Effect of Elemental Sulfur (S8) on Carbon Isotope Analysis of n-Alkanes

Stable carbon isotopes of long-chain n -alkanes in lake sediments have been used for reconstructing past environmental changes. Gas chromatography isotope ratio mass spectrometry coupled to a combustion unit is the commonly applied technique for compound-specific carbon isotope analysis. This paper shows that sulfur in the lacustrine sediment can cause severe interference during the mass spectrometric measurement, leading to significant biases in δ 13 C of n -alkane. The δ 13 C deviation could be resulted from additional 12 C 33 S + , 13 C 32 S + at mass-to-charge ratio ( m/z ) 45, and 12 C 34 S + , H 2 C 32 S + at m/z 46, respectively. Such elemental sulphur interference can be eliminated by the activated copper in the pretreatment procedure.