Flash alkylation for the identification of barbiturates in biological material.

The gas chromatographic identification of barbiturates isolated from biological material is not optimal, and due to their polar nature, it is difficult to obtain good resolution on most columns. To improve resolution, flash alkylation appeared to be a reasonable alternative. Methyl, ethyl, and butyl derivatives were prepared for various drugs found in the "acid-neutral" extract and the Kovats retention indices (Ir) were determined on SE-30, OV-17, and SP-2250. The Ir of the alkylated derivatives of the barbiturates are highly reproducible. One column and two alkylated derivatives can be used for the qualitative analysis of barbiturates in extracts of biological material, even when the Stas-Otto extract is used.