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 stripfor the determination of glyphosate in water. The proposed method was validated with an optical colorchange of the poly (vinyl) alcohol (cd-PVA (copper doped poly (vinyl) alcohol)) nanofiber sensor stripsfrom blue to yellow upon the injection of the dithiocarbamic acid sample. The sensor strip demonstratedadvantageous characteristics including a low sample volume (30μl), a rapid response time (∼13 s), goodcolor spot stability (4 h) and a low cross-reactivity to glyphosate structural analogs, aminomethylphos-phonic acid (AMPA) and glycine. The cd-PVA sensor strips were characterized by a practical limit ofdetection of 0.1 g/ml and the sensor strip system was stable for up to 20 days at 23°C (dark conditions).Application of the sensor strip to an environmental water sample (no pre-treatment) indicated very goodrecovery of 100.9 ± 8.7% at the mid-range (200μg/ml) concentration of glyphosate, however interferingeffects were observed at a lower-range (60μg/ml) concentration with a recovery of 128.2 ± 3.1% beingobserved. Interference studies confirmed the susceptibility of this system to compounds and ions com-monly 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 glyphosatein water.