Wednesday, January 29, 2014
Comparative Analysis of Biological Sphingolipids with Glycerophospholipids and Diacylglycerol by LC-MS/MS
Uh oh! This isn't proteomics! I'm trying to expand my range a little. Last summer I had the opportunity to work with some lipidomics experts and it is something that I find interesting. I also still think that it is the most difficult type of experiment I have ever seen performed with LC-MS.
This paper stands out to me because of the simplicity of it. Btw, the article title is the same as the title of this blog post, and you can read it (open access!) here.
In this study, this team of researchers in Japan start out with a series of known controls for their lipids and work on simplifying the sample prep and LC conditions to be both simple (no derivatizations, no crazy fancy columns) and still robust. Typically, compounds of this type are derivatized or at least alkylated before attempting LC-MS analysis. Turns out it isn't necessary! Now, it's still tough to extract the lipids and the sample prep still sounds like a bit of a nightmare what with the multiple solvent extractions and all, but it could be worse.
The LC-MS/MS conditions are described in painstaking detail to the point that I think I could set this experiment up without ever wondering "what do they mean here?" The LC was a Thermo Ultimate 3000 running a standard PepMap C-18 column into a HESI source attached to a TSQ Vantage with multiple SRM targets.
The big question? Do these simplifications have negative effects on the specificity of this analysis for the lipid compounds of interest? I guess not, because they are able to extract, identify, and quantify these compounds in biological samples and their measurements correlate perfectly to phenotypic differences between these samples.
Awesome study that makes LC-MS analysis of lipids seem a little less daunting. Thanks to @BioProteomics who Tweeted a link to this study on 1/27!