Kelly R C, Valentour J C, Sunshine I
J Chromatogr. 1977 Aug 11;138(2):413-22. doi: 10.1016/s0021-9673(00)94976-8.
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.
