Development of highly selective optode-based sensors supported on Pluronic F-127 nanomicelles and functionalized 2-μm paper for ammonium ion quantification in agricultural irrigation water

Villanueva M.; Vega-Chacón J.; Picasso G. · Microchemical Journal (2026) · DOI: 10.1016/j.microc.2026.117957

Resumen

Monitoring ammonium ions (NH₄+) is essential in agricultural systems to optimize fertilizer application and prevent soil and water contamination. In this study, a dual-platform colorimetric optode system for ammonium detection was developed by integrating ion-exchange optode chemistry with nanostructured Pluronic F-127 micelles and functionalized cellulose paper substrates. This approach enables a direct comparison between micellar and paper-based sensing environments while maintaining identical sensing chemistry based on nonactin and chromoionophores. The sensing mechanism is governed by the activity driven complexation of NH₄+ with nonactin and proton exchange involving the chromoionophore. This process induces a reversible color change that is quantified using RGB color-space analysis. The micellar platform enhances ion diffusion and improves optical stability, whereas the paper-based system enables rapid and portable measurements. The optodes exhibited high sensitivity, with detection limits in the micromolar range, and demonstrated strong selectivity against common interfering ions, including Na+, Li+, K+, Ca2+, and Mg2+. Both platforms were successfully applied to agricultural irrigation water samples, enabling accurate in situ ammonium quantification without the need for complex instrumentation. Overall, this work presents a portable, low-cost, and environmentally friendly optical sensing strategy for real-time NH₄+ monitoring under field conditions, offering a promising tool for sustainable agricultural management.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad Nacional de Ingeniería