A triple tandem columns extraction chromatography method for isolation of highly purified neodymium prior to ¹⁴³Nd/¹⁴⁴Nd and ¹⁴²Nd/¹⁴⁴Nd isotope ratios determinations

Abstract

A new separation scheme is presented for the isolation of Nd fractions highly purified from adjacent lanthanides, especially Ce and Pr, in preparation to demanding isotope ratios applications, e.g. determination of 142Nd/144Nd, or measurement of 143Nd/144Nd on very small samples by using NdO+ ion beams.

Miniaturized, rapid separation of neodymium from ultramafic and chondritic samples prior to high precision measurements of 142,143Nd/144Nd isotope ratios by TIMS

“…This work elaborates on a recently published 12 triple tandem separation scheme entirely based on extraction chromatography, enabling the analyst to isolate Nd in a form sufficiently pure to be used to determine 143 Nd/ 144 Nd and 142 Nd/ 144 Nd isotope ratios by Thermal Ionisation Mass Spectrometry. This previous procedure was designed for processing ~100 mg-sized samples of common silicate rocks.…”

“…All the chemicals (H 2 O, HF, HNO 3 , HCl, H 3 BO 3 , ascorbic acid), the labware, the three commercially available extraction chromatography resins (TRU resin, DGA resin, and LN2 resin, supplied by Triskem International, Bruz, France), and the ICP-and thermal ionisationmass spectrometers used in this study were identical to those employed in our earlier work 12 .…”

“…Isotope ratio measurements were made with a Triton TI thermal ionization mass spectrometer operated in the static multi-collection mode following methods described elsewhere. 12 Twenty-seven blocks of data, each consisting of 20 cycles of 8 seconds, were collected, with baseline measurements before each block during 30 integrations of 1 second, after deflection of the ion beam in the ion source. Between each block, the "amplifier rotation" function was used to interchange, by means of a relay matrix, the connections between the collectors and the amplifiers in order to cancel relative differences of amplifier gains.…”

“…The further separation steps aiming to isolate and further purify the Nd fraction involved the same EXC columns as those (based on LN2 and DGA resins, respectively) used in our previous work. 12 Both columns consist of disposable polyethylene pipettes (Bio-Rad DPTP Style E, ) ca. 4 mm i.d.…”

“…Then, the LREE are stripped with a small volume of acid and processed on-line, without intervening evaporation, through a tandem column extraction chromatography scheme modified from our previous work. 12 In this way, a Nd fraction purified from any Ce and Sm interfering isotopes, and suitable for high precision TIMS measurements of 142 Nd/ 144 Nd and 143 Nd/ 144 Nd isotope ratios is obtained from notoriously difficult matrices, at a strongly reduced cost in terms of time, analyst labour, and reagent volumes.…”