A nonenzymatic approach for selective and sensitive determination of glycerol in biodiesel based on a PtRu-modified screen-printed edge band ultramicroelectrode

A nonenzymatic electrochemical method using PtRu-modified screen-printed edge band ultramicroelectrode has been developed for selective and sensitive detection of glycerol. It was based on the periodate oxidation of glycerol and the as-formed formic acid and formaldehyde was detected by the proposed electrochemical sensor in the gas phase. This approach simplified the two steps of sample preparation and detection into a 2-in-1 single step process. It also eliminated almost all of the interferants in the solution phase and hence resulted in a highly selective analysis of glycerol. The proposed approach improved the analytical performance of other electroanalytical methods for quantification of glycerol with a low detection limit of 0.51 mg L−1 glycerol (S/N = 3) and a wide linear range of 0.92–92 mg L−1. Especially, for monitoring free glycerol in biodiesel, no extraction of glycerol from biodiesel to eliminate organic interferents was required. The accuracy was evaluated using a spike-and-recovery assay to prove its applicability as a valuable tool for practical glycerol analysis.