DEVELOPMENTS IN THE QUANTITATIVE AND SEMIQUANTITATIVE DETERMINATION OF TRACE-ELEMENTS IN CARBONATES BY LASER ABLATION INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY

Standards for fully quantitative laser ablation inductively coupled plasma mass spectrometric analysis of carbonates have been produced by adding elemental standard solutions to a carbonate powder base, making possible the production of standards of low concentration (as low as 10 ppm of addition) with high internal precision reflecting homogeneity. Such low concentration standards would be impossible to produce by additions of elemental oxide powders to a carbonate matrix. A single internal standard analytical technique (so called 'semiquantitative' analysis) has been developed based on one multi-element standard which is used to determine the instrument response across the mass range 6-240 u. Results for this technique are generally within +/-10% of accepted values for geological reference carbonate materials [e.g., Bureau of Analysed Samples, British Chemical Standard, Reference Material 393 (Limestone): Mg certified 900 ppm, analysed 892 ppm; Sr certified 160 ppm, analysed 186 ppm]. Semiquantitative analysis has the advantages of requiring less time to standardize the instrument and less data processing.