Sulfamethoxazole Detection in Milk Using a Carbon-Based Printed Electrode: Enhanced Selectivity and Response Stability by Pulse-Amperometry

Author(s)

Boane, Anastacio A. ; Araujo, Diele A. G. ; Munoz, Rodrigo A. A. ; Paixao, Thiago R. L. C. ; Richter, Eduardo M.

• Document type: Journal article
• Source: Journal of the Electrochemical Society; v. 172, n. 2, p. 8-pg., 2025-02-01.

Abstract

A simple, low-cost, and lab-made carbon-based electrode was developed for the fast and selective determination of sulfamethoxazole (SMX) in milk samples, requiring only minimal sample preparation (dilution in supporting electrolyte). A custom-made conductive ink (composed of glass varnish, graphite, acetone) was applied to a plastic surface to fabricate a flow-through amperometric sensor integrated into a portable Batch Injection Analysis (BIA) system. This method enhanced selectivity and reduced electrode contamination. The optimized pulsed amperometric waveform conditions included two detection pulses (+1.0 V and +1.3 V) and two cleaning pulses (+1.5 V and -1.5 V), resulting in a linear response from 1.0 to 20.0 mu mol L-1, with a detection limit of 0.31 mu mol L-1. The stability and reproducibility of the method were confirmed, exhibiting low relative standard deviations (RSD <= 8.3%). The system exhibited excellent recovery for spiked milk samples at concentrations of 5.0 mu mol L-1 (68 +/- 7%), 10.0 mu mol L-1 (103 +/- 7%), and 20.0 mu mol L-1 (115 +/- 7%), demonstrating high accuracy and minimal matrix interference. This approach offers a rapid, accurate, and reliable method for the analysis of complex samples, particularly for onsite detection of SMX in milk. Low-cost and and lab-made disposable carbon-based sensors for complex sample analysis.Portable amperometric method for selective determination of sulfamethoxazole in milk samples.Simple and rapid sample preparation step (dilution in supporting electrolyte). (AU)

• FAPESP's process: 22/01810-5 - 3D-PRINTING AND TEXTILE THREADS-BASED MICROFLUIDIC PLATFORMS FOR ELECTROANALYSIS OF CLINICAL, ENVIRONMENTAL AND BIOLOGICAL SAMPLES
• Grantee: Diele Aparecida Gouveia Araújo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 23/00246-1 - Miniaturized large-scale devices for in-situ analysis: fabrication, characterization and applications
• Grantee: Mauro Bertotti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/08782-1 - Miniaturized and integrated chemical sensors: new fabrication platforms for biological, clinical and environmental applications
• Grantee: Mauro Bertotti
• Support Opportunities: Research Projects - Thematic Grants