Solid-contact polymeric membrane ion-selective electrodes based on electrodeposited NiCo2S4 nanosheet arrays br

In situ growth of quasi-superhydrophobic porous NiCo2S4 nanosheet arrays with a one-step electrodeposition method was provided. A calcium ion-selective electrodes (Ca2+-ISE) was subsequently constructed by using the prepared NiCo2S4 as a solid contact layer. The proposed Ca2+-ISE exhibits a good Nernstian slope of 30.7 +/- 0.3 mV/dec and a detection limit of 1.6 x 10-7 M. Due to the large redox capacitance of 1.8 mF, the Ca2+-ISE based on NiCo2S4 nanosheet arrays shows a high potential stability of 1.9 +/- 0.5 mu V/h over 90 h. Excellent reproducibilities for the NiCo2S4-based Ca2+-ISEs can be obtained with the single batch and batch-to-batch E degrees standard deviations of 0.3 (n = 6) and 0.7 mV (n = 5), respectively. The NiCo2S4 nanosheet arrays have a large contact angle of 148 +/- 1.4 degrees, which effectively suppresses the formation of a water layer at the sensing membrane/NiCo2S4 interface