Get Empowered: Review Window and the Processing Method | Tip #40

By October 25, 2017

Tip #40: Calculating impurities in samples (Part 1)

Welcome back to Get Empowered! In the last Empower tip-of-the-week blog for Empower Software, we explored the final part in a series on how to working with peaks that have been misidentified due to retention time shifts.

This week we will begin a new multi-part discussion about calculating impurities in samples (Part 1).

Before we get into the specifics of making calculations involving impurities there is one thing I would like to address. Even though we have defined our peak names and their expected retention times in the processing method, often times our samples have impurity peaks that we did not expect to find and therefore, those peaks have no names. There is a function in the processing method which will assign names to those unknown peaks. Why would we do that? This gives us the ability to reference those peaks in custom fields and reports as well as grouping them together.

Let me show you how.

Step 1

Let’s begin by looking at a chromatogram with an active peak, some identified impurities, and a bunch of unknown impurities that have no names (Figure 1).

Empower Tips: Chromatogram with an active peak | figure 1

Figure 1

Step 2

Click the processing method tool and select the components tab (Figure 2).

Empower Tips: Processing method tool/select the components tab | figure 2

Figure 2

Step 3

Just above the table, there is a function called RT Reference Used to Name Unnamed Peaks by RRT. RRT stands for relative retention time. Simply pick a named peak from the list and any unnamed peaks will be assigned a name beginning with RRT followed by a number. That number is the retention time of the unnamed peak divided by the retention time of the selected named peak. In this case, I am going to select Active from the list (Figure 3).

Empower Tips: RT Reference Used to Name Unnamed Peaks by RRT | figure 3

Figure 3

Step 4

Return to the main window and click the quantitate tool. Now the unnamed peaks have names beginning with RRT followed by the relative retention time (Figure 4).

Empower Tips: Quantitate tool | figure 4

Figure 4

It’s that easy!

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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 #41: Calculating Impurities (Part 2)



The Fall time change is approaching. Collecting data overnight during the time change may lead to confusion when reviewing date and time stamps. Specifically, if you have a system that spans time zones that change from summer time on different dates to your server time zone.


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Categories: Empower Tips