User`s guide

Chapter 7 PSD Analysis
7-22 PerSeptive Biosystems
7
Hint: You can use the Windows calculator to determine
natural log values. If the ln function is not displayed when
you open the Windows calculator, select Scientific from the
View menu in the calculator to access advanced functions.
Hint: The Angiotensin_PSD.BIC file provided includes
10 segments, which is suitable for many applications. If the
mass you are analyzing differs by more than 300 Da from
the mass in the Angiotensin_PSD.BIC file (1296 Da), you
may need to acquire more or fewer than 10 segments to
observe the fragment ions of interest.
Decrement ratio The software can automatically calculate the Mirror Ratio
settings needed for each segment. To do so, it uses a Mirror
Ratio setting of 1.000 and a Decrement Ratio parameter that
you enter.
The correlation between the Mirror Ratio and the Decrement
Ratio is the inverse percentage. That is, if you want to obtain
20% segments, set the Decrement Ratio to 0.8000. If you
want to obtain 80% segments, set the Decrement Ratio to
0.2000.
Default Mirror
Ratio settings
The default Mirror Ratio is 1.0000. The default Decrement
Ratio is 0.7500. Therefore, the default Mirror Ratios yield the
following 25% segments:
Increase the Decrement Ratio to collect smaller segments.
Decrease the Decrement Ratio to collect larger segments.
1.000 0.237
0.750 0.178
0.563 0.133
0.422 0.100
0.316 0.075