Thermo Scientific 42iQLS, Instruction Manual

Page: 171 / 318

Calibration
Equipment Required
Thermo Scientific 42iQLS Instruction Manual 4-5
The output manifold should be of sufficient diameter to insure an
insignificant pressure drop at the analyzer connection. The system must
have a vent designed to insure atmospheric pressure at the manifold and to
prevent ambient air from entering the manifold.
The following information describes the NO concentration standard and
the method for calculating the NO concentration standard and the NO
2
impurity.
A cylinder containing 10 to 50 ppm NO in N
2
with less than 1 ppm NO
2
is usually used as the concentration standard. The cylinder must be
traceable to a National Institute of Standards and Technology (NIST) NO
in N
2
Standard Reference Material or NO
2
Standard Reference Material.
Procedures for certifying the NO cylinder (working standard) against an
NIST traceable NO or NO
2
standard and for determining the amount of
NO
2
impurity are given in EPA Publication No. EPA-600/4-75-003,
“Technical Assistance Document for the Chemiluminescence Measurement
of Nitrogen Dioxide.”
In addition, the procedure for the certification of a NO working standard
against an NIST traceable NO standard and determination of the amount
of NO
2
impurity in the working standard is reproduced here. The cylinder
should be re-certified on a regular basis as determined by the local quality
control program.
Use the NIST traceable NO standard and the GPT calibration procedure
to calibrate the NO, NO
2
, and NO
x
responses of the instrument. Also
determine the converter efficiency of the analyzer. Refer to the calibration
procedure in this manual and in the Code of Federal Regulations, Title 40,
Part 50, Appendix F for exact details. Ignore the recommended zero offset
adjustments.
Use the following procedure to calculate the NO concentration standard
and NO
2
impurity.
1. Generate several NO concentrations by dilution of the NO working
standard.
2. Use the nominal NO concentration, [NO]
NOM
, to calculate the diluted
concentrations.
Output Manifold
Reagents
NO Concentration Standard
Assaying a Working NO Standard
Against a NIST-traceable NO
Standard