In this work, an electrochemical sensor was established for the detection of folic acid based on Ni-BTC (BTC = benzene-1,3,5-tricarboxylic acid) metal-organic framework (MOF) modified screen-printed electrode (SPE). Electrochemical techniques (cyclic voltammetry (CV), differential pulse voltammetry (DPV), linear sweep voltammetry (LSV) and chrono­ampere­metry (CHA) were used for the detection of folic acid at Ni-BTC MOF modified SPE. The results indicate that the as-prepared sensor has a good electrocatalytic effect on the detection of folic acid. This electrochemical sensor showed a dynamic linear response range from 0.08 to 635.0 µM and the detection limit was estimated to be 0.03±0.001 µM. Moreover, the feasibility of Ni-BTC MOF/SPE sensor to detect folic acid in real samples was also evaluated by the standard addition method.

The current work aimed to fabricate a screen-printed graphite electrode (SPGE) modified by MnO2 nanorods (MnO2 NRs) for sensing hydrazine. Thus, a facile protocol was adopted to construct the MnO2 nanorods that were subsequently applied to modify the SPGE surface directly. As-synthesized MnO2 NRs/SPGE sensor exhibited a strong sensing behavior towards the hydrazine, with a large peak current and small oxidation potential. This electrochemical sensor in the optimized conditions to detect the hydrazine possessed a low detection limit (0.02 μM), a broad linear dynamic range (0.05–275.0 μM) and an admirable sensitivity (0.0625 μA μM-1). The sensor applicability was practically estimated in real water samples, which revealed successful recovery values.