Capillary electrophoretic separation of vitamins in sodium dodecyl sulfate containing buffers with lower aliphatic alcohols and n-hexane as organic modifiers.
The effect of lower organic alcohols as co-surfactants (methanol, ethanol, n-propanol, isopropanol, propanediol, n-butanol and isoamylalcohol) and n-hexane as an organic modifier in 12.5 mol/l phosphate buffer with varying SDS concentration was investigated using a set of vitamins and p-hydroxybenzoic acid as the test mixture. It was demonstrated that optimum separations can be achieved particularly at high concentrations of the surfactant; the selectivity can be changed by adding a co-surfactant; while propanol and isopropanol show the same properties as co-surfactants, the most efficient alcohols were isoamylalcohol and propanediol. n-Butanol was capable of selective separation of p-hydroxybenzoic acid in the test mixture. Addition of ethanol appears most effective at higher concentrations (while all the other alcohols are effective already at 5% concentration, the best results with ethanol were obtained when it constituted 20% of the background electrolyte). 5% Concentration of methanol resulted in poor separation of the test mixture, however if 300 microl/10 ml of hexane were added to 20 mmol/l SDS containing phosphate buffer, the resulting separation was practically the same as with 50 mmol/l SDS.
Bellini
M S
MS
Glaxo Wellcome SpA, Verona, Italy.
Manetto
G
G
Deyl
Z
Z
Tagliaro
F
F
Miksík
I
I
D000438:Alcohols / Q000737:chemistry*; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D006586:Hexanes / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D014815:Vitamins / Q000302:isolation & purification*
D000438:Alcohols; D002021:Buffers; D006586:Hexanes; D014815:Vitamins; C026385:n-hexane; D012967:Sodium Dodecyl Sulfate