Capillary electrochromatography is a highly promising technique that couples the advantages associated with capillary electrophoresis with those of HPLC. Theory predicts a 2- to 3-fold increase in efficiency on going from an HPLC pressure-driven system to a CEC electrically driven system. Because there is no pressure drop across the capillary column in CEC, it is possible to use long columns that would require prohibitively high pressures if used in pressure-driven systems. Examples have been given of separations by CEC on 40 cm long capillaries giving efficiencies of 4x105 plates m"1. This is equivalent to 160 000 effective plates, which is a factor of about 15 times greater than that currently available in HPLC.

The development of stationary phases that allow CEC to be used over a wider pH range will allow the analysis of mixtures containing neutral and charged

Figure 21 CEC separation on a nonporous phase, Micropell-C18. Voltage, 30 kV; temperature, 30°C; detection at 210 nm; carrier, 70% acetonitrile/30% 2 mmol L"1 Na2HP04, pH 7.0; injection, 10 s at 2 kV.

species and will offer a viable complementary technique to HPLC and capillary electrophoresis.

See also: N/Chromatography: Liquid: Column Technology; Mechanisms: Reversed Phases; Detectors for Capillary Electrophoresis; Micellar Electrokinetic Chromatography. III/Chiral Separations: Capillary Electrophoresis.

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.

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