Artificial intelligence-processed colorimetric sensor based on hierarchically porous iron nanozyme for visualized, rapid, and highly-sensitive detection of carbosulfan with an outstanding detection range.

A hierarchically porous iron-based nanozyme (pFezyme) exhibiting excellent oxidase (OXD)-like activity was successfully synthesized. Carbosulfan decomposes to release sulfide groups (-SH), which significantly diminish the OXD-like activity of nanozyme. Consequently, pFezyme was employed as a colorimetric sensor, enabling the visual, rapid, and sensitive detection of carbosulfan. The pFezyme colorimetric sensor demonstrated a broad detection range (0.7 to 3 × 104 nM), an ultra-low limit of detection (0.48 nM), and a rapid detection time (18 min). Furthermore, a portable platform integrated with artificial intelligence (AI) processing was constructed by combining a smartphone with pFezyme colorimetric sensor. Through AI-based processing on smartphone, the color signal from the sensor was rapidly converted into RGB values, maintaining high sensitivity (LOD = 0.67 nM) across the broad detection range (0.7 to 3 × 104 nM). Importantly, both pFezyme colorimetric sensor and AI-integrated portable platform enabled rapid and sensitive detection of carbosulfan in food samples.