Technical data

116 Agilent 6200 Series TOF and 6500 Series Q-TOF LC/MS System Concepts Guide
4 Data Acquisition
Estimate of worklist file size
given mass range using a typical mass calibration curve. The
Agilent 6540 UHD Accurate-Mass Q-TOF has approximately 25%
more data points.
Note that low masses require more
data points than high masses
because of the non-linear nature of
the time to mass conversion.
Each data point stored requires 12 bytes of storage. A mass
range of 250 to 3000 requires 840,000 bytes per spectrum at 1
GHz acquisition rate. If the scans/sec. equal 1, then the data
storage required for one minute worth of spectra before
compression is 50,400,000 bytes or about 48 MB. Then, this data
is compressed which means the actual data storage needed is
between 2.4 MB and 16 MB (with a compression ratio between 3
and 20).
If the run time on a run with one time segment is 5 minutes,
then one run requires between 12 MB and 80 MB of disk space.
A worklist with 10 samples using the same mass range requires
between 120 and 800 MB of disk space. If the scan rate is set to
20 scans per second, the data file could require a large amount
of disk space.
Spectrum metadata In addition to data points, information on
the spectrum, such as the instrument actuals and set points,
used during acquisition is stored with each spectrum. This
information takes 2884 bytes per spectrum or about 8.2 MB for
the worklist described above.
Table 13 Number of data points pre spectrum for given mass ranges
Mass range
(Daltons)
Number of data
points (1 GHz)
Number of data
points (2 GHz)
Number of data
points (4 GHz)
50 to 750 50,000 100,000 200,000
50 to 1000 60,000 120,000 240,000
50 to 3000 100,000 200,000 400,000
250 to 1000 30,000 60,000 120,000
500 to 3000 60,000 120,000 240,000
250 to 3000 70,000 140,000 280,000