摘要
阴离子树脂Bio-RadAG1-X8对黑色页岩中的Mo有很好的分离纯化效果。该方法可以有效去除Mo同位素分析过程中可能存在的同质异位素干扰(如Zr、Sr等),对其他金属元素的去除效果也比较理想。大部分基体元素如Fe、Ca、Na、Mn、Mg、Sr、Al、Cu、K等可以使用1mol/LHF+0.5mol/LHCl洗脱,随后使用4mol/LHCl洗脱Ti和Zr,最后使用3mol/LHNO3洗脱Mo。在用单元素标准溶液过柱的过程中发现,样品中的Mo主要在前5mL3mol/LHNO3的淋洗液中洗脱,先淋洗出的溶液富集Mo的重同位素,后淋洗出的溶液富集Mo的轻同位素。当上柱的样品量较大时(Mo≥50μg),"柱基体效应"可以忽略不计,该化学纯化法适用于样品-标样交叉法和双稀释剂法;当样品量较小时(Mo<50μg),该化学分离方法只适用于双稀释剂法。
The anion exchange resin Bio-Rad AG1-X8 can be used to separate Mo from matrix elements in black shale and other geological samples.Most matrix elements,such as Fe,Ca,Na,Mn,Mg,Sr,Al,Cu and K,were eluted firstly by 1 mol/L HF＋0.5 mol/L HCl;then Ti and Zr were eluted by 4 mol/L HCl;and Mo was eluted lastly by 3 mol/L HNO3.Sr,which leads Mo isotope fractionation when Mo isotopic composition is analyzed by MC-ICP-MS,can be separated completely from Mo.During the eluting,most Mo was eluted within the first 5 mL HNO3;the heavier Mo isotopes were collected first,then the lighter ones,so the eluant must be collected completely to avoid Mo isotope fractionation.When the amount of Mo in sample is large enough（≥50 μg）,＂column matrix effects＂ can be neglected and the Mo isotopic composition is unchanged after ion exchange separation,so the separation method is suitable for both sample-standard bracketing and double spiking techniques to calibrate the instrumental mass bias;nevertheless,due to ＂column matrix effects＂,this method is suitable for double spiking only when the amount of Mo is small（〈50 μg）.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2011年第4期748-754,共7页
Acta Petrologica et Mineralogica
基金
国土资源部公益性行业科研专项经费(201011027-1F)
国家高技术发展计划(863计划)资助项目(2007AA06Z125)
国家自然科学基金创新群体资助项目(40921001)
关键词
钼同位素
化学纯化
样品-标样交叉法
双稀释剂法
Mo isotope
ion-exchange separation
sample-standard bracketing
double spiking
