Uli,

You probably know this already, but we use a programmable temperature
vapourising injector (PTV) so we can keep things hot during injection and
shift the steroids onto the GC column using a transfer pressure. This allows
us to analyse underivatised steroids. Comparisons with direct combustion
results of steroid standards indicate that fractionation is minimal. The
clean traces we get also indicates that decomposition in the injector is not
occurring.

I realise that this doesn't answer your on-column question, but it has
relevance to your splitless problems.

Mark

-------------------------------------------------------------------
Mark Sephton,
Planetary Sciences Research Institute,
Open University,
Milton Keynes,
MK7 6AA, UK.
Tel: + 44 (0)1908 659358
Fax: + 44 (0)1908 655910
Email: [log in to unmask]
-------------------------------------------------------------------