title: Terahertz sensing of chlorpyrifos-methyl using metamaterials.
abstract: By squeezing electromagnetic energy into small volumes near a metal-dielectric interface, plasmonics provide many routes to enhance and manipulate light-matter interactions, which presents new strategies for signal enhancing technologies. As an extension of the ideas of plasmonics to the terahertz (THz) range, metamaterials have shown great potential in sensing applications. In this study, terahertz time-domain spectroscopy (THz-TDS) combined with metamaterials was used to detect chlorpyrifos-methyl (CM), which is one type of the broad-spectrum organophosphorus pesticides. The results demonstrate that sensitivity is greatly improved using THz metamaterials, with the limit of detection (LOD) of CM reaching 0.204mgL-1, which is lower than the World Health Organization's provisional guideline limit for CM in vegetables (1mgL-1). The results indicated that THz spectroscopy combined with metamaterials could be a valuable method for highly sensitive THz applications, presenting a new strategy for food quality and safety control in the future.
authors.affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: xuwonder@zju.edu.cn.
authors.forename: Wendao
authors.initials: W
authors.lastname: Xu
authors.affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: ljxie@zju.edu.cn.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Xie
authors.affiliation: State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: zhujianfei@zju.edu.cn.
authors.forename: Jianfei
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: ww_hust@qq.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: zzye@zju.edu.cn.
authors.forename: Zunzhong
authors.initials: Z
authors.lastname: Ye
authors.affiliation: State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: yingyb@zju.edu.cn.
authors.forename: Yungui
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC. Electronic address: chaoyin01@gmail.com.
authors.forename: Chao-Yin
authors.initials: CY
authors.lastname: Tsai
authors.affiliation: Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan, ROC. Electronic address: schen@ntu.edu.tw.
authors.forename: Suming
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China. Electronic address: yingyb@zju.edu.cn.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Ying
mesh_terms: D004390:Chlorpyrifos / Q000031:analogs & derivatives* / Q000032:analysis; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis; D057230:Limit of Detection; D009943:Organophosphorus Compounds / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D055068:Terahertz Spectroscopy; D014675:Vegetables / Q000737:chemistry
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D004390:Chlorpyrifos; C007031:chlorpyrifos-methyl
keywords: Chlorpyrifos-methyl; Chlorpyrifos-methyl (PubChem CID: 21803); Frequency shift; Metamaterials; Signal-enhancing; Terahertz