This experiment was a solid sample blank run, performed prior to
analysis of the Windjana drill sample. It revealed the continued
presence of the derivatization reagent, N-methyl-N-tert-
butyldimethylsilyl-trifluoroacetamide (MTBSTFA), in the sample
handling system. For estimation of abundances of volatile
compounds detected in EGA, the background was subtracted as a constant
value, either at the start or end of the run. Uncertainties in
abundances, deriving from statistical noise, background subtraction,
calibration factors, assumptions regarding ionization cross-sections
for the relevant compounds, and isobaric interferences, are estimated
at 10-20% of the values.