In this tip we are going to learn why smoothing the chromatogram can be helpful (Part 7). If the baseline is noisy you can use a small amount of smoothing to improve the baseline and the signal-to-noise ratio. Please note: Be careful, smoothing algorithms smooths all data points, not just baseline points. If you apply too high of a smoothing factor you can smooth away your peaks.
STEP 1 We start without any smoothing and see the peak of interest has a signal-to-noise ratio of 29:1.
There is more information if you go to the Results window within Review. We see the height, signal-to-noise ratio, and the peak-to-peak noise which is 33659.
Now we apply a small amount of smoothing using the Smoothing/Offset tab in the Processing Method.
The signal-to-noise ratio for our peak of interest is now 42:1.
Returning to the Results window, we see a slight reduction in peak height and a significant reduction in the peak-to-peak noise to 22715.
It’s that easy!
Here’s a Question: In Tip 47, we covered deriving a channel and applying a smoothing factor to the Derived Channel. Is there an advantage to smoothing via the Processing Method or via a Derived Channel? Stay tuned in, I will provide the answer in next week’s tip.
Savitzky-Golay smoothing averages data points. For more detailed information, check out the book called Chromatographic Integration Methods by Norman Allen Dyson. There is a good section on filtering and smoothing chromatographic signals.
This procedure can be followed using the QuickStart or Pro interface.
Besoin d’aide ? Contactez un spécialiste Waters.