Sensitive, Selective and Simultaneous Monitor of Multiple Heavy Metals in Environment Using a Low-Cost MIL-53(Fe)/Ag₂CrO₄ Modified GCE Sensor

Due to the strong toxicity of heavy metal ions to public health and the environment, it is a great challenge to develop a method for ultra sensitive capture and determination of heavy metal ions effectively. Herein, a novel heterostructure composite (MIL-53(Fe)/Ag 2 CrO 4 , named MA(1:x)) was prepared by a simple method successfully. MA(1:x) modified GCE was applied to detect heavy metals ions simultaneously. Significantly, the designed MA(1:1)/GCE sensors performed outstanding detection performances. The wide ranges of 7.49 ∼ 320.00 μ mol l −1 and 7.49 ∼ 320.04 μ mol l −1 are obtained for Pb(II) and Cu(II) ions, respectively. The LOD of the MA(1:1)/GCE sensor was determined to be 27.40 nmol l −1 (5.68 ppb) for Pb(II) and 86.96 nmol l −1 (5.52 ppb) for Cu(II) ion simultaneously, which are lower than the allowable level of drinking water stipulated by the World Health Organization (WHO). Possible detection mechanism by the MA(1:1)/GCE was discussed. The MA(1:1)/GCE was successfully applied to monitor heavy metal ions locate in tap and river water. The recoveries are in the range of 93.86%–104.4%, which further proves the potential in analyzing real samples. Moreover, the MA(1:1)/GCE also showed excellent stability, selectivity, reproducibility. A novel method was provided to construct sensitive sensors for simultaneous analysis of different metal ions.