Empower Tip: Review Window and the Processing Method

This time let’s use the Update RT function in the Processing Method. The Update RT function adjusts the retention time for the peak in the calibration curve, thereby adjusting the retention time Empower uses to match unknown peaks. Sound complicated? It’s actually quite easy to use.

Let’s start by bringing a sample set into Review, in this case, there are 3 standards with 3 injections each.

Open the processing method, integrate the chromatograms for the standards and observe the retention time fluctuation for peak 1.

Open the Processing Method and select the Components tab. By default the Update RT function is set to Never which means it is turned off.

Click the down arrow to view the choices.

Which one should you pick? If the retention times for your peaks are moving in one direction with each injection (increasing or decreasing) then Replace or Replace Standards will help. If the retention times for your peaks are fluctuating around an average value then Average or Average Standards will help. Since the retention time of peak 1 is hovering around an average of 2.461 I am going to select Average Standards.

What does this do? The expected retention time for the peak is set in the components table and does not change. Every time you inject a standard Empower calculates an average retention time for the peak which can be seen in the Calibration Curve window

Even though the retention time of the peak is moving around it is identified properly for all standards. If you are interested in the math behind this please refer to your Empower Online Help or view the Empower 3 Data Acquisition and Processing Theory Guide (Chapter 4).

It’s that easy!