Chemical structure and purity of dyes used in lymphograms

Because of confusion in the literature, studies were performed on several samples of patent blue violet and Alphazurine 2G to determine their chemical structure and purity. Nuclear magnetic resonance studies revealed that three distinct compounds and one mixture had all been labeled as the same compound. The purity of the dyes varied from batch to batch, as shown by thin-layer chromatography. Caution should be exercised in the use of these dyes for lymphograms.