title: Solvent suppression of the decomposition of phenobarbital during on-column methylation with trimethylanilinium hydroxide.
abstract: Gas-liquid chromatographic (GLC) analysis of phenobarbital by on-column methylation with trimethylanilinium hydroxide gives rise to a major decomposition product, N-methyl-2-phenylbutyramide, in addition to the methylated barbiturate, N,N'-dimethylphenobarbital. This reaction occurs nearly exclusively in the solution phase in the injection port of the gas chromatography. A mechanism for the decomposition reaction consistent with the available information is presented. This decomposition is shown to be inhibited by certain solvents and this effect forms the basis of a new analytical technique for the simultaneous GLC analysis of phenobarbital, primidone, and diphenylhydantoin.
mesh_terms: D000814:Aniline Compounds; D055598:Chemical Phenomena; D002621:Chemistry; D002849:Chromatography, Gas / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D008745:Methylation; D010634:Phenobarbital / Q000097:blood*
chemical_list: D000814:Aniline Compounds; D007202:Indicators and Reagents; D010634:Phenobarbital