Sensitive Detection of Trace Hydrogen Peroxide via Dual-Emissive Electrochemiluminescence from a Luminol/Porphyrin System: Comprehensive Innovative Experiments on Analytical Instruments for Undergraduates

Abstract

Owing to factors such as poor water solubility of luminol and the instability and easy decomposition of hydrogen peroxide (H 2 O 2 ), the accuracy and sensitivity of the detection of H 2 O 2 through the luminol electrochemiluminescence (ECL) system are limited. Herein, we propose a water-soluble dual-emissive ECL system using luminol and 5,10,15,20-tetrakis(4carboxyl)phenyl porphyrin (TCPP) to form a self-assembly (SA-luminol/TCPP). The new analysis system requires no-additional coreactant and can effectively reduce the interference of additives to the system. TCPP and luminol could enhance respective ECL signals and act as the internal standard method between each other in practical detection. Finally, the ratiometric SA-luminol/TCPP ECL for H 2 O 2 detection exhibited a linear range of 0.05 to 100 μM and a low detection limit of 0.039 μM (S/N = 3). This innovative experiment was designed for senior undergraduate students majoring in chemistry, materials, environment, and other fields as an extension of their training in comprehensive chemistry experiments. This experiment contains knowledge related to the synthesis of self-assembled materials, ECL, and the principles of using analytical instruments. Integrating this experiment into undergraduate teaching will (1) enable students to understand the importance of H 2 O 2 and its concentration in life activities; (2) stimulate students' development of innovative analytical methods that meet practical detection of H 2 O 2 ; (3) familiarize students in the exploration and optimization of the process of detection methods with methodical and rigorous scientific methods; (4) improve students' understanding of the advantages of ECL analysis and ratiometric detection, thereby enhancing their practical skills, by exploring innovative reaction methods.