Highly selective turn-on chemodosimetric sensing of proline for environmental and hydroponic monitoring

Proline is an important biomarker in biological regulation and plant stress adaptation, increasing the demand for highly specific analytical detection methods. Herein, we report the use of DMAC as a chemodosimetric probe that exclusively identifies proline in the presence of 19 competing amino acids. The sensing mechanism relies on an irreversible chemical reaction between proline and DMAC, producing a distinct optical response with negligible background interference. This exhibits a highly sensitive limit of detection of 15.8 nM (1.82 ppb), signifying its importance in trace-level quantification. We thoroughly validated the underlying reaction mechanism using a combination of experimental and theoretical techniques. To demonstrate real-world applicability, the DMAC probe was integrated into a microfluidic device, resulting in a portable device designed for rapid, on-site analysis. Finally, the sensor's practical utility was demonstrated by successfully monitoring proline dynamics during plant growth.