Curcumin graphite pencil electrode modified with molybdenum disulfide nanosheets decorated gold foams for simultaneous quantification of nitrite and hydrazine in water samples.

A non-enzymatic sensor based on a curcumin modified pencil graphite electrode, loaded with molybdenum disulfide nanosheets decorated gold foam, was constructed. Herein, the electrochemical deposition strategy was adopted throughout the sensing platform design stepwise. The electroactivity of the pencil electrode platform enables sensitive simultaneous quantification of hydrazine and nitrite where the respective working potentials typically are at + 0.2 V for hydrazine and + 0.75 V for nitrite (both vs. Ag/AgCl, saturated KCl). It is shown that the resulting sensor demonstrates excellent analytical performances in terms of limits of detection (18.3, 21.7 nM), sensitivities (0.051, 0.061 μA μM-1), and reproducibility standard deviations (RSD) of 3.1 and 2.7% for hydrazine and nitrite, respectively. Furthermore, long term stability studies showed that the electrodes exhibited an effectively unchanged response after some 30 days. The sensor was used to analyze spiked samples of river water and industrial wastewater.