Determination of the enantiomeric purity of levodopa, methyldopa, carbidopa and tryptophan by use of chiral mobile phase high-performance liquid chromatography.

Chiral mobile phase high-performance liquid chromatography was used successfully for the determination of the enantiomeric purity of levodopa, methyldopa, carbidopa and tryptophan. The method investigated uses phenylalanine and copper sulfate in the mobile phase and a C18 column. Linearity, precision, accuracy, detection limit and interference from expected impurities were assessed. The method is also applicable to the measurement of enantiomeric purity in levodopa tablets and capsules.