Polyaniline functionalized CoAl-layered double hydroxide nanosheets as a platform for the electrochemical detection of carbaryl and isoprocarb.

The preparation of the polyaniline/CoAl-layered double hydroxide composite (PANI/CoAl-LDH) is presented by ultrasonic mixing the uniform PANI- and CoAl-LDH-building blocks, both of which are synthesized in a microemulsion system. Due to the improved surface area, increased adsorptive and catalytic sites, and enhanced conductivity, the PANI/CoAl-LDH-modified glassy carbon electrode (GCE) delivers rapid electron-transfer and mass-transfer between the substrate electrode and analytes. Consequently, PANI/CoAl-LDH/GCE demonstrates outstanding electrocatalytic activity toward carbaryl and isoprocarb with good selectivity, stability, and reproducibility. The amperometric sensor gives rise to a wide linear range of 0.1 ~ 150 μM for both carbaryl and isoprocarb at 0.19 and 0.39 V (vs. SCE), respectively. Their limits of detection are respectively 6.8 and 8.1 nM. This sensor is successfully used for the determination of carbaryl and isoprocarb pesticides in real vegetable samples with a relative standard deviation below 4%.