Direct determination of trace amounts of silicon in polyamides by means of solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry

Abstract

In this work, a method has been developed for the fast and reliable determination of silicon in polyamides (two samples with silicon contents of 10 and 50 µg g−1 were analyzed) by means of solid sampling electrothermal vaporization ICP-MS. For all silicon isotopes, the occurrence of spectral interferences was studied as a function of the vaporization temperature. The benefits of the use of palladium as a chemical modifier were investigated. Finally, a vaporization temperature of 2400 °C, monitoring of 29Si+ and the addition of 1 µg of palladium were found to be the optimum conditions for the determination. The method finally proposed shows very interesting features for this particular element: the ability to use aqueous standard solutions for calibration, a low sample consumption (a few milligrams only), a high sample throughput (20 min analysis time per sample), a low limit of detection (0.3 µg g−1) and a reduced risk of analyte losses and, particularly, of contamination. Additionally, the approach also exhibits multi-element capabilities.