What is the sampling rate of the acquisition unit? How is this related to scan speed?
The sampling rate of the analog acquisition unit is 33 kHz … this can be parsed out in many ways during a scan. Scan speed (in terms of amu/sec) is developed by parsing these samples across the acquired mass range. For example, the first parameter that must be specified is how many sample points are needed to characterize a mass spectral ion peak. On a quadrupole instrument (with unit resolution), the peaks are usually one amu wide, and typically 8 points are needed per peak in order to characterize it well enough for a peak detector to consistently determine peak centroid value and position. So on a 1000 amu scan, 8000 points (8 points per amu x 1000 amu) would be needed. At the 33 kHz rate, this would allow the scan to be completed in about 0.25 seconds … so a rate of 4000 amu/sec would be possible based on our electronics. However, in most instruments, this rate is not achievable based on the mass filter electronics within the spectrometer. In these cases, the speed can be “slow
