Electrochemical sensor based on polyoxometalate immobilized using a layer-by-layer assembly process to detect 2,4-dinitrophenylhydrazine

To develop an excellent electrochemical sensor for the detection of 2,4-dinitrophenylhydrazine (2,4-DNPH), which has become a primary organic pollutant in the environment and is greatly poisonous, four polyoxometalates (POMs) with different structures (H3PW12O40: PW12, K6P2W18O62: P2W18, K12.5Nal.5[NaP5W30O110]center dot 15H(2)O: P5W30, K28Li5H7P8W48 center dot 92H(2)O: P8W48) were chosen to investigate their sensing performance in solution and composite films towards the detection of 2,4-DNPH. The results indicated that the composite film containing P8W48 exhibited the best performance among the four POMs. The study focused on the effect of the layer number and solution pH on the sensing performance of the composite film containing P8W48, proving that the composite film with seven layers of P8W48 in pH 7 solution showed the optimal electrocatalytic activity for the reduction of 2,4-DNPH. Further, under the optimized conditions, the sensing performance of the P8W48-based composite film was evaluated by CV and i-t curves, giving a linear concentration range of 1 to 700 mu M with a low detection limit of 0.012 mu M. Moreover, the selectivity, stability, reproducibility and repeatability were examined, confirming that the developed sensor has good potential for determining 2,4-DNPH in the environment.

Automated summary

An excellent electrochemical sensor for the detection of 2,4-dinitrophenylhydrazine (2,4-DNPH) was developed using four different polyoxometalates (POMs) as sensing materials. The composite film containing P8W48 showed the best performance among the four POMs. The optimized composite film exhibited a linear concentration range of 1 to 700 μM with a low detection limit of 0.012 μM, and it also exhibited good selectivity, stability, reproducibility, and repeatability.