基于荧光机制的光纤式农药残留测量系统

根据有机物农药的荧光发光机制,利用光纤传感技术、光栅分光技术和多通道图像传感器技术研制了一种农药残留荧光光谱测量系统。系统以脉冲氙灯为光源,以Y型球面光纤探头传输和探测荧光,以小型平场光谱仪实现荧光分光,以高速数据采集模块实现荧光信号的采集转换。该系统一次曝光即可获得农药的荧光光谱。利用该系统实现了对西维因等农药的荧光光谱特性的实验,结果表明:以319 nm紫外光激发农药溶液时,荧光光谱位于可见光340~750 nm之间,系统的最小检测质量浓度可达0.003 mg/L,当农药质量浓度在0~0.1 mg/L范围之间时系统具有较好的线性关系。利用该仪器对白菜中痕量农药浓度进行了测试,其回收率接近100%。

Fiber-Optic Measurement System for Pesticides Residua Based on Fluorescence Mechanism

A measurement system is introduced using the technologies of fiber-optic sensing, dispersion of grating and multi-channel image sensing based on fluorescence mechanism of pesticides. The system adopts a pulsed xenon lamp as an excitation light source, chooses optical fibers to transmit and detect fluorescence, implements dispersion of fluorescence with a small-sized flat field grating spectrometer and conducts data gathering and conversion with a high speed signal processing module. A full fluorescence spectrum of pesticides within a single exposure can be gotten. Moreover, it is used to conduct the measurement of fluorescence characteristics of carbaryl and carbofuran. The results show that the pesticides can emit fluorescence of 340～750 nm as excited by ultraviolet (UV) light of 319 nm,and the system has a good linear relationship in the range of 0.003～0.1 mg/L and the minimum detecting limit is 0.003 mg/L. At the same time, the instrument is also be applied to detect concentration of the trace pesticides in Chinese cabbages,the recovery may be closed to 100%.