PerkinElmer TORION T-9, User Manual

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178 . Torion T-9 User’s Guide
The Torion T-9 instrument has approximately 4000 bins for mass data. Each mass has a width of
about 8 bins. To convert the index numbers to actual mass values it is necessary to assign a
specified mass to a specific index number. The auto calibration routine built into the instrument will
apply the calibration automatically. In addition other information is included to allow the instrument
to do an automatic check of the calibration to ensure that it was done correctly. The mass
information for each compound is stored in the Mass Item table. The data that are entered into the
table are described below.
The following are the column descriptions for the
Mass Item table.
•
Mass - This column is where the mass value to be used for calibration for a specific
compound is entered. In the example above the 174.908 mass found in bromoform has
been entered.
•
Intensity - This is the intensity of the peaks relative to the main peak. There must always
be a main peak with an intensity of 100. Usually the main peak is the largest mass peak in
the spectrum. The other intensities are a percentage of the main peak. Peak 171 has an
intensity of 41.024 percent of the main peak.
• Confidence - This value is used to set a window of the Intensity used during peak
identification and is an absolute percentage of the response of the main peak. For example
the 171 mass for bromoform has an Intensity of 41.024 and a Confidence of 40. So a
mass peak with an intensity of 1.024 to 81.024 would be in the window of acceptable
percentages for this mass peak. It would be considered detected at the right ratio to the
main peak.
•
Type
- There are three types of mass peak.
1. Main - There can only be one main mass peak for each compound and it always has an
Intensity of 100 and a Confidence value of 0.
2. Necessary - This value indicates the masses that must be present in a spectrum or the
search algorithm will not identify the peak.
3. Unnecessary - These masses are in the spectrum but are not used by the search
algorithm to identify a compound. Unnecessary masses are usually masses that are
less than 20% of the main mass. The search algorithm uses all of the masses to
determine a goodness of fit and a peak area during the library search process. That is
why even though a mass may be considered unnecessary for identification it is still
important to leave these masses in the table.