HPTLC-Densitometry Determination of Riboflavin Fortified in Rice Noodle: Confirmed by SERS-Fingerprint

This paper presented a facile and efficient HPTLC method for quantifying riboflavin fortification in rice noodle that was a staple food popular in Asian countries. After high-throughput separation on silica gel plates with methanol/ethyl acetate/triethylamine (3/7/1, v /v/v) as the mobile phase, the obtained results were analyzed by fluorescence densitometry (mercury lamp, 360 nm excitation wavelength in combination with K400 optical filter). Quantification in this way offered high linearity ( R 2  = 0.9998 within 10–80 ng/band) and precision (RSD < 5.2%), adequate detectability (LOD = 0.1 and LOQ = 0.3 mg/kg), and accuracy (spike-recovery rates within 91.4–105.1%, RSD < 8.1%). While yielding good comparison to conventional HPLC detection, the developed quantification featured superiorly high efficiency. Apart from that, the separation results were further evaluated by SERS. By jointly using sodium borohydride reduced AgNPs as the active substrate and 633 nm incident laser wavelength, the developed HPTLC-SERS detection gave clear and sensitive fingerprint-like proof which enabled unambiguous confirmation by visual inspection. Balancing well between simplicity, detectability, efficiency, and reliability, the proposed method exemplarily shown the promising applicability of HPTLC as a versatile tool in food analysis.