Development of an o-COSAN Ion-Pair Complex-Modified PVC Membrane for Microconductometric Glyphosate Detection

Glyphosate is among the most widely used herbicides worldwide, and its extensive application has led to increasing concerns regarding environmental contamination and potential risks to human health. The persistence of this compound in soil and aquatic environments has created an urgent demand for analytical methods that are rapid, reliable, and economically feasible. In the present study, a microconductometric sensing platform was developed for glyphosate determination using a PVC liquid membrane incorporating an [o-COSAN]⁻/glyphosate ion-pair complex deposited onto interdigitated electrodes. The proposed sensor provided a linear analytical response over the concentration range of 1.0 × 10⁻⁵ to 2.5 × 10⁻³ M, with a detection limit of 4 μM. The device also exhibited excellent analytical performance, with reproducibility and repeatability values of 3% and 8% (RSD), respectively. Furthermore, the sensor maintained stable performance for more than three months and showed a high degree of selectivity toward glyphosate when evaluated against potential interfering compounds, including AMPA and carbofuran. These results demonstrate the potential of the proposed sensing platform as a simple, sensitive, and cost-effective tool for glyphosate monitoring in environmental samples.