Novel anodic and cathodic dual-emitting electrochemiluminescence ratiometric method for phenylglyoxylic acid detection using S2O82- and Ag-MOFs amplification strategy

Phenylglyoxylic acid (PGA) as styrene metabolite is an indicator of styrene occupational exposure. In this work, a novel anodic and cathodic dual-emitting electrochemiluminescence (ECL) ratiometric method for PGA detection is developed using persulfate (S2O82-) and silver metal organic frameworks (Ag-MOFs) amplification strategy. PGA can enhance anodic ECL intensity of Ru(bpy)32+/PGA system nearly 2 times and cathodic ECL intensity nearly 16 times. S2O82- and Ag-MOFs as co-reactant accelerators promote redox reaction of PGA and enhance ECL intensity. Ag+ can catalyze S2O82- to produce SO4·-, which can convert Ag+ to Ag2+. Furthermore, SO4·- can accelerate the transformation of Ag+ generating more Ag2+. Compared with Ru(bpy)32+ system, cathodic ECL intensity of Ru(bpy)32+/K2S2O8/Ag-MOFs/PGA system gets enhanced nearly 170 times and anodic ECL intensity gets enhanced nearly 6 times. First electro-reduction and then electro-oxidation using scanning potential direction of 0→-1.3 V→1.4 V→0 also simultaneously enhanced cathodic and anodic ECL nearly 2 times. Thus this ECL ratiometric method for PGA detection has high sensitivity with LOD of 0.8 nM and rapid response once PGA is added in an instant (several seconds). More importantly, anodic and cathodic dual-emitting improves selectivity and avoid interference in complex detection.