Portable wireless intelligent sensing of ultra-trace phytoregulator α-naphthalene acetic acid using self-assembled phosphorene/Ti3C2-MXene nanohybrid with high ambient stability on laser induced porous graphene as nanozyme flexible electrode.

Abstract The harm of pesticide residues to human health via environmental pollution in agriculture has recently become a significant livelihood issue. Herein, a new strategy for smart ultra-trace analysis of phytoregulator α-naphthalene acetic acid (NAA) residues in farmland environments and agro-products via machine learning (ML) using a nanozyme flexible electrode fabricated by two-dimensional phosphorene (BP) nanohybrid with graphene-like titanium carbide MXene (Ti3C2-MXene) on the flexible substrate surface of laser-induced porous graphene (LIPG) is proposed. Highly ambient-stable BP nanohybrid with Ti3C2-MXene is prepared by ultrasonic-assisted liquid-phase exfoliation in organic solvent containing grinding black phosphorus, cuprous chloride and, Ti3C2-MXene that is obtained by selectively etching Al layers of Ti3AlC2. Nanozyme flexible electrode is fabricated by drop-coating Ti3C2-MXene/BP that is formed through electrostatic self-assembly between positively charged BP and negatively charged Ti3C2-MXene onto LIPG that is obtained by direct laser writing on commercial polyimide and patterned via a computer-aided design system as a flexible substrate. The ML model via artificial neural network algorithm for smart output of NAA is discussed. NAA is electrochemically detected in a wide linear range of 0.02–40 μM with a low limit of detection (LOD) of 1.6 nM using a portable mini-workstation. Large and rough surfaces, excellent electrochemical response, and satisfactory practicability demonstrated the feasibility and detectability of the proposed method. This will provide a portable wireless intelligent nanozyme flexible sensing platform for cost-effective, simple, fast and, ultra-trace detection of hazardous substances in the safety of environments, products, and food in agriculture.