Get Empowered: Review Window and the Processing Method | Tip #133, GPC/SEC Data

By August 7, 2019

Tip #133: Working with GPC/SEC data in Empower Software (Part 10)

Welcome back to Get Empowered! In the last Empower tip-of-the-week post for Empower Chromatography Data Software,  we learned about using Molecular Weight Markers in the Processing Method (Tip #132).

In this week’s tip, we will conclude our series on working with GPC/SEC data. I will answer a common question regarding peak detection and integration when working with GPC/SEC data.

Q: Which algorithm should I use: Apex Track or Traditional?

A: It really depends on your chromatography

Let’s get started.

Step 1

We begin by developing a Processing Method using the Apex Track algorithm. The first standard is fine
(figure 1).

Empower Tips: Apex Track algorithm | Figure 1

Figure 1

Step 2

The second standard has a negative dip after the last peak at 3.324 minutes, which causes the baseline to be drawn in an undesirable way (figure 2).

Empower Tips: Negative dip/undesirable baseline | Figure 2

Figure 2

Step 3

Next, develop a Processing Method using the Traditional algorithm and the integration doesn’t look any better (figure 3).

Empower Tips: Processing Method using the Traditional algorithm | Figure 3

Figure 3

Step 4

There are some integration events which are unique to the Traditional algorithm that can help in cases like this, namely ‘Forward Horizontal by Time’ which forces the baseline horizontally across, thus improving the baseline. Using the Show Events tool, you can view the integration events in the chromatogram (figure 4).

Empower Tips: View ‘Forward Horizontal by Time’ | Figure 4

Figure 4

Step 5

By entering a time for the event to start (as in figure 4), the baseline extends horizontally from the start point. If you enter a time for the event to start and a time for it to stop, then the baseline extends horizontally from the start point to the stop point as seen in chromatogram 1. Notice the value is used if the baseline is noisy. Empower uses the start time and then the value creates a window of time around that start time from which it calculates noise. The baseline is then drawn horizontally from the start point, using the average baseline value as seen in chromatogram 2 (figure 5).

Empower Tips: Empower uses start time/ the value creates a window of time | Figure 5

Figure 5

It’s that easy!

Final note:  This procedure can be followed using the QuickStart or Pro interface.


Please rate this Empower Tip of the Week

Next week in Empower Tip #134 – Next week we will begin a new series on calculating peak purity when working with PDA data (Part 11).

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Categories: Empower Tips