Ambient light sensor based colorimetric dipstick reader for rapid monitoring organophosphate pesticides on a smart phone.

Organophosphate pesticides (OPs) are widely used around the world to control pests in agricultural, residential, and commercial settings. Ingestion of high-dose OPs could lead to acute toxicity, and persistent influence on health could result from acute poisoning or long-term exposure to low dose OPs. An easy to operate, low cost and home available OPs testing platform is urgently needed. Ambient light sensor (ALS) based smart phone colorimetric reader has the advantages of easy to operate, low cost, high accuracy and versatility. In this work, a novel ALS based smart phone colorimetric dipsticks (CDs) reader was reported for rapid monitoring OPs. In this method, acetylcholinesterase (ACHE) CDs was used to test OPs and results were analyzed using an ALS based reader according to the absorbance of ACHE CDs. The results obtained using the ALS based CDs reader were comparable to those obtained using gas chromatography-mass spectrometry (GC-MS) and Ellman assay. The ALS based CDs reader has the advantages of portable, low cost, and high accuracy, and therefore could act an effective platform for OPs monitoring.