On-line double isotope dilution laser ablation inductively coupled plasma mass spectrometry for the quantitative analysis of solid materials

• Development of a double IDMS strategy for direct solid analysis by LA-ICP-MS.
• The proposed method requires the sequential analysis of the sample and a standard.
• The previous characterization of the spike solution is not required in double IDMS.
• Quantitative bulk analysis of Sr, Rb and Pb were performed in silicate glasses and powdered samples.
• Powdered samples were analyzed as pressed pellets and glasses prepared by fusion.

We report on the determination of trace elements in solid samples by the combination of on-line double isotope dilution and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The proposed method requires the sequential analysis of the sample and a certified natural abundance standard by on-line IDMS using the same isotopically-enriched spike solution. In this way, the mass fraction of the analyte in the sample can be directly referred to the certified standard so the previous characterization of the spike solution is not required. To validate the procedure, Sr, Rb and Pb were determined in certified reference materials with different matrices, including silicate glasses (SRM 610, 612 and 614) and powdered samples (PACS-2, SRM 2710a, SRM 1944, SRM 2702 and SRM 2780). The analysis of powdered samples was carried out both by the preparation of pressed pellets and by lithium borate fusion. Experimental results for the analysis of powdered samples were in agreement with the certified values for all materials. Relative standard deviations in the range of 6–21% for pressed pellets and 3–21% for fused solids were obtained from n = 3 independent measurements. Minimal sample preparation, data treatment and consumption of the isotopically-enriched isotopes are the main advantages of the method over previously reported approaches.

Development and validation of a new on-line double IDMS methodology to achieve an accurate, precise, and time-effective strategy for direct determination of trace elements in solid samples by LA-ICP-MS.Figure optionsDownload as PowerPoint slide