SIMULTANEOUS DETERMINATION OF METHYLENE VIOLET, HALOGENATED METHYLENEVIOLET AND THEIR PHOTOPRODUCTS IN THE PRESENCE OF DNA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING AN INTERNAL SURFACE REVERSED-PHASE COLUMN

A simple and rapid isocratic high-performance liquid chromatographic m ethod for the analysis of methylene violet, a neutral phenothiazine dy e, in the presence of DNA has been developed. These chromatographic co nditions are also applicable to its N-demethylated, bromo and iodo ana logs. The method utilizes an internal surface reversed-phase column an d a mobile phase consisting of 20% acetonitrile in 50 mM phosphate buf fer (pH 7.0) and detection at 280 nm. Under these conditions all five dyes are well resolved from one another and from the faster migrating DNA. The effects of organic modifiers, ionic strength and pH of the bu ffer on the capacity factors of the dyes have been investigated. The m ethod has successfully been applied to detect the photoproducts of met hylene violet and its bromo analog in the presence of DNA without remo ving the biopolymer from the reaction mixture. (C) 1997 Elsevier Scien ce B.V.