You can acquire and display mass spectral data (intensity versus m/z) as one of two data types:
Data Type | Description |
|---|---|
Profile | With profile data, you can see the inherent shape of the peaks in the mass spectrum. The mass spectrum divides each atomic mass unit into several sampling intervals. The intensity of the ion current is determined at each sampling interval. The intensity at each sampling interval is displayed with the intensities connected by a continuous line. Profile data is a good way to see the isotopic distribution, especially for higher charged ions. NOTE Profile data is not recommended for large scale studies because it generates files that are much larger in size (approximately 5 times more) than centroid data. |
Centroid | With centroid data, you can see the mass spectrum as a bar graph. This scan data type sums the intensities of each set of sampling intervals. This sum is displayed versus the integral center of mass of the many sampling intervals. An advantage of centroid data is that it requires about one-tenth the computer disk space of what is required for profile data. However, with centroid data, you lose information about the fine isotope features and the linearity of the ion signal. |
The following figures shows examples of the profile and centroid data types.