lactic acid vs acetic acid retention times

[siddana2005]

in a partcicular GC method (FID column) What will be the RT relation between Lactic Acid and Acetic Acid i mean which will be higher and which will be lower. can any one please help me? what is the main property of a component that determines its RT?

[Peter Apps]

I doubt that lactic acid will elute as a recognisable peak in GC. Retention depends on the partition of the compound between the stationary phase and the carrier gas. With non-polar phases higher molecular weight compounds elute later. With polar phases, compounds that have polar functional groups elute later than compounds with the same molecular weight but with no polar groups.

Peter

[Consumer Products Guy]

And lactic acid typically contains a significant amount of its self-ester. Even the "beloved" USP-NF assay in its monograph takes that into account.

[chromatographer1]

Theree is a chromatogram of lactic acid on Supelco's web site.

The lactone elutes more quickly and the dimer elutes later.

best wishes,

Rod