In "Idiots look at Data", we wondered what Shackleton did to be sure he was looking at the right thing. The answer seems to be on GDC 1100. We learn that he did the GCMS at one site, then shipped the samples to another site, not unlike the two machine setup at LNDD over a longer distance.
Confirmation of identity of steroids in extracts.It is not clear to us from reading this if impact MS data were acquired and analyzed at the GC/C/IRMS site, or only from the GC/MS site.
Prior to sending the first samples for GC/C/IRMS analyses in England, the identities of the principal components of the chromatogram were confirmed by GC/MS. This was carries out on a Hewlett-Packard 5970 instrument housing a 15 meter DB1 capillary column. The peaks chosen for GC/C/IRMS analyses had retention times and electrion impact mass spectra identical to those of 5a- and 5b-androstanediol diacetate and pregnanediol diacetate. Reference steroid for these compounds were also analyszed on the GC/C/IRMS instrument using both DB1 and DB17 columns, and these gave identical retention times to the urinary steroids. Pregnanetriol could also be analyzed by GC/C/IRMS.
I'm not smart enough to tell if Shackleton's chemistry is the same as what we know of LNDD's.