Gradient elution liquid

Micellar gradient elution liquid chromatography with electrochemical detection with sodium dodecyl sulfate has been used to separate phenols [186]. 

Typically, in gradient elution liquid chromatography, electrochemical detection has been difficult due to base-line shifts that result as a consequence of the altered mobile phase composition. However, a unique property of micelles allows for much improved compatibility of gradients (i.e. gradient in terms of micellar concentration or variation of small amount of additive such as pentanol) with electrochemical detectors. This has been demonstrated by the separation and electrochemical detection of phenols using micellar gradient LC (488). A surfactant (apparently non-micellar) gradient elution with electrochemical detection has also been successfully applied for the assay of some thyroid hormones by LC (491). 

Mori S (1996) Characterization of styrene-acrylonitrile copolymers by size exclusion chromatography/stepwise gradient elution-liquid precipitation chromatography. Int J Polym Anal Charact 2 185-92. 

Khaledi MG, Dorsey JG (1985) Hydro-organic and micellar gradient elution liquid chromatography with electrochemical detection. Anal Chem 57 2190-2196 Kissinger PT (1989) Biomedical applications of liquid chromatography-electrochemistry. J Chromatogr 488 31-52... 

Kirkland, J.J. Glajch, J.L. Optimization of mobile phases for multisolvent gradient elution liquid chromatography. J. Chromatogr. 1983, 255, 27. 

Fig. 1. Gradient elution liquid chromatogram of low MW cyclic formals in a BPA polyformal sample.

Fig. 20.11. Gradient elution liquid chromatography of a mixture ( blend ) of a number of copolymers. Column Supelcosil Discover Ci8, 150 mm long x 2.1 mm i.d. particle size 5 pm pore diameter 180 A temperature 25°C flow rate 0.2 ml min injection volume 5 pL sample concentration ...

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