摘要
利用多接收电感耦合等离子体质谱仪测定Mg同位素比值时,样品溶液中的基质元素可影响Mg同位素比值的准确测定。根据白云鄂博样品富含REE、Nb、Fe(REE质量分数可达10%、Nb质量分数可达0.1%)等元素的特性,本研究在评估测试溶液中Nd(REE)、Mn元素质量比对Mg同位素比值影响的基础上,建立了适用于富含REE、Nb、Fe等元素的特殊样品中Mg同位素的化学纯化方法。研究表明,当m(Nd)/m(Mg)>0.2、m(Mn)/m(Mg)>0.2时,REE和Mn的存在明显影响Mg同位素测定值的准确性,应予以去除。所建纯化方法首先是利用AG MP-1阴离子交换树脂,以10mol/L HCl+0.001%H2O2溶液为上样介质和淋洗液,接取前2.5mL淋洗液,去除样品中Fe、Mn等杂质元素;然后利用AG50W-X12阳离子交换树脂,以2mol/L HCl为上样介质和淋洗液,去除REE、Nb等杂质元素。所建方法满足多接收器等离子体质谱进行高REE-Nb-Fe-Mn样品中Mg同位素测定的要求。
The measured values of Mg isotope ratios using multi-collector inductively coupled plasma mass spectrometry may be effected by matrix elements to certain extent. Some geological samples such as those from the Baiyan Obo ore deposit may have exceptionally high contents of REE, Nb, Fe and Mn. An investigation of effects of matrix elements on Mg isotope ratio measurement has been carried out. The results show that the measured 826 Mg deviates from true value when the matrix/Mg（mass fraction） is over 0.2. Thus it is necessary to resolve these matrix elements before determining the ~6 Mg value. Firstly, the protocols established for Mg purification are using AG MP - 1 anion exchange resin and 2.5 mL 10 mol/L HC14-0. 001% H2O2 reagents as loading medium and eluant, the first 2. 5 mL eluant contains Mg but no Fe and Mn; and then using AG50W- X12 cation exchange resin and 2 mol/L HC1 as loading medium and eluants, the eluant from 2 -7 mL 2 mol/L contain Mg but no REE,Nb and other matrix elemts.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2013年第1期142-148,共7页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(40973037)
国土资源公益性行业科研专项项目(200911043-14)
