水中54Mn的放射化学测定方法
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摘要: 基于水中的放射性Mn和加入Mn(Fe)载体以Mn(OH)2(Fe)共沉淀浓集,采用MnO2沉淀纯化、盐酸-丙酮混合液中的阳离子交换色层法分离纯化Mn2+以及MnNH4PO4·H2O沉淀制源,最后用高纯锗-低本底γ谱仪测定54Mnγ放射性活度。当10l水中加入2.03Bq54Mn和9.63mgMn2+载体时,全程化学回收率和放化回收率分别为(76.4±6.1)%和(77.1±5.9)%。对60Co、63Ni、59Fe、65Zn、51Cr、137Cs、90Sr、95Zr、106Ru-106Rh、144Ce-144Pr的去污系数均大于1×104。本法对水中54Mn的探测下限为4×10-3Bq·l-1。Abstract: RADIOCHEMICALDETERMINATIONOF54MnINWATERLiYunlong(ChinaInstituteofAtomicEnergy,Beijing102413)ABSTRACTAradiochemicaldeterminationprocedurehasbeenestablishedformeasuringtheradioac-tivityof54Mninwater.Theprocedureisbasedonthefolowingprocesses:(1)coprecipitationofhydroxideofmanganeseandirontoconcentrateradioactivemanganeseinthesample;(2)precipitationofMnO2topurifymanganesefromotherimpurities;(3)separationbycationexchangechromatographyinhydrochloricacid-acetonemixturetoseparateandpurifyMn2+fromimpuritynuclidesinthesample;and(4)preparationofmanganeseammoniumphos-phateprecipitate.Finaly,thegammaradioactivityof54MnintheprecipitateiscountedbyalowbackgroundgammaspectrometerwithaHPGedetector.When2.03Bqof54Mnand9.63mgofMn2+areaddedinto10litersofwater,thechemicalandradiochemicalrecoveryoftheprocedureare(76.4±6.1)%and(77.1±5.9)%,respectively.Thedecontaminationfactorsfornuclides60Co,63Ni,59Fe,65Zn,51Cr,137Cs,90Sr,95Zr,106Ru-106Rh,and144Ce-144Praregreaterthan1×104.Theminimumdeterminableconcentrationfor54Mninwateris4×10-3Bq·l-1。Keywordsradiochemicalanalysis54Mnwaterhydrochloricacid-acetonemixturecationexchangechromatography