[Phenobarbital determination using direct densitometry of thin-layer chromatography]

A report on the determination of phenobarbital in model specimens of plasma and blood using direct densitometry of thin-layer chromatograms, namely by measurements of fluorescence quenching using remission technique following previous conversion of phenobarbital to sodium salt. Phenobarbital is extracted by three fundamentally different techniques, the results of estimation are given statistical evaluation, and the yield of each of the techniques is compared. Since the processing of 1 ml serum still allows the estimation of quantities as low as 1 microgram per stain the proposed method can be recommended for the determination of toxic levels of phenobarbital in plasma or in blood.