Chapter 5 Examining Spectrum Data

6.Specify reference masses to add by doing either of the following:

•Click a mass, then click OK.

•Type new reference mass information in the Name, Theoretical m/z, Charge, and Elemental Composition fields, then click OK.

NOTE: You must type a minus sign (–) preceding the charge in the Charge text box for negative charge states.

NOTE: You can save changes to the Calibration Reference File by clicking Save. For more information, see “Modifying a calibration reference file” on page 5-20.

The Automatic Calibration Settings dialog box is displayed again (see Figure 5-7 on page 5-30).

7.

Repeat step 5 and step 6 to add all needed masses.

8.

To delete masses, do either of the following:

 

 

• Select a reference, then click Delete Selected

 

 

Reference

 

 

• Click Delete All References

9.

Enter Reference Matching Criteria:

 

 

• Minimum Intensity— Peaks must be above this

 

 

intensity to be considered a match. Select the unit

5

 

for Minimum Intensity, % Relative Intensity or

 

Absolute Counts.

 

 

 

 

• Mass Tolerance— Peaks must be within this

 

 

tolerance of the theoretical m/z to be considered a

 

 

match. Select the unit, m/z or ppm.

5-32 Applied Biosystems