The use of pesticides will have an impact on food, organisms, and environment. Specifically, pesticide residues in food will damage human health. Because of its high permeability, low energy, high spectral resolution, and fingerprint characteristics, terahertz frequency-domain spectroscopy has been introduced into the determination of pesticides (imidacloprid, acetamiprid, and triadimefon) residues in food samples (glutinous rice flour, wheat flour, and corn flour) in our present study. These three pesticides exhibit their own absorption peaks in the region of 0.4–1.7 THz. For understanding the origins of these peaks, the experimental data are interpreted by using density functional theory calculations at the level of B3LYP/6-31G (d). It is found that these absorption peaks come from the intramolecular and intermolecular interactions. The absorption peaks of pesticides are still detectable in a mixture of pesticides and food samples when they reach a certain concentration. The results from chemometrics analysis show that quantitative detection of pesticides in food samples is feasible. The partial least squares regression models have high correlation coefficient (>0.99), low root-mean-square error of calibration (<1.5%), low root-mean-square error of cross-validation (<2.4%), and low root-mean-square error of prediction (<2.3%), indicating good quality of prediction for pesticides concentration. Our results prove that the terahertz frequency-domain spectrum combined with chemometrics can be used for the detection of pesticides in food samples.

中文翻译：

---

使用THz-FDS和化学计量学检测食品样品中农药的可行方法

农药的使用将对食品，生物和环境产生影响。具体而言，食物中的农药残留会损害人体健康。由于太赫兹的高渗透性，低能量，高光谱分辨率和指纹特征，太赫兹频域光谱法已被用于食品样品（糯米粉，小麦粉，和玉米粉）。这三种农药在0.4–1.7 THz的范围内表现出自己的吸收峰。为了理解这些峰的起源，使用B3LYP / 6-31G（d）水平的密度泛函理论计算来解释实验数据。发现这些吸收峰来自分子内和分子间的相互作用。当农药和食品样品达到一定浓度时，仍然可以检测到农药的吸收峰。化学计量学分析的结果表明，定量检测食品样品中的农药是可行的。偏最小二乘回归模型具有较高的相关系数（> 0.99），较低的校准均方根误差（<1.5％），较低的交叉验证均方根误差（<2.4％）和较低的根-预测的均方误差（<2.3％），表明农药浓度的预测质量良好。我们的结果证明，太赫兹频域谱与化学计量学相结合可用于食品样品中农药的检测。