Thermo Scientific 42iQLS, Instruction Manual

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Calibration
Calibration
Thermo Scientific 42iQLS Instruction Manual 4-15
11. Record the NO
2
concentration and the analyzer's NO
2
response.
12. Maintaining the same F
NO
, F
O
, and F
D
, adjust the ozone generator to
obtain several other concentrations of NO
2
over the NO
2
range (at least
five evenly spaced points across the remaining scale are suggested).
13. Record the stable responses and plot the analyzer's NO
2
responses
versus the corresponding calculated (using the above equation for
[NO
2
]
OUT
) concentrations and draw or calculate the NO
2
calibration
curve.
Note It is important that the curve be linear within

1% FS over the NO
2
range. If the curve is nonlinear, the analyzer is not operating correctly,
(possible leak, or converter failure, etc.), and should be serviced. Assuming
the curve is linear, subsequent data should be reduced using this NO
2
calibration curve response.
▲
Note The user can also manually change the calibration factors. This is
often useful in a troubleshooting situation. From the Home screen, choose
Calibration>Advanced Calibration>Manual Calibration>
Adjust Span
Coefficients .
However, after the above calibration procedure is completed, all subsequent
data reduction depends on the calibration parameters remaining the same
as during the initial calibration. Therefore, never change any calibration
factor without first recording the value so that after any troubleshooting
procedure is completed, the initial value can be re-entered thereby not
altering the multipoint calibration.
▲
Although it is recommended that a GPT system be used to calibrate the
analyzer, the procedure described in the Code of Federal Regulations, Title
40, Part 50, Appendix F using a NO
2
permeation tube may be used as an
alternative procedure for calibrating the instrument.
Alternative Calibration
Procedure Using NO
2
Permeation Tube