Layer-by-Layer nanostructured films of magnetite nanoparticles and polypyrrole towards synergistic effect on methylparaben electrochemical detection

The sustained use of cosmetics, hygiene products and medicines containing methylparaben (MeP) can be related to cases of cancer in women and children, which is why it is important to develop simple ways to monitor this compound. Gold electrodes were modified with Layer-by-Layer (LbL) films of magnetite nanoparticles (MNP) and polypyrrole (Ppy) for electrochemical determination of MeP. To investigate the synergistic effect between the MNP and Ppy, three different LbL architectures were tested: multilayers of Ppy with an conventional polycation poly(allylamine hydrochloride) - Au/(PAH/Ppy)(3), MNP with a conventional polyanion poly(vinyl sulfonic acid)- Au/(MNP/PVS)(3) and the hybrid composite film Au/(MNP/Ppy)(3). The highest oxidation current and lowest oxidation potential were achieved by the Au/(MNP/Ppy)(3) electrode in a range up to 131.4 mu mol L-1 with a limit of detection of 9.95 x 10(-8) mol L-1. The performance of the electrochemical sensor was statistically investigated by the Miller-Miller method demonstrating accuracy comparable to an analytical method (capillary electrophoresis). MeP was determined in urine, breast milk and cosmetic with recovery values varying from 84.0% to 113.3%.