Laser-pyrolyzed electrochemical paper-based analytical sensor for sulphite analysis
Alisson Bezerra, Martins Alnilan Lobato, Nikola Tasić, Fernando J. Perez-Sanz, Pedro Vidinha, Thiago R. L. C. Paixão, Luís Moreira Gonçalves
A CO2 laser can be used to pyrolyze the surface of common paperboard to produce a conductive carbon material for subsequent use as an electrode for general electrochemical measurements. In this work, a laser-pyrolyzed electrochemical paper-based analytical device (LP-ePAD) of this type was combined with a gas-diffusion microextraction (GDME) unit for the square-wave voltammetric analysis of sulphites in commercial beverages. The fabricated LP-ePAD had a resistivity at room temperature of 11 ± 4 Ω per square electrical sheet (measured with a four-point probe system). The developed methodology showed a limit of detection of 1 mg L−1 for sulphite analysis, with good repeatability and reproducibility (coefficient of variation below 7%), as well having as the desirable qualities of portability and low price.