Search

BACKGROUND: In the past twenty years, methods for metal isotopes analysis(iron, copper, zinc, magnesium, calcium, lithium, molybdenum, selenium, mercury, chromium, cadmium, alum, barium, titanium, etc.) have been established. The sample pretreatment during metal isotope analysis includes two processes: the digestion of the sample; and the separation and purification of the analyzed elements. In order to ensure the accuracy and precision of metal isotopes data, two general principles of sample treatment must be followed. Elements that may interfere with the isotope analysis of the analyzed elements should not be introduced into the analysis. The analyzed elements should not be lost during the experiment. OBJECTIVES: In order to understand the pretreatment methods for metal isotope analysis. METHODS: Common sample digestion methods and chemical separation(ion exchange separation） were introduced in detail and were discussed in this paper. RESULTS: The common sample digestion method for metal isotope analysis is the acid dissolution method(Teflon bombs and microwave digestion). The separation and purification of the element to be measured mainly uses the ion exchange separation method. The same resin can be used for the chemical separation of different elements, and the same element can also be chemically separated by using different resins. The matrices of different types of samples are quite different, and different processes are required to separate the analyzed elements. The separation requirements of different samples can be met by changing the separation process of the predecessors, including changing the resin or the amount, changing the eluent or the amount, and increasing the separation steps. CONCLUSIONS: Based on the authors’ experience, details should be paid attention to during treatments for metal isotope analysis:（1）HClO4 must be thoroughly removed at high temperature during sample digestion, because its strong oxidization can destroy the effectiveness of resins;（2）when the same volume of resin is put into the column, the thinner the column is, the slower the flow rate of the eluent, and the later elution of the elements to be measured;（3）the smaller the volume of the eluent added each time, the better the separation effect during ion exchange purification. [ABSTRACT FROM AUTHOR]

BACKGROUND: One Rb - Sr certified reference materials (GBW04411) and one Sm - Nd certified reference materials (GBW04419) for geological age, which are potash feldspar and basalt respectively, were produced and certified about 30 years ago. They have only one certified value and their matrices differ from many other geological samples. To better assess the quality of chromatographic separation, measurement procedures and mass spectrometry performance when analyzing Rb - Sr and Sm - Nd, three CRMs which are peridotite, eclogite and granite for Rb - Sr and Sm - Nd analysis were produced, and labelled GBW04139, GBW04140 and GBW04141 respectively. OBJECTIVES: To prepare certified reference materials for analysis of Rb - Sr and Sm - Nd isotopes of different types of rocks. METHODS: Peridotite, eclogite and granite from typical areas in China were used as candidates. Referring to 'Determinations for isotopes of lead, strontium and neodymium in rock samples (GB/T 17672-1999)', 'Determination of Rb Sr isotopic geological age and Sr isotope ratio in rocks and minerals (DZ/T 0184. 4— 1997), Determination of Sm - Nd isotopic geological age and Nd isotope ratio in rocks and minerals (DZ/T 0184.6-1997), Rb, Sr, Sm and Nd were purified by chromatographic separation, and their concentrations were analyzed by ID - TIMS, 87Sr/ 86Sr and 143Nd/ 144Nd ratios were determined by TIMS and MC - ICP-MS, respectively. RESULTS: For homogeneity testing of the three CRMs, fifteen bottles of each were randomly selected (from the 200 bottles prepared) for analysis. F-testing was used to study homogeneity. The result was insignificant (1

Copyright of Acta Geoscientica Sinica is the property of Acta Geoscientica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

143Nd/144Nd isotope ratio is the key for Sm-Nd isotope method. The 143Nd/144Nd isotope ratio of geological samples varies within a small range, and thus the 143Nd/144Nd isotope ratio analysis must be precise. In order to obtain high precision and high accuracy of the analytical data, the analysis process involving Nd isotope reference material plays an important role. The previous Nd isotope reference material is neodymium oxide, which have been exhausted in recent three decades. A national reference material of 143Nd/144Nd isotope ratio was introduced in this paper, which shows sufficient homogeneity and stability. The certified value of this reference material was determined by eleven participating laboratories using MC-TIMS and MC-ICP-MS. The 143Nd/144Nd isotope ratio value for the reference material is 0.512438, with a combined expanded uncertainty (k=2) of 5 10-6. The standard solution gets certification in May, 2015 and the Serial number is GSB 04-3258-2015. The standard solution can be used for quality monitoring of the equipment calibration and analysis process during the 143Nd/144Nd ratio determination for geology, resources, ocean, environment, archaeological and other type samples. [ABSTRACT FROM AUTHOR]

In recent decades, Fe, Cu and Zn isotopes have been the hot topic with the development of analytical methods of these isotopes. However, the standard materials for isotope analysis are very sparse. There is only one Fe isotope standard material and one Zn isotope standard in The European Institute for Reference Materials and Measurements (IRMM). The former is sold out and therefor unobtainable, whereas the latter is expensive. There is one Cu isotope standard material in National Institute of Standards and Technology (NIST). In order to adapt to the development of Fe, Cu and Zn isotope analyses in China, three new standard solutions to be used as references for Fe, Cu and Zn isotopic composition have been prepared in the Institute of Geology, Chinese Academy of Geological Sciences, Beijing. Fe, Cu and Zn isotopic standard solutions are named CAGS-Fe, CAGS-Cu and CAGS-Zn, respectively. Fe, Cu and Zn isotopic compositions of these standard solutions were measured by high precision Nu Plasma High-resolution Multi-collector Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS). Three standard solutions show high homogeneity and stability by F investigation. The Fe, Cu and Zn isotopic compositions have shown no obvious variations over 38 months, indicating good homogeneity. The reference values for standard solutions and their associated uncertainties at 95% confidence level are 0.80±0.05 (δ56FeIRMM014,‰), 1.20±0.10 (δ57FeIRMM014,‰), 0.57±0.06 (δ65CuNBS976,‰), -0.77±0.10 (δ66ZnIRMM3702,‰) and -1.55±0.13 (δ68ZnIRMM3702,‰). Standard solutions can be used for instrumental calibration and analytical monitoring, which is meaningful for inter-laboratory data comparison. [ABSTRACT FROM AUTHOR]