Electrochemical Sensor Based on MWCNT-CS/AuNPs-Modified Carbon Paste Electrode for Methyl Paraben Detection Mega Wijayanti Kusumadewi (a*), Henry Setiyanto (b)
Analytical Chemistry Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Indonesia
Abstract
Methyl paraben is widely used as a preservative in cosmetic and personal care products and has been identified as a potential Endocrine Disrupting Chemicals (EDC), raising concerns regarding its impact on human health and the environment. Therefore, analytical methods are required for the determination of methyl paraben in various matrices. In this study, an electrochemical sensor based on a multi-walled carbon nanotube-chitosan/gold nanoparticles (MWCNT-CS/AuNP)-modified carbon paste electrode (CPE) was developed for the detection of methyl paraben. The modified electrode was prepared by drop-casting an MWCNT-CS composite onto the CPE surface followed by electrodeposition of AuNPs. Cyclic voltammetry was conducted over a range of scan rates in ferri/ferrocyanide redox probe, and the electroactive surface area was estimated based on the Randles-Sevcik equation. The electroactive surface area increased from 6.22 square millimeters for the bare CPE to 18.27 square millimeters for CPE/MWCNT-CS/AuNPs, corresponding to an approximately 2.9 times larger surface area. Quantitative analysis was performed using linear sweep voltammetry over a concentration range of 1-1000 uM. Three linear ranges were obtained at 1-10, 10-100, and 100-1000 uM. The developed sensor exhibited a sensitivity of 1.20 uA/uM cm2, LOD of 0.506 uM, and LOQ of 1.688 uM. The selectivity of the sensor was evaluated in the presence of common cosmetic interferents, AA, HQ, and BHA. The sensor showed over 90% of its initial response even at a methyl paraben-to-interferent ratio of 1:100, showing good anti-interference performance. Furthermore, the electrode showed good storage stability, maintaining 87% of its initial response after 20 days of storage at room temperature. These results show that the MWCNT-CS/AuNP-modified carbon paste electrode provides a promising platform for the sensitive and selective electrochemical detection of methyl paraben.
