Babassu mesocarp (Orbignya phalerata Mart) nanoparticle-based biosensors for indirect sulfite detection in industrial juices

The present work proposes a new electrochemical sulfite biosensor based on babassu mesocarp nanoparticles (BMNPs) immobilized on the surface of a pyrolytic graphite electrode (PGE). The synthesized nanoparticles had a size of 121.5 nm and a zeta potential of − 28.1 mV and were used as a support for the immobilization of chitosan (CHIT) and polyphenol oxidase (PPO) obtained from sweet potatoes ( Ipomea batatas (L.)). The electrochemical activity of the PGE/BMNPs/CHIT/GA/PPO biosensor was measured using cyclic voltammetry (CV) and square wave voltammetry (SWV), and the biosensor was shown to have a sensitivity of 2.18 μA/μmol L −1 , a detection limit of 0.151 μmol L −1 , and quantitation limit of 0.452 μmol L −1 for sulfite. The principle of analysis for the developed biosensor is based on the inhibitory effect of sulfite on the activity of the PPO enzyme. This biosensor was successfully employed for the analysis of industrial juice, without the need to pre-treat the sample. Graphical abstract .