Highly selective electrochemiluminescence enhanced detection of ascorbic acid in tablets and beverages utilizing...

A novel electrochemiluminescence (ECL) enhanced method for sensitive, selective and accurate ECL detection of ascorbic acid (AA) is developed using tris (2,2'-bipyridine) ruthenium (II) (Ru(bpy)₃²⁺) embedded into zirconium-based metal-organic frameworks (Ru(bpy)₃²⁺@UiO-67 MOFs). AA is oxidized by cerium ion (Ce⁴⁺) into dehydroascorbic acid (DHA) and hydrolyzed into 2,3-diketogulonic acid (DKG). The oxidation product DKG has α-keto acid structure and can form acyl radical, which enhances the ECL of Ru(bpy)₃²⁺@UiO-67 MOFs nearly 220 times. Therefore, AA is used as an efficient ECL co-reactant of Ru(bpy)₃²⁺@UiO-67 MOFs and applied in highly sensitive ECL enhanced detection of AA from 0.1 μM to 100 μM with a limit of detection of 29 nM. More importantly, this method also has high selectivity in AA detection toward other common ions, substances with similar structure to AA and some reducing substances owing to specific α-keto acid structure of the oxidation product DKG of AA. It achieves ECL enhanced detection of AA in tablets, chewable tablets and beverages.