New approach to derivatization and gas-chromatographic analysis of barbiturates.

A recently developed procedure for alkylatiori of organic acids has proven extremely successful for preparation of volatile alkyl derivatives of the barbiturates for gas-chromatographic analysis. Soluble salts are formed in a mixture of N,N-dimethylacetamide and methanol. These in turn react rapidly with alkyl iodides to form the corresponding alkyl derivatives. The butyl derivatives of barbiturates, prepared in this manner, are separable by high-resolution gaschromatography. Any of 14 barbiturates can be determined simultaneously or separately (although there is some overlap with certain uncommon barbiturates). The butyl derivatives of several barbiturates that are unresolved in the form of underived compounds or methyl esters can be resolved, thus overcoming many previous analytical limitations.