A novel test strip for organophosphorus detection

• We present a novel structure test strip for fixing highly sensitive probe used for organophosphorus assessment.
• Test strip holds the advantages such as easy observation, rapid analysis speed, easy operation, low cost, easy transportation and storage.
• Results of the strips can be checked by naked eye.

Herein we present a novel sandwich structure test strip for organophosphorus (OP) assessment, which is applicable and portable for field application. The middle layer of the strip is made of rhodamine B-covered gold nanoparticles (RB–Au NPs) entrapped in agarose and its coated layer is made of hydrogel (Poly ethylene glycol diacrylate) used as protectors for the center agarose layer. The OP assessment is based on the measurement of the concentration changing of thiocholine (generated from acetylthiocholine catalyzed by acetylcholinesterase in tested solution) when OP exist. The strip was further validated by various pesticide samples. Its detection limit was demonstrated to meet the maximum residue limits reported in the European Union pesticides database. Our strip also showed its good sensitivity and high reliability on testing river water samples, which suggested its great potential in environmental analysis.