Waters Micromass ZQ 2000, Operator'S Manual

Page: 66 / 133

Setting Calibration Parameters 66
4
Parameters
Scan From, Scan To – Specifies the scan range for each calibration type.
Run Duration – Specifies how much time the instrument takes to acquire each calibration
data file.
Data Type – Specifies data type as centroid, continuum, or MCA. Waters suggests using
continuum or MCA acquisitions for electrospray calibrations.
Note: Calibrating in MCA mode limits maximum acquisition speed to 400 da/sec.
Static Span – Specifies how much of the mass scale on either side of a reference peak
the instrument scans.
Static Dwell – Specifies the time the instrument takes to scan the static span.
Slow Scan Time – Specifies how much time it takes the instrument to scan the mass
scale over the selected range when acquiring data for scanning calibrations (see next
section for details).
Fast Scan Time – Specifies how much time it takes the instrument to scan the mass
scale over the selected range when acquiring data for scan speed calibrations (see
next section for details).
Inter Scan Delay – Specifies how much time elapses between the end of one scan and
the beginning of another.
Main – Resets all parameters to their default values.
About Establishing Scan Speeds
Table 4-1 shows Waters’ recommended parameter settings for using sodium cesium
iodide as the calibrant. However, if you do not calibrate with sodium cesium iodide, you
might need to derive your own scan speed parameter values.
To determine Slow Scan Speed and Fast Scan Speed parameter values, first decide what
scan speed range to acquire your sample data within. Do this by applying the following
equation twice, once to establish the range’s lower limit and once to establish its upper
limit:
Scan speed = Scanning range / Scan time + Interscan delay
Note: These calculations use the ZQ 2000 parameter values in Table 4-1 .
Use Slow Scan Time to calculate the slowest scan speed a calibration can accommodate
(the range’s lower limit). Thus, where Slow Scan Time = 10 seconds:
Scan speed = (2040 - 50)/(10 + 0.1) = 197 amu/sec