the basis of this, an indirect competitive chemiluminescent enzyme-linked immunoassay ( icCLEIA ) was developed. The experimental parameters of icCLEIA were optimized as follows the concentration of coating antigen was 50 μg/L, the primary antibody concentration was 92. 5 μg/L, the secondary antibody concentration was 1μg/mL, distilled water (pH 6. 0) was used as diluent solution and the competitive reaction time was 40 min. Under the optimal conditions, the icCLEIA exhibited a linear working range from 0. 74μg/L to 30. 32μg/L with the limit of detection of 0. 29μg/L. The cross-reactivity of thirteen structural analogues was lower than 5%. The recovery of DMP from spiked liquor and soy sauce samples ranged from 80 . 2% to 116 . 0% and the average RSD was less than 3 . 6%. The detection results of the spiked liquor and soy sauce samples were consistent with those by standard gas chromatography-mass spectrometry method. The developed icCLEIA method exhibited a practical potential for detecting DMP residue in food samples.