茶叶辐照的热释光分析研究

Thermo-luminescence for Qualifying Irradiated Tea

不采用二次辐照,将TL分析法应用于辐照茶叶的定性鉴定。分离并收集茶叶中黏附的硅酸盐,采用热释光剂量仪测量获得硅酸盐的热释光发光曲线,比较未辐照与辐照不同剂量茶叶的热释光发光曲线的积分强度、峰值和峰值温度等特征参数。未辐照茶叶的热释光发光曲线的积分强度小于50、峰值小于0.4、峰值温度大于260℃;反之,辐照茶叶的热释光发光曲线的积分强度大于50000、峰值大于600、峰值温度位于160～190℃。TL分析法能判别出茶叶的辐照与否,尤其对不能满足参比剂量辐照条件的样品很有帮助。

Objective：To explore the qualitative identification of irradiated tea through thermo-luminescence （TL） analysis. Methods：Silicate minerals from tea were isolated,collected and measured with TL dosimeter. A TL glow curve was established. The comparisons of integrated intensity,peak value and peak temperature of TL glow curve between unirradiated tea and irradiated tea samples at different irradiation dosages were made. Results：The integrated intensity of TL glow curves of unirradiated tea samples was less than 50; the peak value did not exceed 0.4,and the peak temperature was more than 260 ℃. However,the integrated intensity of TL glow curves of irradiated tea samples was larger than 50000; the peak value was higher than 600,and the peak temperature was in the range of 160 to 190 ℃. Conclusion：TL analysis method can discriminate irradiated tea and unirradiated tea well. This method is very useful,especially for samples that can not be irradiated at the reference dosage.