Get Empowered: Tip #214 | Working with GPC Data

By February 24, 2021

Tip #214: Axial Dispersion with GPC Data in Empower

Welcome back to Get Empowered! In the last Empower tip-of-the-week blog for Empower Chromatography Data System, we learned about interpreting the combination of both the Injection and Channel status for our data (Tip #213).

In this week’s tip, we will discuss Axial Dispersion with GPC Data.

Here’s some background information:

Axial dispersion is the broadening of a GPC peak which is caused by the chromatographic system and most of that comes from using columns with large particles, such as 20 micron. This results in modified molecular weight moments and molecular weight distribution for a broad peak. Monodisperse polymer standards are used to calculate system band broadening. Once we know the system band broadening value, we can use axial dispersion in the Processing Method which results in an estimation of true molecular weight moments and molecular weight distribution for a broad peak. (Please refer to Empower On-Line help for additional information on this topic.)

Let’s get started.

Step 1

Bring a narrow standard into Review and open a Processing Method, which is used for Relative Calibration (figure 1).

Figure 1

Step 2

Integrate the chromatogram (figure 2).

Figure 2

Step 3

From the Process menu, select ‘Quantitate Standard’ (figure 3).

Figure 3

Step 4

Calculate the average System Sigma (this could be done with a Simple Custom Field) (figure 4).

Figure 4

Step 5

Modify the Processing Method on the Axial Dispersion tab to include the Axial Dispersion Correction and enter the value from Step 4 into the Sigma (ml) field (figure 5).

Figure 5

Step 6

Save all changes to the Processing Method and process the Sample Set in the normal fashion (figure 6).

Figure 6

Step 7

Results now reflect the use of Axial Dispersion (figure 7).

Figure 7

Step 8

A simple report table displays the difference in the results with and without the Axial Dispersion correction (figure 8).

Figure 8

It’s that easy!

Final Note: You can use either the Pro or QuickStart interface for this tip.

Please rate this Empower Tip of the Week

Next week in Empower Tip #215 – We will learn how to clear extracted channels when working with 3D data in the Review Window.

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Categories: Empower Tips