title: Feasibility of using terahertz spectroscopy to detect seven different pesticides in wheat flour.
abstract: This study investigated the feasibility of detecting pesticides using terahertz (THz) spectroscopy in high-density polyethylene and/or wheat flour mixtures. The absorption spectra of seven pesticides (dicofol, chlorpyrifos, chlorpyrifos-methyl, daminozide, imidacloprid, diethyldithiocarbamate, and dimethyldithiocarbamate) were measured in the frequency range 0.1 to 3 THz at room temperature. Five of the seven pesticides exhibited specific absorption peaks in the low-energy THz range. The two remaining pesticides had no specific absorption peaks in this frequency range, but they exhibited different frequency-dependent refractive indices. The absorption coefficients of imidacloprid increased with its increasing weight ratio in high-density polyethylene, and the fitted power absorptions and refractive indices using a Maxwell-Garnett effective medium model were comparable to the measured data. Imidacloprid was also identified from its characteristic absorption peaks in wheat flour mixtures, and a linear relationship between the absorption coefficient and the weight ratio was observed. Our results show the potential of detection of selected pesticides in foods, such as wheat flour, using THz spectroscopy.
authors.affiliation: Department of Chemistry and School of Food Science and Technology, Chung-Ang University, Ansung, Gyounggi 456-756, Republic of Korea.
authors.forename: Inhee
authors.initials: I
authors.lastname: Maeng
authors.affiliation: Department of Chemistry and School of Food Science and Technology, Chung-Ang University, Ansung, Gyounggi 456-756, Republic of Korea.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Chemistry and School of Food Science and Technology, Chung-Ang University, Ansung, Gyounggi 456-756, Republic of Korea.
authors.forename: Hwa Yeon
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Food Safety Research Center, Korea Food Research Institute, Sungnam 463-746, Republic of Korea.
authors.forename: Gyeong-Sik
authors.initials: GS
authors.lastname: Ok
authors.affiliation: Food Safety Research Center, Korea Food Research Institute, Sungnam 463-746, Republic of Korea.
authors.forename: Sung-Wook
authors.initials: SW
authors.lastname: Choi
authors.affiliation: Department of Chemistry and School of Food Science and Technology, Chung-Ang University, Ansung, Gyounggi 456-756, Republic of Korea. hschun@cau.ac.kr.
authors.forename: Hyang Sook
authors.initials: HS
authors.lastname: Chun
mesh_terms: D002219:Carbamates / Q000032:analysis; D004390:Chlorpyrifos / Q000031:analogs & derivatives / Q000032:analysis; D004010:Dicofol / Q000032:analysis; D004125:Dimethyldithiocarbamate / Q000032:analysis; D004050:Ditiocarb / Q000032:analysis; D005240:Feasibility Studies; D005433:Flour / Q000032:analysis*; D007093:Imidazoles / Q000032:analysis; D016018:Least-Squares Analysis; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D020959:Polyethylene; D012639:Seeds / Q000737:chemistry; D013386:Succinates / Q000032:analysis; D055068:Terahertz Spectroscopy; D014908:Triticum / Q000737:chemistry*
chemical_list: D002219:Carbamates; D004125:Dimethyldithiocarbamate; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010575:Pesticides; D013386:Succinates; C082359:imidacloprid; D020959:Polyethylene; D004050:Ditiocarb; C014499:daminozide; D004390:Chlorpyrifos; C007031:chlorpyrifos-methyl; D004010:Dicofol