Determination of Titanium in Fine Gold by Elctrothermal Atomic Absorption Spectrometry

Abstract

The transversely heated graphite atomizer (THGA) proved to be better suited to the task of determining Ti in gold owing to the reduction in analyte carry-over compared with a Massman type atomizer. Carry-over was also reduced by using a second maximum power atomization step (2600 °C) as a clean-out step and cycling through the temperature program twice with no sample between solution samples. Platform atomization with the THGA was preferred because of the slightly higher observed sensitivity, especially as increasing amounts of gold matrix per aliquot attenuates the analytical signal. The tube lifetime was lower owing to the high temperatures and long atomization times (10 s). The limit of detection (3 σ ) was estimated to be 5 µg l ^-1 based on 20 µl aliquots containing 40 µg of gold. The accuracy of the method was verified by determining titanium in gold reference materials with known concentrations of titanium. Typical precision was approximately 4% (RSD) for 0.2% gold solutions containing 42 µg l ^-1 Ti (20 µl aliquot).