MIL-101/GO Coated Stir Bar for SBSE to Determine Azo Dyes in Water Samples by UV–Vis Spectrophotometric Method

A composite of chromium (III) terephthalate metal-organic framework and graphene oxide (MIL-101/GO) coated stir bar was prepared by sol–gel technique for the first time and was employed for stir bar sorptive extraction (SBSE) of trace azo dyes amaranth, sunset yellow and carmine from water samples followed by UV–Vis spectrophotometric detection. A MIL-101/GO coating was first created on the glass bar surface. MIL-101/GO and MIL-101/GO coated stir bars were characterized. The enrichment factors of azo dyes by SBSE have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimal conditions, a method for determination of trace amount of azo dyes was setup, and the detection limits of amaranth, sunset yellow and carmine were 2.3 ng/mL, 1.7 ng/mL and 1.6 ng/mL. The proposed method was successfully applied for the analysis of the three azo dyes in water samples.