Isotope analysis of nanogram to sub-nanogram sized Nd samples by total evaporation normalization thermal ionization mass spectrometry

• DOI: 10.1016/j.ijms.2017.11.014
• Publication Date: 2017-11-24T04:17:12Z
• Authors: Shigeyuki Wakaki; Tsuyoshi Ishikawa
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

Abstract This paper presents 143Nd/144Nd analysis of nanogram to sub-nanogram sized Nd samples using total evaporation normalization thermal ionization mass spectrometry (TEN-TIMS) with Nd+ ions. Total integration of high and stable Nd+ ion signals produced by dynamic filament-current control until sample burnout in combination with a long baseline measurement achieved reasonably high signal to noise ratios even for very small samples. Repeated analyses of an Nd isotopic reference material JNdi-1 with Nd sample sizes of 2, 1, 0.5, and 0.1 ng all yielded consistent 143Nd/144Nd values with external precisions of 42, 62, 93, and 184 ppm (2RSD), respectively. Errors were as small as analytical error limits defined by counting statistics. Repeated analyses of basalt (JB-2) and coral (JCp-1) samples with 0.6–1.2 ng of Nd after processing with low-blank Nd separation chemistry designed for small samples also gave 143Nd/144Nd values consistent with those given by large-sized sample analyses, and the external precisions were comparable to the JNdi-1 analyses. The TEN-TIMS technique was capable of analyzing 143Nd/144Nd ratios of geological materials with sample sizes as small as 0.5 ng of Nd with a precision of ±1 e-unit or better.