固相萃取片法分析土壤中的99 Tc

摘要

系统研究了阴离子固相萃取片分离水溶液中 TcO-4的性能,包括流速、酸度、体积、土壤基质对吸附的影响。在此基础上,针对土壤中99 Tc含量的分析,建立了以固相萃取片法为主要分离手段、液闪为放射性测量方法的分析流程,并利用模拟99 Tc污染土壤样品对分析流程进行了检验。研究结果表明,土壤中含有的本底放射性核素及常见沾污核素137 Cs、90 Sr-90 Y 和天然铀对分析流程均无明显干扰,全流程99 Tc的化学收率在95%以上。样品质量为10 g、液闪测量能量范围本底计数率为10 min-1、测量时间为10 h时,方法的最小可探测浓度约为0.07 min-1·g-1,即1.1 Bq/kg。%The performance of anion solid phase extraction disk for the separation of TcO-4 ion in aqueous solution was studied systematically.The effects of flow rate,acid-ity,sample volume and soil matrix on adsorption were evaluated with different flow rate load conditions.And on this basis,an analysis procedure using solid phase extraction disk for the routine determination of 99 Tc in soil was presented.The procedure was vali-dated by some simulated contaminated soil samples.The results show that 137 Cs,90 Sr-90 Y,natural uranium and background radionuclides in soil do not interfere with the anal-ysis procedure.The chemical yield of technetium is more than 9 5% for the whole proce-dure.The minimum detectable concentration is 1.1 Bq/kg with sample quantity of 10 g, background counting rate of 10 min-1 and detection time of 10 h.