Can Dispersion be Improved?

Can Dispersion be Improved?

There are a few options available in order to improve dispersion. However, it is important to discuss why the dispersion needs to be reduced. For example, it may not be necessary to reduce the dispersion markedly for HPLC analyses which typically use >100 mm length and >3.0 mm column ID and >3 μm particle sizes. If the requirement is to use narrow bore columns or perform ultrafast analyses, then it may be prudent to reduce the bandwidth to approximately ~12 μL.

If it is necessary to improve the dispersion:

• Reduce the length of excessive tubing
• Trade blue 0.010” tubing for red 0.005” tubing
• Are column switches and valves installed? Are these essential?
• Is a low volume dispersion kit available?
• What is the flow cell design and volume?

As with most aspects of chromatography, there is a compromise. For example, by reducing the ID of the tubing, the pressure can increase substantially which may be problematic for certain stationary phases as well as causing changes in selectivity.