Stainless Steel Electrode for Sensitive Luminol Electrochemiluminescent Detection of H2O2, Glucose, and Glucose Oxidase Activity

Electrogenerated chemiluminescence (ECL) application of stainless steel, a robust and cost-effective material, has been developed for the first time. Type 304 stainless steel electrode shows appealing ECL performance in the luminol-H2O2 system. It enables the detection of H2O2 with a linear range from 1 to 1000 nM and a limit of detection of 0.456 nM [signal-to-noise ratio (S/N) = 3]. The ECL method based on type 304 stainless steel electrode is more sensitive, more cost-effective, and much simpler than other ECL methods reported before. Because the stainless steel electrode has excellent performance for H2O2 detection and H2O2 participates in many important enzymatic reactions, applications of stainless steel electrode-based ECL for detection of enzyme activities and enzyme substrates were further investigated by use of glucose oxidase (GODx) and glucose as representative enzyme and substrate. The concentrations of glucose and the activity of GODx were directly proportional to ECL intensities over a range of 0.1-1000 μM and 0.001-0.7 units/mL with limits of detection of 0.076 μM and 0.00087 unit/mL (S/N = 3), respectively. This method was successfully used for determining glucose in honey. Because of their remarkable performance and user-friendly features, stainless steel electrodes hold great promise in various electroanalytical applications, such as biosensing, disposable sensors, and wearable sensors.