Empower Tip: Review Window and the Processing Method

In this tip, we will learn how to create a mirror image of a chromatogram.

About once a year I receive the following question, “can I create a mirror image of my chromatogram?” The answer is YES and it is easy to do. Typically this is done as an alternate way of comparing peaks between a standard and a sample by overlaying the chromatograms.

We begin by bringing an injection into Review, open and apply the Method Set.

Derive a Channel and on the First (Only) Tab enter a constant of -1 and select the channel from the Channel drop down list.

Save the Derived Channel, add it to the Method Set along with an appropriate Processing Method.

Return to the Main Window, apply the Method Set and click the Overlay tool. We see the original chromatogram and its mirror image.

We can improve the display by going into the properties of the chromatogram and set the overlay to Make Stack Plot. (You can also clear the integration from the Edit menu.)

After processing the Sample Set, I then chose to overlay a standard and the mirror image of a sample.

Finally, we can create a Summary By All report method with a stack plot similar to what we saw in Review.

It’s that easy!