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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%.