Determination of 8-hydroxyquinoline sulfate in tuberculin solutions by planar and high performance liquid chromatography

TLC and HPLC methods for the determination of the preservative, 8-hydroxyquinoline sulfate in PPD-T tuberculin solution were developed. The planar chromatography method involved separation of 8-hydroxyquinoline sulfate on a TLC plate using a butyl-acetate: formic acid :2-propanol mobile phase, detection and quantitation by densitometric scanning. The HPLC method was on a LiChrosorb RP-18 column with acetonitrile-water (65:35 v/v) mobile phase, adjusted to pH 3.05 by phosphoric acid. Linearity, reproducibility and accuracy were found to be satisfactory. Under selected conditions, the limit of detection (LOD) of both methods was similar - about 25 ng