Chapter 7 Data Explorer Examples

7.1

Mariner Data Examples

 

 

 

This section includes:

 

 

 

• Improving signal-to-noise ratio

 

 

 

• Deconvoluting and evaluating unresolved

 

 

 

 

 

 

chromatographic peaks

7

 

 

• Determining if a peak is background noise

 

 

 

 

7.1.1

Improving Signal-To-Noise Ratio

 

 

 

 

 

 

 

 

Overview

Creating an extracted ion chromatogram

You can improve the signal-to-noise ratio for low-level components in the total ion chromatogram (TIC) by creating an extracted ion chromatogram for the mass of interest.

Each data point in the TIC represents the sum of all ion intensities for all masses in the corresponding spectrum. By creating an extracted ion chromatogram for a specific mass, you can screen out ion contribution from masses that you are not interested in.

The following example illustrates how you can create an extracted ion chromatogram to improve the signal-to-noise ratio for reserpine (609 Da):

1.Display the data file.

2.In the Chromatogram window, click in the toolbar, or set the Trace Replace mode to Add, if you want to add a new trace. See Section 2.4.4, Adding Traces from the Same Data File to a Window, for information.

3.From the Display menu, select Trace, then select Extracted Ion.

4.In the Extracted Ion Chromatogram window, select Center/Window, then type the mass of interest (609 Da) and the window for the mass (for example, 0.5 Da).

5.Click OK.

7-2 Applied Biosystems