Separation Quality

The general object of a chromatographic separation is to obtain an acceptable separation (resolution)

between all components of interest in a mixture within the shortest possible time. The resolution between two peaks in a chromatogram depends on how well the peak maxima are separated and how wide the two peaks are. This can be expressed numerically by the ratio of the separation of the two peak maxima divided by the average peak widths at their base. Baseline separation of the peaks is achieved at a resolution of about 1.5 but a value of 1.0, representing about 94% peak separation, is taken as an adequate goal for components that are difficult to separate. Resolution is also simply related to the properties of the chromatographic system. For this purpose it is convenient to consider a simple model of a three-component mixture in which the optimum column length is dictated by the number of theoretical plates required to separate the two components that are most difficult to separate, and the total separation time is dictated by the time required for the last peak to elute from the column. The resolution of the two peaks that are most difficult to separate is then related to the column variables by:

where kAV is the average value of the retention factor for the two peaks, or in an approximate form by:

for peaks with approximately equal base widths in which the elution order of the peaks is k2 > k1.

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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