Immunological strip sensor for the rapid determination of niacin in dietary supplements and foods

Abstract

Herein, four haptens of niacin (Vitamin B3, VB3) were designed, and after a series of experiments, it was concluded that hapten D had the best immune effect. To avoid false positives in the detection of real samples, a monoclonal antibody (mAb) against VB3 was prepared by a matrix effect-enhanced mAb screening method. The concentration of the inhibition rate reaching 50% (IC₅₀) was 603.41 ng mL⁻¹ and the limit of detection (LOD) using an indirect enzyme-linked immunosorbent assay (ic-ELISA) was 54.89 ng mL⁻¹. A lateral flow immunochromatographic assay (LFIA) based on gold nanoparticles was established to detect the concentration of VB3 in compound vitamin B tablets and infant formulas, with a visual LOD of 5 μg mL⁻¹. Using a handheld reader, the quantitative LOD was calculated to be 0.60 μg mL⁻¹. The contents of the compound vitamin B tablets and infant formulas were also verified by liquid chromatography. Therefore, the LFIA developed in this study can be applied to the specific identification and rapid detection of niacin in nutritional dietary supplements, thus meeting the market's demand for efficient niacin detection methods.