A Fast Separation Method for Isotope Analysis Based on Compressed Nitrogen Gas and Ion-Exchange Chromatography Technique--A Case Study of Sr-Nd Isotope Measurement  

作　　者：Honglin Yuan Xu Liu Zhian Bao Kaiyun Chen Chunlei Zong 

机构地区：[1]State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University [2] Collaborative Innovation Center of Continental Tectonics, Xi'an 710069, China [2]College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China

出　　处：《Journal of Earth Science》2018年第1期223-229,共7页地球科学学刊（英文版）

基　　金：co-supported by the National Natural Science Foundation of China (Nos. 41427804, 41421002, 41373004);Program for Changjiang Scholars and Innovative Research Team in University of China (No. IRT1281);the MOST Research Foundation from the State Key Laboratory of Continental Dynamics

摘　　要：High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and puri- fication, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry （MC-ICPMS） analysis. For Cu isotope separation, our results indicated that at a gas flow rate 〉60 mL/min, the separation chromatographic peaks broadened and the re-covery rate decreased to 〈99.2%. On the other hand, no significant change in the Cu peaks was ob- served at a gas flow rate of 20 mL/min and the recovery rate was determined to be 〉99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a±2 SD error range. The separation time was reduced from the traditional 10 h （without N2） to 4 h （with N2）, indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 （US Geological Survey andesite standard sample） accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N2, the purified liquid comprised Rb/Sr and Sm/Nd ratios of 〈0.000 049 and 〈0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a±2 SD error range and the total separation time was shortened from 2 d to 〈10 h.High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and puri- fication, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry （MC-ICPMS） analysis. For Cu isotope separation, our results indicated that at a gas flow rate 〉60 mL/min, the separation chromatographic peaks broadened and the re-covery rate decreased to 〈99.2%. On the other hand, no significant change in the Cu peaks was ob- served at a gas flow rate of 20 mL/min and the recovery rate was determined to be 〉99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a±2 SD error range. The separation time was reduced from the traditional 10 h （without N2） to 4 h （with N2）, indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 （US Geological Survey andesite standard sample） accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N2, the purified liquid comprised Rb/Sr and Sm/Nd ratios of 〈0.000 049 and 〈0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a±2 SD error range and the total separation time was shortened from 2 d to 〈10 h.

关 键 词：fast isotope purification MC-ICPMS N2 gas flow Cu isotope Sr-Nd isotopes. 

分 类 号：P2[天文地球—测绘科学与技术]