Resolution of quaternary mixture of ionic dyes on biphasic alumina-keiselguhr thin layer plate: Synergistic effect of cationic-nonionic surfactants

By Ali Mohammad, Nazrul Haq


A new green thin layer chromatographic system comprising of biphasic alumina-keiselguhr (1:1) as stationary phase and equal volume mixture of 1% (w/v) aqueous solution of cationic surfactant (cetylpyridinium bromide) and nonionic surfactant (Brij-35) in 1:1 ratio as mobile phase has been proposed for the analysis of ionic (anionic and cationic) dyes. From the point of view of resolution of dyes, mixed alumina-keiselguhr has been found more effective than it’s individual components. In the same way, synergism between cationic and nonionic surfactant proves to be more efficient for the separation of dyes from their quaternary mixture than the individual surfactants. Effect of presence of heavy metal cations as impurities in the sample on the separation was examined. The limits of detection of bromocresol green, malachite green, rhodamine B and congo red were 0.27, 0.19 , 0.21  and 0.23 µg respectively. Chromatographic parameters like ?RF, separation factor (a) and resolution (RS) were calculated for the separation of bromocresol green- malachite green- rhodamine B-congo red. The proposed method is simple, rapid and free from the use of volatile organic solvents


Key Words : Thin layer chromatography, surfactant, green eluents, separation, dyes.


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