Application of combined liquid chromatography/mass spectrometry (LC/MS): analysis of petroporphyrins and meibomian gland waxes.

Application of the moving belt LC/MS interface is illustrated by two diverse examples, one from the field of petroporphyrin chemistry, the other, a sample of high molecular weight waxes from the steer meibomian gland (eye). Petroporphyrins are difficult of convert to derivatives suitable for GC analysis and the advantages of analysis by a combined separation/identification method are well demonstrated by the LC/MS runs. High molecular weight waxes can be saponified and derivatized for other analyses such as GC and GC/MS, but information regarding the distribution of alcohol and acid in the combined state is destroyed. This study shows that such information can be obtained by a combined LC/MS analysis without chemical manipulation of the sample.