the feasibility of measuring pesticides by fluorescence method has been analyzed on the foundational principle that molecules of organic substance can emit fluorescence when excitated by rays. A fiber-optic fluorescent measuring system

which can be used for detecting the organic pesticides in soil

has been put forward based on the techniques of fiber-optic sensing and fluorescence analysis. In the system

a pulsed xenon lamp is used as an excitation lamp source

a self-made cone-shape fiber-optic probe for detecting the fluorescence

a small-sized flat field grating spectrometer for dispersing fluorescence

a high-speed data-collecting module for collecting and converting the fluorescent signals. The fluorescence’s spectrum of the pesticide can be obtained with only one exposure of the system. In this way

the fluorescence experiments on carbaryl of different concentration in soil are done and the working curve and the minimum detecting limit of the system is examined. The results show the system can get high-resolution fluorescence spectra

and has a linear relationship between the fluorescence intensity and the concentration in the range of 0.005~0.1mg/kg. and the minimum detecting density(LOD) is 0.005mg/kg

the relative standard deviation(RSD) is ≤3 %. Consequently

the system can surely meet the need of detecting pesticides in soil.