抄録
Sulphide and sulphate minerals mixed with V2O5 and SiO2, were heated in a vacuum at 950°C for 15 minutes. The evolved SO3 was converted to SO2 by reaction with metallic Cu for sulphur isotope determinations. This technique yields SO2 of consistent oxygen isotope composition regardless of whether sulphide or sulphate is converted. The reproducibilities of sulphur conversion and δ34S values were 98 ±5% and ±0.2‰, respectively. The technique is particularly suitable for small samples. Successful isotope determinations have been obtained with natural samples containing less than 1 mg S. In some cases, variations in δ34S of 2‰ have been found for single grains analysed from a small specimen.
