TY - JOUR A1 - Heinrich, Hans-Joachim A1 - Kipphardt, Heinrich T1 - Application of methane as a gaseous modifier for the determination of silicon using electrothermal atomic absorption spectrometry N2 - For determination of silicon in aqueous solutions by electrothermal atomic absorption spectrometry methane/argon mixtures as a gaseous modifier were applied during the pyrolysis step to improve the analytical performance. The beneficial effects observed on thermal stabilization, signal enhancement and shape of absorbance signals were attributed to the thermal decomposition products of methane, which were hydrogen and carbon black (soot). Using a 5% CH4 mixture with argon, the optimized pyrolysis and atomization temperatures were 1350 °C and 2450 °C, respectively. A flushing step following the pyrolysis was mandatory to avoid background absorption and accelerated deposition of pyrolytic graphite. Characteristic masses of 50 and 30 pg were obtained for standard transversely heated graphite atomizer (THGA) tubes and end-capped THGA tubes, respectively, which were lower than with other previously applied modifiers. A limit of detection of 0.2 µg L- 1 (3 s, n = 10) has been obtained. In addition, this gaseous modifier did not contribute to contamination which often was significant when a liquid modifier solution was co-injected. The proposed method has been applied to the determination of silicon in ultrapure water, nitric and hydrochloric acids. KW - Electrothermal atomic absorption KW - Spectrometry KW - Silicon determination KW - Methane KW - Modifier KW - Ultrapure reagents PY - 2012 U6 - https://doi.org/10.1016/j.sab.2012.04.001 SN - 0584-8547 SN - 0038-6987 VL - 70 SP - 68 EP - 73 PB - Elsevier CY - Amsterdam AN - OPUS4-26050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heinrich, Hans-Joachim A1 - Bremser, Wolfram T1 - Einsatz der direkten Feststoff-Graphitrohrofen-AAS bei der Bestimmung von Elementspuren in Graphitpulvern T2 - 4. Anwenderseminar direkte Feststofftechniken CY - Berlin, Germany DA - 2012-05-10 PY - 2012 AN - OPUS4-25946 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -