# Get Empowered: Review Window and the Processing Method | Tip #62, Deriving Channels

By March 28, 2018

## Tip #62: Deriving Channels in Empower (Part 15) 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)

In this tip, we discuss a feature that was introduced with Empower 3 Feature Release 4 (FR4) called Formula Based Derived Channel.

Deriving a Channel lets us mathematically combine two channels of data. What if we wanted to combine more than two channels? There is a relatively new feature that lets us combine up to 10 channels of data.

Let me show you how it is done.

### Step 1

We begin by bringing four individual 2D MS channels (SIR channels) into Review and overlay in a stack plot (Figure 1). What we want to do is combine these four channels into one channel so that we can, for example, perform impurity calculations on the sample much like we did in earlier tips.

### Step 2

Exit out of Review, bring the injection containing the four channels into Review, and go to the Method Set window. Right-click on Derived Channels, select New, and then select Formula Based Derived Channel (Figure 2).

### Step 3

The Formula Based Derived Channel dialogue box opens (Figure 3).

### Step 4

We start by defining our variables, one variable per channel. In the Variable field, select A from the drop-down list (Figure 4).

### Step 5

In the Channel field, select the first SIR from the drop-down list (Figure 5).

### Step 6

Select all variables and all channels for the four channels to be added together (Figure 6).

### Step 7

In the formula field, enter A+B+C+D (Figure 7).

### Step 8

Click OK. Enter a name for the Derived Channel and select the Processing Method (Figure 8).

### Step 9

Return to the Main Window and Apply the Method Set (Figure 9). Notice the four peaks are now in one chromatogram and the Channel Description reflects the combination.

### Step 10

Click the Peaks tab. Now we see the results for the Impurity Analysis (Figure 10).

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 #63: Deriving Channels in Empower (part 16).

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