A composite of platinum nanoparticles and multiwalled carbon nanotubes modified electrode for sensitive and simultaneous detection of hydroquinone and methylparaben in cosmetic products

In this study, a glassy carbon electrode (GCE) was modified with a composite of platinum nanoparticles (PtNPs) and multiwalled carbon nanotubes (MWCNTs) to serve as a sensing platform for the simultaneous detection of hydroquinone (HQ) and methylparaben (MP). The GCE surface was modified using a simple drop-casting technique with a PtNPs/MWCNT composite, and the composite was subsequently characterized by UV–Vis and FTIR spectroscopy, XRD, FESEM-EDS, and TEM techniques. The highest sensitivity of the developed sensor was achieved when the optimum composition of PtNPs and MWCNT was 4:6 on the surface of the GCE. This phenomenon may be attributed to the synergistic interaction between PtNPs and MWCNTs, which enhances the conductivity of the modified electrodes. The synergistic effect in relation to the catalytic activity of PtNPs and the large electroactive surface area of MWCNT results in an enhanced electrocatalytic signal for sensing purposes. Concurrently, the analytical performance of PtNPs/MWCNT/GCE was investigated using the differential pulse voltammetry (DPV) technique, which showed a linear response for HQ and MP in the ranges of 5–200 μM and 50–500 μM, respectively. Moreover, this proposed sensor demonstrated a low limit of detection and good sensitivity for the simultaneous detection of HQ (0.4 μM and 1.8136 μA μM−1 cm−2) and MP (0.8 μM and 0.7076 μA μM−1 cm−2). Furthermore, the proposed sensor exhibited excellent stability, reproducibility, and good selectivity, with recovery values ranging from 97.9 % to 101.6 % for HQ and from 98.8 % to 103.3 % for MP. Thus, this proposed sensor has been applied for the simultaneous detection of HQ and MP in cosmetic products, showing good recovery values that emphasize its potential as a promising sensing platform for detecting contaminant compounds in cosmetic products.