A folic acid mini sensor based on the electrochemiluminescence of perylene tetracarboxylic acid on screen-printed carbon electrodes

A novel miniaturized electrochemiluminescence (ECL) sensor for folic acid detection was developed using perylene tetracarboxylic acid (PTCA) as a luminophore and potassium persulfate (K₂S₂O₈) as a co-reactant on screen-printed carbon electrodes (SPCEs). This is the first report to integrate PTCA-based ECL with disposable SPCEs for folic acid quantification. The sensor requires only 45 μL of the sample and operates optimally at -1.6 V (<i>vs.</i> Ag/AgCl) in a 0.1 mol L^-1 phosphate buffer (pH 9) containing 1.0 mmol L^-1PTCA and 30 mmol L^-1 K₂S₂O₈. Increasing folic acid concentrations resulted in a significant quenching of the ECL signal, yielding a linear response (<i>R</i>² = 0.99) in the range of 2.26-22.65 μmol L^-1. The detection and quantification limits were 0.34 and 1.13 μmol L^-1, respectively. The sensor demonstrated good repeatability (RSD = 3.46%), selectivity against potential interferents, and successful application to pharmaceutical and milk samples, with recoveries between 97 and 107%. These findings highlight the potential of the developed mini-ECL sensor as a practical tool for rapid and sensitive folic acid monitoring.