Microfabricated multiplexed sensor for the determination of undisclosed aphrodisiac medications in herbal products

The prevalence of herbal aphrodisiacs adulterated with undeclared pharmaceuticals poses significant health risks, necessitating rapid, on-site detection methods. This work presents a novel, multiplexed potentiometric sensor for the simultaneous detection of sildenafil citrate (SIL) and dapoxetine HCl (DPX) in complex herbal matrices. The sensor utilises microfabrication for portability and incorporates molecular recognition elements such as a molecularly imprinted polymer for SIL and calix[8]arene for DPX-to achieve high selectivity. The sensors exhibited Nernstian responses with slopes of 54.91 and 56.54 mV per decade for SIL and DPX, respectively, across a wide linear range (1.0 × 10^-7 to 1.0 × 10^-2 mol L^-1) and low detection limits (9.8 × 10^-8 and 5.1 × 10^-8 mol L^-1). The host-guest interactions validated by molecular mechanics calculations were further supported experimentally by the significantly enhanced selectivity coefficients. The mutual interference of studied drugs was reduced by 1.5 to 2.5 orders of magnitude. The sensor successfully analyzed commercial herbal products (Ginkgo biloba, Herbal Viagra, Chinese herbal medicine), detecting an undisclosed SIL contamination in one sample and demonstrating excellent accuracy (95.0-105.1% recovery) for spiked samples. Meeting key WHO "ASSURED" criteria, this user-friendly, cost-effective platform offers a robust tool for safeguarding consumer health by enabling the rapid screening of adulterated herbal supplements.