Determination of sodium benzoate in food products by fluorescence polarization immunoassay

摘要

A rapid and sensitive fluorescence polarization immunoassay (FPIA), based on a polyclonal antibody, has been developed for the detection of sodium benzoate in spiked samples. The immunogen and fluorescein-labeled analyte conjugate were successfully synthesized, and the tracer was purified by TLC. Under the optimal assay conditions, the FPIA shows a detection range of 0.3-20.0 μg mL~(-1) for sodium benzoate with a detection limit of 0.26 μg mL~(-1) in the borate buffer. In addition, the IC_(50) value was 2.48 μg mL~(-1), and the cross-reactivity of the antibodies with ten structurally and functionally related analogs were detected respectively. Four kinds of food samples (energy drink, candy, ice sucker, RIO~(?) cocktail) were selected to evaluate the application of FPIA in real systems. The recoveries were 96.68-106.55% in energy drink; 95.78-100.80% in candy, 86.97-102.70% in ice sucker, and 103.58- 109.87% in benzoate contained sample RIO~(?) cocktail, and coefficients of variation of this method were all lower than 11.25%. Comparing with the detection results of HPLC, the developed FPIA has comparative performance in the real sample determination. The results suggest that the FPIA developed in this study is a rapid, convenient and simple method, which is suitable to be used as a screening tool for homogeneous detection of sodium benzoate in food products.