基于液体闪烁计数法测定环境中^(33)P和^(32)P分析方法研究

Analysis of ^(33)P and ^(32)P in the environment by liquid scintillation counting

本研究利用Quantulus GCT 6220超低本底液闪谱仪同时测定环境中的^(33)P和^(32)P,确定了^(33)P和^(32)P的能量区间,并优化了测量条件。结果表明:当闪烁液和样品溶液的体积比大于2、混合溶液体积大于12 mL、避光时间大于6 h、溶液pH为6~7时,计数效率较高。实验过程中选定高能β核素^(32)P能量区间为150~1710 KeV,低能β核素^(33)P (以^(14)C替代)能量区间为0~150 KeV,可以消除同时测量^(33)P和^(32)P的干扰,^(33)P和^(32)P测量效率分别为(54.8±8.7)%和(64.6±3.7)%。基于该方法,计算得到^(33)P和^(32)P在不同环境样品中的探测下限LLD,并将所得结论应用于环境样品的测量。

An ultra-low level liquid scintillation spectrometer(Quantulus GCT 6220)was applied for the simultaneous determination of ^(33)P and ^(32)P in environmental samples.The energy ranges for ^(33)P and ^(32)P and the experimental conditions were optimized.The results showed that counting efficiency was high when volume ratio of cocktail to sample solution was greater than 2,volume of mixed solution was greater than 12 mL,dark time was greater than 6 h,and pH was 6~7.The counting range of ^(32)P was selected to be 150~1710 keV and that of ^(33)P(replaced by ^(14)C)to be 0~150 keV,which could eliminate the interference between the simultaneous measurement of ^(33)P and ^(32)P,with efficiencies of 54.8%±8.7%for ^(33)P and 64.7%±3.7%for _(32)P.Based on this method,the lower limits detections were obtained,and environmental samples were measured.