基于太赫兹时域光谱技术的农药残留检测方法

太赫兹时域光谱(THz-TDS)技术是近年来涌现出来的崭新的光谱测量新技术.本研究提出了一种基于THz-TDS技术农药残留检测方法,并以灭多威和乙氧氟草醚两种农药作为实验介质证明此方法的可行性.应用太赫兹时域光谱系统测得了这两种农药的时域光谱信号,利用基于菲涅尔公式的数据处理模型得到了它们在THz波段的折射率谱和吸收系数谱.从实验结果可以看出两种农药在0.2~2.0THz范围内存在明显的特征吸收峰,且差别很大.经分析认为这些吸收峰是由分子的集体振动模式以及分子间相互作用引起,它们是农药分子的指纹吸收光谱,可以应用于分子识别中.本研究证明了THz-TDS技术应用于农药残留检测的可行性,表明其在农药残留检测中具有潜在的应用价值.

METHOD FOR DETECTION OF PESTICIDE RESIDUE BASED ON TERAHERTZ TIME DOMAIN SPECTROSCOPY

Terahertz time-domain spectroscopy(THz-TDS) technique is a newly developed promising spectroscopy technique based on ultrafast laser technology.A method for pesticide detection based on THz-TDS was reported.Two pesticides,methomyl and oxyfluorfen,were investigated to prove its feasibility.THz-TDS was used to measure their terahertz time domain signals.And their refractive index and absorption coefficient between 0.2THz and 2.0THz were calculated by using models based on Fresnel equations.The experimental results indicate that a series of distinct sharp characteristic absorption peaks can be observed clearly and absorption spectra of these two pesticides are completely different.Our analysis show that these absorption peaks may originate from the collective vibration modes and intermolecular vibration,and these fingerprint spectra can be used to identify the samples.Our research indicates that it is feasible to detect pesticide residue by using terahertz technology,and THz-TDS technique is a promising technique for pesticide residue analysis.