Empower Tip: Review Window and the Processing Method

If you work in a pharmaceutical company, you follow the pharmacopeia for your methodology. There are two ways Empower can calculate signal-to-noise ratio adhering to the pharmacopeia. This tip will address calculating noise from within the chromatogram.

Bring raw data (Channels, Injections or Sample Set) into Review and open the processing method. Click the Processing Parameters tool.

Click the Suitability tab and check the box that says Calculate Suitability Results. Enter the Void Volume Time, an estimate is fine.

Select Calculate USP, EP, and JP s/n. (Deselect Use noise centered on a peak region in blank injection – that will be addressed in the next tip.)

Select where in the chromatogram you want noise calculated by clicking the Noise and Drift tab. Click Yes to the message that appears.

Select Calculate Detector Noise and Drift.

Enter a time region in the chromatogram which is free of peaks. This time region must be equal to or greater than the Segment Width and must contain at least 60 data points. The Segment Width is used for calculating average noise and drift values and it must contain at least 30 data points.

Return to the Main Window and click Integrate followed by either Calibrate or Quantitate.

USP s/n, EP s/n, and JP s/n are hidden fields by default so let’s add one to our Peaks table. Right-click on the Peaks table and select Table Properties.

On the Columns tab, find USP s/n and remove the check mark to make it visible in the table. Click OK.

The USP signal-to-noise ratio is displayed for every integrated peak.

To keep the USP s/n field in the peaks table, select Save Preferences from the File menu.

Finally, save all changes to the Processing Method.

It’s that easy!