Hi Primus,
Our high temperature G.C. columns will show all volatile organics up to roughly 1,500 molecular weight and sometimes higher (depending on the chemistry). This includes all typical base oils such as PAOs up to and including 10 cSt, ANs up to and including 12 cSt, esters up to and including 15 cSt, and mineral oils up to and including 600N. It can also see the light end portions of heavier organics, enough to allow identification in many cases. In short it can easily see about 90% of a typical motor oil, missing only some additives such as the VII solids, portions of organometallic detergents and polymeric dispersants, and other heavy compounds such as some Ketjenlubes. Each base oil has its own distinct thumbprint which is easily readable by one experienced in motor oil analysis.
M1 is reported to contain some high viscosity SuperSyn PAOs at an additive dosage, and these will not show. Hence if M1 has say 10% of heavy PAO then I will likely be looking at 80% of their oil instead of 90%.
Tom