An improved solvent extraction procedure for Re isotopic measurements

Abstract

In this paper, we present an improved solvent extraction method for the chemical isolation of Re from the sample matrix using ammonia (NH3·H2O) and butanone instead of the traditional extraction method using NaOH and acetone. With this method, no sodium is introduced, and thus, no subsequent further purification is required prior to inductively coupled plasma mass spectrometry (ICP-MS) measurements. For the extraction, when the volume ratio of NH3·H2O to butanone was 1:2, with 4 mL of NH3·H2O and 8 mL of butanone, the recovery was as high as greater than 90%. The effects of the extraction time, the centrifugal speed, and the centrifugal time were investigated. Re can be efficiently extracted into the butanone in only 1 min, and a centrifugal speed of 2000 r/min for 5 min was used to separate the butanone from the NH3·H2O. We compared the three chemical methods (anion exchange resin, acetone–NaOH mixture, and butanone–NH3·H2O mixture) for a variety of sample matrixes (sulfides and rock sample). The results show that the new method can completely separate the Re from the matrix with a low blank (2–5 pg). Finally, the proposed method was verified using reference materials (Henderson HLP, JDC, JCBY, and UB-N), and the analytical results were found to be in good agreement with the previously reported data.