Determination of Nicotinic Acid in Food and Pharmaceuticals by a Simple and Rapid Fluorescence Polarization Immunoassay (FPIA)

Abstract

A simple and rapid fluorescence polarization immunoassay (FPIA) based on polyclonal antibodies is reported for the first time for the determination of nicotinic acid. First, six nicotinic acid analogues were coupled with fluorescein isothiocyanate isomer I (FITC) to obtain tracers. The influences of tracer structure on the performance of FPIA as well as the structure-activity relationships were explored. Subsequently, the tracer concentration and antibody dilution ratio on the performance of FPIA were investigated. For the optimal conditions, the detection range of FPIA was from 1.1 to 145.6 μg mL−1 and its IC20 value as the limit of detection (LOD) was 1.1 μg mL−1. The cross-reactivity of antibodies with common vitamins was evaluated. The intra-assay recovery was from 92.0% to 101.2% in food and tablets, with inter-assay recoveries between 92.0% and 103.8%. The developed FPIA provided good sensitivity and reproducibility and therefore provided efficient and economic screening for nicotinic acid in food and tablets.