# Get Empowered: Review Window and the Processing Method | Tip #63, Deriving Channels

By April 4, 2018

## Tip #63: Deriving Channels in Empower (Part 16)

Welcome back to Get Empowered! In our last tip-of-the-week blog for Empower Software, we reviewed Deriving Channels when working with 3D MS chromatography data in Empower.

• Tip 47: Smooth a chromatogram by Deriving a Channel (part 1)
• Tip 48: Correct for the time offset between detectors connected in series by Deriving a Channel (part 2)
• Tip 49: Subtract a baseline from a 2D chromatogram by Deriving a Channel (part 3).
• Tip 51: Subtract a 2D baseline from 3D PDA data by Deriving a Channel (part 4).
• Tip 52: Derive MaxPlot from 3D PDA data (part 5)
• Tip 53: Derive TotalPlot from 3D PDA data (part 6)
• Tip 54: Derive RatioPlot from 3D PDA data (part 7)
• Tip 55: Derive Timed Wavelength from 3D PDS data (part 8)
• Tip 56: Derive Single Mass from 3D MS data (part 9)
• Tip 57: Derive TIC plot from 3D MS data (part 10)
• Tip 58: Improve noisy TIC plot Derived from 3D MS data (part 11)
• Tip 59: Derive MaxPlot from 3D MS data (part 12)
• Tip 60: Derive Total Plot for 3D MS data (part 13)
• Tip 61: Derive Timed Mass for 3D MS data (part 14)
• Tip 62: Create a Formula Based Derived Channel (part 15)

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.

Let me show you how it is done.

### Step 1

We begin by bringing an injection into Review, open, and apply the Method Set (Figure 1).

Figure 1

### Step 2

Derive a Channel, and on the First (Only) Tab enter a constant of -1 and select the channel from the Channel drop-down list (Figure 2).

Figure 2

### Step 3

Save the Derived Channel. Add it to the Method Set along with an appropriate Processing Method (Figure 3).

Figure 3

### Step 4

Return to the Main Window, apply the Method Set, and click the Overlay tool (Figure 4). We see the original chromatogram and its mirror image.

Figure 4

### Step 5

We can improve the display by going into the properties of the chromatogram and set the overlay to Make Stack Plot (Figure 5). (You can also clear the integration from the Edit menu.)

Figure 5

### Step 6

After processing the Sample Set, I then chose to overlay a standard and the mirror image of a sample (Figure 6).

Figure 6

### Step 7

Finally, we can create a Summary By All report method in Empower Software with a stack plot similar to what we saw in Review (Figure 7).

Figure 7

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 #64: Deriving Channels in Empower (part 17).

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