A novel colorimetric sensor strip for the detection of glyphosate in water

This study presents the development of a novel first generation nanofiber based colorimetric sensor strip for the determination of glyphosate in water. The proposed method was validated with an optical color change of the poly (vinyl) alcohol (cd-PVA (copper doped poly (vinyl) alcohol)) nanofiber sensor strips from blue to yellow upon the injection of the dithiocarbamic acid sample. The sensor strip demonstrated advantageous characteristics including a low sample volume (30 mu l), a rapid response time (similar to 1-3 s), good color spot stability (4 h) and a low cross-reactivity to glyphosate structural analogs, aminomethylphosphonic acid (AMPA) and glycine. The cd-PVA sensor strips were characterized by a practical limit of detection of 0.1 mu g/ml and the sensor strip system was stable for up to 20 days at 23 degrees C (dark conditions). Application of the sensor strip to an environmental water sample (no pre-treatment) indicated very good recovery of 100.9 +/- 8.7% at the mid-range (200 mu g/ml) concentration of glyphosate, however interfering effects were observed at a lower-range (60 mu g/ml) concentration with a recovery of 128.2 +/- 3.1% being observed. Interference studies confirmed the susceptibility of this system to compounds and ions commonly found in environmental waters; therefore pre-treatment of water samples would be required. This system shows great potential for on-site application for high-throughput screening for glyphosate in water. (C) 2014 Elsevier B.V. All rights reserved.