A composite nanomaterial of nicotinamide-TiO2 as a adsorbent in dispersive solid-phase extraction method for extraction azo dyes from foodstuffs

A porous nicotinamide-TiO 2 adsorbent was synthesized via a simple, green method. • The proposed adsorbent exhibited excellent extraction performance toward azo dyes. • The performance of nicotinamide-TiO 2 is comparable with a commercial WAX column. • The proposed adsorbent efficiently extracts azo dyes from complex food matrices. In this work, a porous nicotinamide-TiO 2 nanocomposite was successfully synthesized via a simple and green method, and employed as an effective dispersive solid-phase extraction (DSPE) adsorbent for the selective enrichment of azo dyes from food products. The adsorption was found to be pH-dependent (optimum at pH 3.0) and followed a monolayer chemisorption mechanism, with the affinity being attributed to a combination of Lewis acid–base interactions, electrostatic attraction, and π–π stacking. Under optimized DSPE-HPLC conditions, the nicotinamide-TiO 2 adsorbent achieved high adsorption capacities of 14.7, 12.5, and 19.6 mg g −1 for amaranth (AM), new coccine (NC), and tartrazine (TA), respectively. The developed method with nicotinamide-TiO 2 exhibits satisfactory linear ranges with correlation coefficients >0.999, high sensitivity (limits of detection: 0.17–0.21 mg L −1 ) and good precision (intra- and inter-day RSD <5.5%). In spiked tea beverage samples, the proposed method afforded recoveries ranging from 92.3% to 103.1% for AM, NC, and sunset yellow (SY), which were superior to those obtained with a commercial WAX column, while also exhibiting lower matrix effects. The paired t -test revealed the DSPE-HPLC with nicotinamide-TiO 2 is a reliable pretreatment method to extract azo dyes, as there is no significant difference ( p  > 0.05) between this adsorbent and the commercial WAX column. The method was successfully applied to determine azo dyes in tea beverages and carbonated drinks. Overall, DSPE-HPLC method using nicotinamide-TiO 2 was proven to has promising potential for application in determination azo dyes in food products. Download: Download high-res image (68KB) Download: Download full-size image