Simultaneous measurement stable and radiogenic Nd isotopic compositions by MC-ICP-MS with a single-step chromatographic extraction technique

Abstract

Removing the interferences such as Ce on Nd isotopes during column chemistry is hardly achieved due to their similar properties. In this study, we established a simple but efficient Nd...

Ce and Nd stable isotope purification and determination of geological samples by MC-ICP-MS

“…8 Generally, Ce and Nd in natural rocks are purified by completely different methods, including four elution schemes (Table 1): (1) the classical two column AG50W + LN, 36,39,40 tandem column TRU + LN I 8,41,42 or TRU + LN II; 43,44 (2) α-HIBA technique; 3,31,45,46 (3) the NaBrO 3 method, also called liquid–liquid micro-extraction (LLME); 2,47–51 (4) the single TODGA resin column. 52–55 For the elution scheme (1), this method has not been applied to the study of Ce and Nd stable isotopes because 100% yield with perfect Ce–Nd separation is not achieved well (see Table S1 in Bai et al 55 ). For example, Pin and Gannoun 43 presented a triple tandem column extraction for the isolation of highly purified Nd, but the chemical recoveries were between 80% and 90% in natural rocks.…”

“…The incomplete Nd yield during chemical separation will result in mistaken information for stable Nd isotopic analyses when not using a double spike. 31,55 For the elution scheme (2), in an original paper, Tanaka and Masuda 3 presented a protocol for Ce separation using cation-exchange column chromatography with an α-HIBA reagent. This method was subsequently applied by several researchers to separate Nd.…”

“…In fact, low yield and residual isobaric elements, such as Ce in Nd cuts, have been reported, 45,46 which can severely impact the accuracy and precision of the measurements of stable Ce and Nd isotopes. 12,55 In addition, a long and thin column (0.2 cm × 20 cm) 45 was used in their method, which is time-consuming (∼4 days). 31,46 For the elution scheme (3), Rehkāmper et al 47 reported a two-phase micro-extraction technique for the separation of Ce from the other LREEs, which can be called the NaBrO 3 method 57 or liquid–liquid micro-extraction (LLME).…”

“…For elution scheme (4), some researchers recently reported the use of a TODGA resin column to purify Ce 12 or Nd, 52–54 which has a very high efficiency for LREEs. For example, Bai et al 55 established a single TODGA resin column to separate Nd from the other REEs. However, this method cannot be applied to purify Ce for the determination of Ce isotopic compositions because of the overlapping La–Ce–Pr bands (see Fig.…”

“…However, this method cannot be applied to purify Ce for the determination of Ce isotopic compositions because of the overlapping La–Ce–Pr bands (see Fig. 1 in Bai et al 55 ). Residual La can cause large isobaric interference on Ce isotopes, and residual Pr may generate molecular interference from 141 PrH on 142 Ce, 12,40 and achieving very high Ce purity is of paramount importance.…”