Stir bar sorptive extraction with a graphene oxide framework-functionalized stainless-steel wire for the determination of Sudan dyes in water samples
Novel graphene oxide framework (GOF)-modified stainless-steel wires (SSWs) were prepared for stir bar sorptive extraction (SBSE). Then, they were combined with a high performance liquid chromatography-ultraviolet (HPLC-UV) method for the determination of four Sudan dyes (G, I, II, and III) in lake water and fruit juice samples. A GOF composed of graphene oxide (GO) sheets covalently interconnected by 1,4-phenylene diisocyanate (PPDI) was used as the coating material for SBSE. To immobilize the GOF on the chemically resistant surface of the SSW, polydopamine and PPDI were used to functionalize the SSW and act as linkers. The prepared GOF-SSW was applied for SBSE and showed good extraction efficiency towards Sudan dyes under optimized conditions. GOF-SSW-based SBSE was coupled with HPLC-UV for determination of Sudan dyes in aqueous solutions. This method showed good linearity (1–200 ng mL−1 for Sudan G, Sudan I and Sudan II; 1–100 ng mL−1 for Sudan III), low limits of detection (0.15–0.3 ng mL−1) and good reproducibility (relative standard deviation ≤ 5.85%). The proposed method was applied to determine Sudan dyes in lake water and fruit juice samples, and showed good selectivity and good recovery (89.38–108.54%).