Synthesis of MnO2 decorated mesoporous carbon nanocomposite for electrocatalytic detection of antifungal drug

Rapid measurement of bacterial contamination in water: A catalase responsive-electrochemical sensor

The present study describes the development of a potentiometric sensor for microbial monitoring in water based on catalase activity. The sensor comprises a MnO2-modified electrode that responds linearly to hydrogen peroxide (H2O2) from 0.16 M to 3.26 M. The electrode potential drops when the H2O2 solution is spiked with catalase or catalase-producing microorganisms that decompose H2O2. The sensor is responsive to different bacteria and their catalase activities. The electrochemical sensor exhibits a lower limit of detection (LOD) for Escherichia coli at 11 CFU/ml, Citrobacter youngae at 12 CFU/ml, and Pseudomonas aeruginosa at 23 CFU/ml. The sensor shows high sensitivity at 3.49, 3.02, and 4.24 mV/cm2dec for E. coli, C. youngae, and P. aeruginosa, respectively. The abiotic sensing electrode can be used multiple times without changing the response potential (up to 100 readings) with a shelf-life of over six months. The response time is a few seconds, with a total test time of 5 min. Additionally, the sensor effectively tested actual samples (drinking and grey water), which makes it a quick and reliable sensing tool. Therefore, the study offers a promising water monitoring tool with high sensitivity, stability, good detection limit, and minimum interference from other water contaminants.

Integration of Bismuth sulfide/functionalized halloysite nanotube composite: An electrochemical tool for diethofencarb analysis

Diethofencarb (DFC) is a fungicide used in agricultural fields and it's overe use makes a negative impact in the real-time environment. Here in this work, a semi-conductive urchin like Bismuth sulfide (Bi₂S₃) anchored with tubular structure functionalized halloysite nanotube (F-HNT) was hydrothermally synthesized and used for the electrochemical detection of DFC. Various analytical and microscopic techniques were used to analyze the structure, crystalline nature, and purity of the as-prepared F-HNT@Bi₂S₃. Moreover, the cyclic voltammetry technique was used to analyze the electrochemical studies of the F-HNT@Bi₂S₃ modified glassy carbon electrode (GCE). A high synergetic relationship between the Bi₂S₃ and F-HNT provides a large surface area and better detection of DFC. The amperometry i-t technique result shows that the prepared composite exhibits a wide linear range of 0.0053-526.62 μg L^-1, a low detection limit of 0.0032 μg L^-1, and very good stability over 2000 s. Notably, our proposed sensor can determine the DFC spiked tomato and water samples with a high recovery range and proven the viability for real-time analysis. Finally, all the above-mentioned study results prove that the F-HNT@Bi₂S₃ could be used as an electrochemical probe for the detection of DFC.