Abstract:Phthalate ester plasticizer, a type of environmental hormone that is toxic to reproductive systems, has become a serious health threat because of its illegal transport and addition into foods intended for human consumption. Thus, development of an in situ testing method for the rapid detection of the plasticizer is essential. Herein, a colloidal gold-labeled immunochromatographic test paper method was developed for the rapid detection of dimethyl phthalate (DMP). To prepare the gold-labeled antibodies, anti-DMP polyclonal antibodies were labeled with colloidal gold prepared by the reduction of HAuCl4 using trisodium citrate. The chessboard method and the single-factor test were used to determine the optimal coating concentration and secondary antibody concentration, which were revealed to be 3000 μg/mL and 1600 μg/mL, respectively. The antibody was diluted 1.4-fold. The limit of detection of the developed assay was 0.4 μg/mL, and the visual detection time was within 5 min. Cross-reaction experiments showed no interference from substances with similar structures, indicating the high specificity of the method. The results from strip testing of baijiu liquor were consistent with those from GC-MS. This proposed immunochromatographic assay is fast, simple, and reliable, providing a valid method for the rapid in situ detection of DMP in foods.
