A Sensitive Dissolved Oxygen Sensor Based on a Charge-Transfer Complex Modified Electrode

A charge-transfer complex was modified on the graphite paste electrode for making a sensitive dissolved oxygen sensor. It was composed of copper with two ligands of phenanthroline and 1,2-dicyano-1,2-dithiolethane. Because of the low redox potential of the core ion and the pull and repulsive effect from the ligands, the redox of modified complex toke place under lower potential and it could selectively catalyze the reduction of dissolved oxygen. The slope of the chronocoulometric curve of the sensor proportionally responded on the content of dissolved oxygen from 0 to 16 mg/L within 1–2 seconds. It was applied to detect the dissolved oxygen in tape water and the campus river for 3.0mg/L and 5.1mg/L. This sensor responded the dissolved oxygen with high selectivity, wide linear range, high accuracy, excellent stability and fast speed. It’s very possible to act as a practical sensor for the detection of dissolved oxygen in field.