The catalytic thermal conversion of organic compounds occurs at a higher temperature than that used to separate compounds on the gas chromatographic (GC) column (typically ~330-350°C, above which is generally described as high temperature gas chromatography; Blum and Aicholz 1991). Therefore, the temperature limit employed in the GC oven is not the limiting factor to achieve CSIRMS. GC oven temperatures up 420°C have been or silver ferrules) and capillary reactors suggest that this approach may regain some momentum. We hypothesised that these developments would enable us to undertake carbon CSIRMS analysis with compounds eluting from a GC column at up to 430°C.