Study on ultra-trace metal analysis in organic solvent by re-dissolved method and direct method

In this paper, the ultra-trace metal quantification up to 1 ng/L in isopropyl alcohol (IPA) are discussed. In order to quantify the metal concentrations, “re-dissolved method” in which the solvent is completely evaporated and re-dissolved in acid for analysis with an inductively coupled plasma mass spectrometer (ICP-MS), and “direct method” in which the solvent is directly introduced into the ICP-MS are evaluated. In both methods, it was found that impurities derived from the instruments used in the analysis affect the measurement, and it was possible to reduce metal elution from the instruments by performing appropriate pre-cleaning. In addition, the analysis accuracy could be ensured. As a result, we were able to measure the metal contained in IPA the lower limit of quantification of 1 ng/L by each method. Furthermore, it was confirmed that there was no difference in the analytical values between the both methods. By properly using the two methods, we believe that it can be widely applied to the analysis of organic solvents other than IPA and the analysis of multiple samples of a single solvent.