Extractive alkylation was used to determine intact pemoline in serum and urine. Pemoline was extracted into methylene chloride as an ion-pair with tetrapentylammonium hydroxide under alkaline conditions. Evaporation of the solvent at 70 degrees in the presence of methyl iodide yielded the N,N-dimethylpemoline derivative. GLC analysis was performed on a 5% FFAP column with nitrogen-specific detection. Sensitivity was 0.05 microgram/ml with 1 ml of urine of serum. Calibration curves were linear to at least 4 microgram/ml with serum and 15 microgram/ml with urine. Precision was excellent with a pooled relative standard deviation of +/- 7.5% for serum samples in a 0.1-4 microgram/ml range.