Nanostructured magnetic graphene oxide/UIO-66 sorbent for ultrasound-assisted dispersive solid-phase microextraction of food colorants in soft drinks, candies, and pastilles prior to HPLC analysis

Abstract

Direct quantitative determination of food colorants in commercial food products is challenging due to their trace concentration. In this work, the magnetic graphene oxide/UIO-66 sorbent was used in an ultrasound-assisted dispersive solid-phase micro-extraction (UA-DSPME) process for the pre-concentration of Tartrazine (TA), Sunset Yellow (SY), and Allura Red (AR) food colorants prior to their quantitative determination using high-performance liquid chromatography (HPLC) analysis. Plackett-Burman design (PBD) was used to statistically explore all extract independent variables, and response surface methodology (RSM) was used to optimize the key variables. Under ideal circumstances, the method showed superior analytical performance with limits of detection (LOD) less than 0.070, 0.281, and 0.150 ng mL−1, and limits of quantitation (LOQ) less than 2.318, 9.368, and 4.988 ng mL−1 for TA, SY, and AR colorants, respectively. Furthermore, the procedure was effectively implemented with an extraction time of 15 min per sample with recoveries ranging from 95.01 to 106.33 %. Analysis of the standard reference material and recovery trials (>95 % relative recovery with lower than 6 % relative standard deviations) after spiking a known quantity of analyte in actual samples were used to evaluate the developed method's accuracy. The current method's distinctive benefits include minimal extraction time, high recovery, acceptable limit of detection, high accuracy, and good reusability in the development of pre-concentration and quantitative measurement of food colorants at trace levels in commercial food items.