Conclusions

Improved performance has been observed using en-hanced-fluidity liquid mobile phases in every type of liquid chromatography studied to date. As mentioned earlier, typically as much as 50 mol% liquefied gas can be added to a polar solvent while still maintaining much of the solvent strength of the original organic solvent. As the solvent strength of the mixture decreases for mixtures containing more than 50 mol% liquefied gas, the chromatographic performance decreases. Extraction techniques for highly polar substances that would otherwise be very difficult to extract have been developed using enhanced-fluidity liquid mobile phases. The use of enhanced-fluidity liquids as mobile phases has also made viable a powerful technique termed critical chromatogra-phy. This separation method allows careful characterization of functionality distributions in polymers and oligomer distributions in copolymers. The precise control of solvent strength that is possible with en-hanced-fluidity liquids will allow critical chromatog-raphy to be more thoroughly studied.

Reversed-phase liquid chromatography is presently the most commonly used HPLC method. pH variation is often used to control retention in reversed-phase HPLC. While the use of enhanced-fluidity mixtures significantly improves the chromatographic performance in reversed-phase HPLC, more information is needed on pH control in these mixtures to evaluate the potential of enhanced-fluidity liquid mixtures.

Chiral chromatography is another area of separation science where enhanced-fluidity liquid mixtures may find applications in the future. Increasingly, SFC is under consideration for chiral separations. However, solvent strength often limits the utility of SFC. Enhanced-fluidity liquid mixtures have high solvent strength and therefore may be applicable to separations that SFC cannot handle.

See also: N/Chromatography: Liquid: Mechanisms:

Reversed Phases; Size Exclusion Chromatography;

Theory of Liquid Chromatography. Chromatography:

Supercritical Fluids: Theory of Supercritical Fluid

Chromatography.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook


Post a comment