A highly sensitive electrochemical sensing platform based on Zn-CuGaO₂@CMK-3 signal amplification for simultaneous detection of the sunset yellow and tartrazine in foods

In this work, a highly sensitive electrochemical sensor based on Zn-doped copper gallium oxide@ordered mesoporous carbon (Zn-CuGaO₂@CMK-3) for signal amplification was successfully developed for the simultaneous detection of sunset yellow (SY) and tartrazine (TZ) in foods. Compared with CuGaO₂@CMK-3, Zn-CuGaO₂@CMK-3 offered enhanced conductivity and catalytic properties owing to the improved carrier density, which was beneficial to the electrooxidation of SY and TZ. Under the optimal testing conditions, the constructed Zn-CuGaO₂@CMK-3/GCE sensor offered a wide linear concentration range (0.25–100.00 μmol/L) for the detection of both SY and TZ. The limits of detection for SY and TZ were 0.044 and 0.059 μmol/L, respectively. Recovery experiments were performed in milk, white vinegar and biscuit samples, yielding satisfactory recoveries (82.70%–114.80%). Furthermore, the sensor was successfully applied to the determination of the SY and TZ residues in two kinds of carbonated drinks, and the results were nearly consistent with those detected by the high performance liquid chromatography (HPLC) method (P > 0.05).