Sodium dodecyl sulfate, effect residues

Capillary electrophoresis has been applied by Chen and Gu (281) for simultaneous determination of oxytetracycline, tetracycline, chlortetracycline, and doxycycline residues in bovine milk. Separation was performed on a noncoated capillary column, 57 cm total length with 50 cm effective length, 75 m internal diameter (i.d.) and 375 m outside diameter (o.d.), using a mobile phase containing 10 mM sodium dodecyl sulfate, 50 mM borate, and 50 mM phosphate, pH 8.5. Under these conditions, concentrations below 10 ppb could be determined in milk using an ultraviolet spectrophotometer set at 370 nm. 

The effect of microemulsion structure on reaction rate has also been studied in relation to oxidation and reduction of cysteine residues in keratin [10]. The system sodium dodecyl sulfate (SDS)/n-pentanol/water/dodecane was chosen as a microemulsion because in this system the realm of the existence of the isotropic region in the pseudoternary phase diagram is a continuous domain, extending from the water apex to the close vicinity of the hydrocarbon-surfactant edge. It was shown experimentally that the microemulsion structure varied smoothly with composition within the isotropic region. 

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