TY - JOUR
T1 - Detection of Methomyl, a Carbamate Insecticide, in Food Matrices Using Terahertz Time-Domain Spectroscopy
AU - Baek, Seung Hyun
AU - Kang, Ju Hee
AU - Hwang, Yeun Hee
AU - Ok, Kang Min
AU - Kwak, Kyungwon
AU - Chun, Hyang Sook
N1 - Funding Information:
This research was supported by the Public Welfare and Safety Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2010-0020819) and by the Chung-Ang University Research Scholarship Grants in 2014.
Publisher Copyright:
© 2015, Springer Science+Business Media New York.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - The aim of this study was to investigate the feasibility of detecting methomyl, a carbamate insecticide, in food matrices (wheat and rice flours) using terahertz time-domain spectroscopy (THz-TDS). In the frequency range 0.1–3 THz, the characteristic THz absorption peaks of methomyl at room temperature were detected at 1 (33.4 cm−1), 1.64 (54.7 cm−1), and 1.89 (63.0 cm−1) THz. For detailed spectral analysis, the vibrational frequency and intensity of methomyl were calculated using solid-state density functional theory to mimic molecular interactions in the solid state. Qualitatively, the simulated spectrum was in good agreement with the experimental spectrum. Analysis of the individual absorption modes revealed that all of the features in the THz spectrum of methomyl were mainly generated from intermolecular vibrations. The peak appearing at 1 THz (33.4 cm−1) was then selected and tested for its suitability as a fingerprint for detecting methomyl in food matrices. Its absorbance was dose-dependently distinguishable from that of wheat and rice flours. The calibration curve of methomyl had a regression coefficient of >0.974 and a detection limit of <3.74 %. Accuracy and precision expressed as recovery and relative standard deviation in interday repeatability were in the ranges 78.0–96.5 and 2.83–4.98 %, respectively. Our results suggest that THz-TDS can be used for the rapid detection of methomyl in foods, but its sensitivity needs to be improved.
AB - The aim of this study was to investigate the feasibility of detecting methomyl, a carbamate insecticide, in food matrices (wheat and rice flours) using terahertz time-domain spectroscopy (THz-TDS). In the frequency range 0.1–3 THz, the characteristic THz absorption peaks of methomyl at room temperature were detected at 1 (33.4 cm−1), 1.64 (54.7 cm−1), and 1.89 (63.0 cm−1) THz. For detailed spectral analysis, the vibrational frequency and intensity of methomyl were calculated using solid-state density functional theory to mimic molecular interactions in the solid state. Qualitatively, the simulated spectrum was in good agreement with the experimental spectrum. Analysis of the individual absorption modes revealed that all of the features in the THz spectrum of methomyl were mainly generated from intermolecular vibrations. The peak appearing at 1 THz (33.4 cm−1) was then selected and tested for its suitability as a fingerprint for detecting methomyl in food matrices. Its absorbance was dose-dependently distinguishable from that of wheat and rice flours. The calibration curve of methomyl had a regression coefficient of >0.974 and a detection limit of <3.74 %. Accuracy and precision expressed as recovery and relative standard deviation in interday repeatability were in the ranges 78.0–96.5 and 2.83–4.98 %, respectively. Our results suggest that THz-TDS can be used for the rapid detection of methomyl in foods, but its sensitivity needs to be improved.
KW - Detection
KW - Methomyl
KW - Solid-state density functional theory
KW - Terahertz time-domain spectroscopy
KW - Wheat and rice flours
UR - http://www.scopus.com/inward/record.url?scp=84950263877&partnerID=8YFLogxK
U2 - 10.1007/s10762-015-0234-9
DO - 10.1007/s10762-015-0234-9
M3 - Article
AN - SCOPUS:84950263877
SN - 1866-6892
VL - 37
SP - 486
EP - 497
JO - Journal of Infrared, Millimeter, and Terahertz Waves
JF - Journal of Infrared, Millimeter, and Terahertz Waves
IS - 5
ER -