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Model 9110T NOx Analyzer EPA Protocol Calibration
Teledyne Analytical Instruments 235
To establish traceability, data must be obtained routinely by repeated measurements of standard
reference samples (primary, secondary, and/or working standards). More specifically, working
calibration standards must be traceable to standards of higher accuracy.
10.9.1.1. Certification Procedures of Working Standards
This procedure requires the use of calibrated NO gas traceable to an NIST-SRM SRM and the gas phase
titration calibration procedure (Section 10.5) to calibrate the NO, NO
X
, and NO
2
responses of the
analyzer. Also the efficiency of the analyzer’s NO
2
converter must be determined (Section 9.1.4).
Generate several NO concentrations by diluting the NO working standard. Use the nominal NO cylinder
concentration, [NO]
NOM
, to calculate the diluted concentrations. Plot the analyzer NO response (in ppm)
versus the nominal diluted NO concentration and determine the slope, S
NOM
. Calculate the NO
concentration of the working standard [NO]
STD
from:
Equation 10-11
[NO]
STD
= [NO]
NOM
x S
NOM
A more detailed procedure is presented in Reference 1 (Section 10.10).
10.9.1.2. Other Methods of Establishing Traceability
Methods of establishing traceability are:
Using a NO working standard traced to NIST NO
2
standard.
Using a NO
2
working standard traced to NIST NO
2
standard.
Using a NO
2
working standard traced to NIST NO standard.
IMPORTANT
IMPACT ON READINGS OR DATA
If the NO
2
impurity in the NO cylinder, [NO
2
]
imp
is greater than the 1 ppm
value allowed in the calibration procedure, check that the NO delivery
system is not the source of contamination before discarding the NO
standard.
For further information on calibration by GPT and NO
2
permeation
devices, refer to part 50 of Section 1, Title 40 CFR, Appendix F Reference
13 of that Appendix.
10.10. REFERENCES
1. Environmental Protection Agency, Title 40, Code of Federal Regulations, Part 50, Appendix F,
Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the
Atmosphere (Gas Phase Chemiluminescence), Federal Register, 41 (232), 52688-52692, December
1976 (as amended at 48 FR 2529, Jan 20, 1983).
2. Ellis, Elizabeth C. Technical Assistance Document for the Chemiluminescence Measurement of Nitrogen
Dioxide, U.S. Environmental Protection Agency, Research Triangle Park, NC. 83 pages, December
1975. Available online at http://www.epa.gov/ttn/amtic/files/ambient/criteria/reldocs/4-75-003.pdf.
3. Environmental Protection Agency, Title 40, Code of Federal Regulations, Part 58, Appendix A,
Measurement Principle and Calibration Procedure for the Measurement of Nitrogen Dioxide in the