A cost-effective screen-printed electrochemical sensor enhanced with Printex L6 carbon and poly-L-cysteine for catechin detection in tea and water matrices

Author(s)

Oliveira, Igor G. S. ; Gallina, Fernando C. ; Bimbi Junior, Fausto E. ; Santos, Anderson M. ; Lanza, Marcos R. V. ; Barros, Willyam R. P.

• Document type: Journal article
• Source: Microchemical Journal; v. 209, p. 10-pg., 2025-02-01.

Abstract

This study developed a low-cost graphite screen-printed polyethylene-based electrode (SPPE) modified with carbon black and p-L-cysteine (p-L-Cys) for catechin (CAT) detection. The SPPE was modified with Printex L6 carbon - immersed in chitosan dispersion (PL6C@Chi), and p-L-Cys, which gave rise to the proposed SPPE/ PL6C@Chi/p-L-Cys sensor. The SEM images of the sensor revealed that the electrode had a high surface area covered by p-L-Cys polymeric film. The SPPE/PL6C@Chi/p-L-Cys sensor was characterized by increased hydrophobicity, as evidenced by its lower contact angle and higher electrical resistance compared to sensor without p-L-Cys. Differential pulse voltammetry was used for the detection of 4.0 x 10-5 mol L- 1 CAT in 0.10 mol L- 1 PBS at pH 7.0 and under a fixed concentration. The analytical curve was constructed in the concentration range of 5.00 x 10-9 to 1.00 x 10-4 mol L- 1, where a limit of detection of 2.52 x 10-9 mol L- 1 was obtained. The recovery analysis conducted on the samples of green and black tea and tap water using the proposed method resulted in high recovery rates- from 97.6 to 104.6 %. In addition, the interference analysis conducted using six different compounds showed no interference in the electrochemical detection of CAT. These findings show that the electrochemical technique developed in this study holds significant promise for CAT detection in environmental and tea samples and has great potential for practical applications in quality control. (AU)

• FAPESP's process: 23/14335-6 - Development of disposable electrochemical sensors for the determination and online monitoring of emerging contaminants in degradation processes
• Grantee: Anderson Martin dos Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/04053-0 - Synthesis of new heterogeneous iron-based nanocatalysts (FeSe2 and Fe3O4) for application in the degradation of psychiatric drugs via photo-electro-Fenton process
• Grantee: Fausto Eduardo Bimbi Júnior
• Support Opportunities: Scholarships in Brazil - Doctorate