10.1021/acsomega.6b00477.s001 Seung Hoon Baek Seung Hoon Baek Seung Woo Lee Seung Woo Lee Eun Ju Kim Eun Ju Kim Dong-Hyuk Shin Dong-Hyuk Shin Seog-Won Lee Seog-Won Lee Tae Jung Park Tae Jung Park Portable Agrichemical Detection System for Enhancing the Safety of Agricultural Products Using Aggregation of Gold Nanoparticles American Chemical Society 2017 Portable Agrichemical Detection System OP detection AuNP agrichemical triazole chemicals nm Gold Nanoparticles Organophosphorus device 2017-03-31 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Portable_Agrichemical_Detection_System_for_Enhancing_the_Safety_of_Agricultural_Products_Using_Aggregation_of_Gold_Nanoparticles/4758562 Organophosphorus (OP) and triazole chemicals have been commonly used as insecticides and fungicides to protect agricultural foods from harmful insects and fungi. However, these agrichemicals sometimes remain after distribution and can cause serious health and environmental issues. Therefore, it is essential to detect OPs and triazole chemicals in agricultural products. Nowadays, many detection techniques for OPs and triazole chemicals are expensive and time-consuming and require highly trained technicians. Thus, particularly rapid, simple, and sensitive detection methods are in demand for on-site screening of agrichemicals. Gold nanoparticles (AuNPs) have been utilized for applications in analytical assays and real-time monitoring in the biosensor field because of their biocompatibility and outstanding size-dependent optical properties. In this study, we used AuNPs as a detection probe, which have a size of 17 nm in diameter, a red color, and the absorbance peak at 520 nm. When imidazole was added to AuNPs mixed with the agrichemicals, the AuNPs aggregated and their colors changed to purple, causing the appearance of a new peak at 660–670 nm, which could be measured within approximately 20 s. Moreover, we developed a novel device for multiple agrichemical detections using an AuNP-aggregation-based spectrometric detection system. This portable device is light, simple, fast, and highly sensitive as well as selective. With this system, agrichemical residues can be easily detected on the spot at a low cost and in a short reaction time.