In this study, carbon microparticles (CMs) as a physical carrier to enhance the analyte transport efficiency for inductively coupled plasma mass spectrometry connected with electrothermal vaporization (ETV-ICP-MS) are proposed. Carbon microparticles mixed with samples or calibration standard solutions were dosed as a slurry into the graphite furnace. The optimization of working conditions was done for the standard solution 0.5 μg L-1 of Au and Tl. The pyrolysis and vaporization temperatures were 500 and 2700 °C for Au and 400 and 1900 °C for Tl. The optimized CMs concentration was 1 g L-1 for Au and 2.5 g L-1 for Tl. For the quantification, external calibration standard solutions were used. The result obtained for Au in the digested CRM GBW 07601 (the informatory value 2.1 ± 2 μg kg-1) was 2.2 ± 0.1 μg kg-1. The result for Tl in the digested CRM BCR 679 (the certified value 3 ± 0.3 μg kg-1) was 3.2 ± 0.2 μg kg-1 and in the slurry 2.7 ± 0.1 μg kg-1. The result for Tl in the CRM GBW 10052 (the certified value 57 ± 11 μg kg-1) was 51 ± 3 μg kg-1. The instrumental limits of detection were 0.016 ng L-1 for Au and 0.026 ng L-1 for Tl. The recoveries and repeatabilities measured on calibration standards were in the range 99-100% and 0.2-2.3% for Au and 100-111% and 2.9-6.7% for Tl.
Keywords: Analyte transport efficiency; Carbon microparticles; ETV-ICP-MS; Slurry samples; Ultra-trace analysis.
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