Simultaneous Determination of ¹⁴³Nd/¹⁴⁴Nd and ¹⁴⁷Sm/¹⁴⁴Nd Ratios and Sm–Nd Contents from the Same Filament Loaded with Purified Sm–Nd Aliquot from Geological Samples by Isotope Dilution Thermal Ionization Mass Spectrometry

Isotope dilution thermal ionization mass spectrometry (ID-TIMS) is the standard technique used to achieve precise ¹⁴³Nd/¹⁴⁴Nd and ¹⁴⁷Sm/¹⁴⁴Nd isotope ratios and accurate elemental concentrations of Sm–Nd. However, in previous studies, purified Sm and Nd fractions must be individually loaded onto different filaments for their accurate determination using TIMS because of severe isobaric interferences. Thus, the classical ID-TIMS technique is time consuming and laborious. In this study, a new method is proposed, which is able to acquire both ratios of ¹⁴³Nd/¹⁴⁴Nd and ¹⁴⁷Sm/¹⁴⁴Nd and concentrations of Sm–Nd simultaneously on the same filament arrangement. The measurement time and filament consumption are reduced by 50% with the current method, and therefore, the operation cost of TIMS is significantly reduced. A mixed ¹⁵²Sm–¹⁴⁸Nd spike was employed to achieve accurate results after spike subtraction and isobaric interference corrections. Results obtained from a series of standard rock samples are in good agreement with recommended values, within ±0.003% for the ¹⁴³Nd/¹⁴⁴Nd ratio and ±1% for the ¹⁴⁷Sm/¹⁴⁴Nd ratio