Minimizing LC System Volume

Description

Excess system volume can cause a number of problems with our liquid chromatography (LC). Additionally, differences in system volume from one instrument to the next can cause significant inconsistency. By making sure your connections are tight, and by using short tubing lengths and appropriate tubing internal diameters, you can get the best chromatographic performance from your systems. 

Additional Resources

• Troubleshooting HPLC – Tailing Peaks
• How do I know what the internal diameter of my LC tubing is?

Restek Recommended Tools & Parts

• LC Tubing and Connectors
• Clean-Cut Tubing Cutter

Transcript

Thanks for joining us for the latest Restek Tip, where I'll discuss the effects of system volume on your chromatographic performance. So many of us are transferring methods within our laboratory on a number of different instruments. We can start to see some pretty big differences in chromatography, such as changes in retention time, loss of peak resolution, and even some peak broadening. One thing that we don't typically think of is how is the system volume changing as we're transferring these methods? Even if we look at a difference of only about 20 microliters, we can start to see some pretty significant impact to the chromatographic performance between two instruments. Loss of resolution, changes in retention time are all things that we necessarily don't want as we're transferring these methods. There are a couple things that we can start to do to try to mitigate some of these effects as we're transferring methods within our laboratory.

One place that I like to start is with our connections. Making sure you have tight connections throughout your entire system, and also into your column, is going to reduce some additional system volume. Secondly, I'd look at the internal diameter of the tubing that I'm using in the system, making sure it's comparable to what I was using on previous systems and trying to get that system dead volume to be as similar as possible to previous instruments. Lastly, reducing the actual length of tubing that you're using. Trimming back and having those connections be as trim as possible is going to help reduce that overall peak dispersion that we can see and to overall system volume that we have.

These are some things that I usually try when I start to transfer methods from one instrument to another in my laboratory that may help mitigate some of these effects that you see from additional system volume.

Thanks for joining us today for the latest Restek Tip.