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从24h尿中取样750ml,加入HNO3-H2O3,以温式友化去除有机物。在0.5-1.0mol/lHNO3介质中,用30%TRPO-二甲苯萃取239,240Pu等α核素。在H2O2作用下,Np为Np(Ⅴ),其萃取分配比极低;Am(Ⅲ)等核素被萃取,用5.5mol/lHNO3洗涤去除。以0.01mol/lHNO3洗涤有机相,去除绝大部分被萃HNO3后,加入UltimaGoldF闪烁液,于低本底TRI-CARB2550TR/AB液闪仪上测量α放射性计数率。根据239,240Pu测量窗的计数效率,扣除尿样α本底值后计算出从事钚操作职业人员尿中239,240Pu的放射性活度。取样750ml,方法对α的最低检测限为0.7mBq。经示踪法检验,方法精密度为3%,放化回收率为99%±3%。
From 24h urine sample 750ml, adding HNO3-H2O3, to the Friends of the warm temperature to remove organic matter. In 0.5-1.0mol / lHNO3 medium, extract 239,240Pu and other α-nuclides with 30% TRPO-xylene. Under the action of H2O2, Np is Np (Ⅴ), and the extraction and distribution ratio is very low. The nuclides such as Am (Ⅲ) are extracted and washed with 5.5 mol / l HNO3. The organic phase was washed with 0.01 mol / l HNO3 and most of the extracted HNO3 was removed. Ultima Gold F scintillation was added and the alpha radioactivity count was measured on a low background TRI-CARB2550TR / AB liquid scintillator. Based on the counting efficiency of the 239,240Pu measurement window, the radioactivity of 239,240Pu in the urine of professionals working in plutonium was calculated after deducting the alpha value of urine samples. Sampling 750ml, the method of α minimum detection limit of 0.7mBq. Tracer method test, the method precision of 3%, radiochemical recovery was 99% ± 3%.