Large Magneto-Current Effect in the Electrochemical Detection of Oxalate in Aqueous Solution

Herein, we first report an interesting observation of a large magneto-current (MC) of nearly 30% based on the electrochemical oxidation of oxalate in aqueous solution at room temperature. The large MC is ascribed to spin-dependent oxidation of oxalate. Both singlet and triplet radical pairs are generated during the electrochemical oxidation of oxalate. An applied magnetic field could accelerate the spin evolution of a singlet radical pair into its triplet state. The triplet radical pair has a much larger dissociation probability than the singlet radical pair because of the Pauli exclusion principle. Thus, enhancing the triplet yield could largely increase the oxidation rate of oxalate and generate significant MC. The significant MC effect provides a new approach to study spin evolution of radical pairs in electrochemical cells. Furthermore, an effective analytical method for oxalate determination can be developed based on the significant MC effect.