Integrated all-solid-state sulfite sensors modified with two different ion-to-electron transducers: rapid assessment of sulfite in beverages

Abstract

An integrated all-solid-state screen-printed ion-selective potentiometric sensor for rapid assessment of sulfite ion in beverages, based on analytical transduction, is described. The constructed potentiometric cell incorporates a polymeric membrane sulfite ion-selective electrode based on cobalt(II) phthalocyanine (CoPC) as a recognition material and an Ag/AgCl reference electrode with a polyvinyl butyral reference membrane. Two different solid-contact transducers, namely multi-walled carbon nanotubes (MWCNTs) and polyaniline (PANI) were used for a comparative study. The presented sensors exhibited a rapid Nernst response across the concentration ranges from 2.0 × 10⁻⁶ to 2.3 × 10⁻³ M and from 5.0 × 10⁻⁶ to 2.3 × 10⁻³ M with detection limits equal to 1.1 × 10⁻⁶ M and 1.5 × 10⁻⁶ M for sensors based on MWCNTs and PANI, respectively. The proposed sensors manifested high selectivity and sensitivity, enhanced stability and low cost that provides a wide number of potential applications for food analysis. Good performance characteristics were obtained for the proposed method after applying the validation requirements. Method precision, accuracy, bias, trueness, repeatability, reproducibility, and uncertainty are examined. These analytical capabilities support the rapid and direct determination of sulfite in different beverage samples. The analytical results were verified and compared with the standard iodometric method.