Get Empowered: Empower User Question | Tip #222, Using the Compare Window in Empower
Tip #222: Empower User Question: Aligning chromatograms using the Compare window in Empowerer
Welcome back to Get Empowered! In the last Empower tip-of-the-week blog for Empower Chromatography Data System, we learned about Durable Data (Tip #221).
In this week’s tip, we will answer an Empower user question regarding aligning peaks between chromatograms where the retention times have shifted.
Q: It is not unusual to have a small amount of retention time shifts from injection to injection. How can I be sure that the peaks from chromatogram to chromatogram are the same so that I can track them with this shift in retention time?
Great question. We can solve the problem using the Compare window.
Let’s get started.
Step 1
Highlight the channels of data, right click, and select ‘Compare’ (figure 1).

Figure 1
Step 2
The Compare window opens displaying an overlay of the chromatograms (figure 2).

Figure 2
Step 3
Click the ‘Individual Plot’ tool and a stack plot is displayed (figure 3).

Figure 3
Step 4
Click the ‘Alignment Markers’ tool to display the alignment markers in the chromatograms (figure 4).

Figure 4
Step 5
Move the ‘first marker to the first peak’ in each chromatogram and the ‘second marker to the last peak’ in each chromatogram (figure 5).

Figure 5
Step 6
Click the ‘Align Chromatograms’ tool to align the peaks (figure 6).

Figure 6
Step 7
Click the ‘Compare Main Window’ tool to display the aligned chromatograms in one window (figure 7).

Figure 7
It’s that easy!
Final Notes:
- If you zoom in on the baseline of the chromatograms after Step 6, the resulting view in Step 7 will remain zoomed in. This will help when looking at small impurity peaks.
- You can use either the Pro or QuickStart interface for this tip.
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Next week in Empower Tip #223: We will resume our series on working with Export Methods (Part 3).
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