Simultaneous quantitation of nicotinamide riboside and nicotinamide in dietary supplements via HPTLC–UV with confirmation by online HPTLC–ESI–MS

The identification and quantitation of nicotinamide riboside (NAR) and its main related compound (nicotinamide) were achieved using high-performance thin-layer chromatography (HPTLC)–ultraviolet (UV) densitometry with confirmation by online electrospray ionization (ESI)–mass spectrometry (MS). As the stationary phase, HPTLC Si 60 F 254 glass plates were employed; the mobile phase was ethanol–1 M ammonium acetate–formic acid (7:1:0.1, v / v / v ). No derivatization was applied, and UV densitometry was performed in the absorbance mode (270 nm). The method was validated by specificity, linearity, accuracy, precision, and robustness.