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 MnO-modified electrode that responds linearly to hydrogen peroxide (HO) from 0.16 M to 3.26 M. The electrode potential drops when the HO solution is spiked with catalase or catalase-producing microorganisms that decompose HO. The sensor is responsive to different bacteria and their catalase activities. The electrochemical sensor exhibits a lower limit of detection (LOD) for at 11 CFU/ml, at 12 CFU/ml, and at 23 CFU/ml. The sensor shows high sensitivity at 3.49, 3.02, and 4.24 mV/cmdec for , , and 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.