Packed Columns

The equilibrium distribution of analyte between the two phases should be independent of sample size.

However, as sample size increases isotherms become nonlinear and peaks become broader and distorted, which leads to reduced resolution. A column is regarded as overloaded if its efficiency is reduced by 10%. The approximate maximum vapour volume (Vmax) of an individual solute not leading to detectable peak broadening can be calculated from:

where VR is the retention volume and N is the number of theoretical plates.

For a component eluted with a retention volume of 150 mL (after 5 min at 30 mL min"1) from a packed column of 3000 plates, Vmax is approximately 50 |L, equivalent to 0.1 |L liquid.

More empirically, initial bandwidth should be not more than a tenth of the width of the narrowest peak and the smaller the sample the better the chromatog-raphy. The analyst should inject microgram quantities. Since 0.1 |L corresponds to 100 |g for a liquid of unit density, dilute solutions are necessary if only a few micrograms are required.

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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