Flexible non-enzymatic electrochemical sensors with graphene nanoconfined ZrO2 composites for monitoring and discriminating multiple nitroaromatic organophosphorus pesticides

Here, an ultrasensitive zirconium oxide/reduced graphene oxide (ZrO 2 /rGO) non-enzymatic electrochemical sensor was developed for discriminating multicomponent (MP: methyl parathion; FEN: fenitrothion; PAR: paraoxon) aromatic OPs. Specifically, ZrO 2 nanosheets of uniform size (∼50 nm) were fabricated using hierarchically structured GO paper as a sacrificial template, and the prepared ZrO 2 nanofilms exhibited layered structure and high specific surface area due to the nano-confinement of the GO sheets. According to the Lewis acid-base theory and the intrinsic electrochemical properties of OPs, the as-prepared ZrO 2 nanosheets exhibited efficient enrichment and sensing of OPs. Meanwhile, coupled with a linear discriminant analysis (LDA) method, it could accurately discriminate complex mixtures of pesticides. Subsequently, a portable ZrO 2 /rGO sensing platform with a high pore structure was constructed by vacuum filtration to further enhance the detection sensitivity for in-situ determination of OPs. Employing cabbage as a real sample to validate the sensing platform, the two typical factor score plots explained 100 % of the total variance, confirming the reliability of the paper-based sensors in distinguishing 13 different proportions of mixed samples. These efforts provide promising strategies for the development of efficient, portable and sensitive electrochemical sensors for OPs.