Electrochemical sensor detection of oxybenzone using an in situ molecularly-imprinted polypyrrole modified screen printed gold electrode

Abstract Oxybenzone (benzophenone-3), a common sunscreen ingredient, absorbs ultraviolet (UV) radiation to protect skin from sunburn, premature aging, and skin cancer. However, environmental concerns have arisen as oxybenzone has been detected in fish and linked to coral reef bleaching. In regions like Hawaii, USA, where oxybenzone use in sunscreens is banned, monitoring methods are needed. We developed an in situ electrochemically polymerized polypyrrole (PPy)-imprinted polymer on a screen-printed gold electrode (eMIP@PPy/SPGE) for the detection of oxybenzone. The imprinting factor (IF) was 2.04. Polymerization was optimized by the cyclic voltammetry (CV) scan cycles (40 cycles), template leaching solution (free-flow of 0.05 M methanolic hydrochloric acid, HCl), and template-monomer ratio (1:5). The electrode was characterized by electrochemical impedance spectroscopy (EIS), Fourier-transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FESEM) confirmed the presence of PPy on the SPGE. The calibration was linear (R 2 = 0.9913; y = 0.2549x + 2.1065) from 10.0 µM to 50.0 µM, with a detection limit of 13.2 µM. Spiked tap water samples yielded excellent recovery from 96 % to 102 %. The eMIP@PPy/SPGE proved to be a practical alternative method for detecting oxybenzone in water samples, with on-site and real-time monitoring.