Exploiting the synergistic effect of β-cyclodextrin functionalized-multi-walled carbon nanotubes and Zn-MOF for the detection of endocrine-disrupting chemical methylparaben.

Background: The buildup of methylparaben (MP), a broad-spectrum antimicrobial preservative with endocrine-disrupting properties, in environmental sources, especially aquatic systems, has become a significant concern due to its adverse health effects, including allergic reactions, promoting the risk of developing cancer, and inducing reproductive disorders. Hence, introducing inexpensive and easy-to-use monitoring devices for rapid, selective, and sensitive detection and quantification of MP is highly desirable. In this context, electrochemical platforms have proven to be attractive options due to their remarkable features, such as ease of fabrication and use, short response time, and acceptable sensitivity, accuracy, and selectivity.

Results: In this regard, Zn-BTC metal-organic framework (MOF) and multi-walled carbon nanotubes (MWCNTs) functionalized with β-Cyclodextrin (β-CD) were utilized to modify the matrix of a carbon paste electrode (CPE). The morphological and electrochemical characteristics of β-CD-MWCNTs/Zn-BTC/CPE were evaluated using conventional material characterization techniques and electroanalytical methods. The sensor exhibited two linear current responses in concentration ranges of 0.01 mM-0.3 mM and 0.3 mM-6 mM. The limit of detection (LOD) and limit of quantification (LOQ) were calculated to be 3.8 μM and 11.5 μM, respectively. The device demonstrated excellent selectivity, repeatability, reproducibility, and stability over two weeks. Evaluating its applicability in real samples, including personal care products, tap and river water, and human blood serum, achieved recoveries in the range of 96.25 %-105 %, proving its reliability in environmental and industrial applications.

Significance: Overall, the proposed modified graphitic platform is not only a cheaper and more easily fabricable and applicable option for MP detection compared to other reported conventional and electrochemical devices but also demonstrates exceptional selectivity and satisfactory sensitivity among various reported electrochemical sensors. In addition, the developed electroanalytical tool can be employed for MP measurement in a broader range of real sample matrixes compared to alternative electrochemical platforms.