Gas Phase Titration (Gpt) System - Teledyne 200A Instruction Manual

Teledyne API Model 200A NO

7.8.4 Gas Phase Titration (GPT) System

7.8.4.1 GPT Principle of Operation
Gas Phase Titration (GPT) is recommended for calibration of the M200A. Those using a NO
permeation tube should refer to TAD.
The principle of GPT is based on the rapid gas phase reaction between NO and O
produces stoichiometric quantities of NO
+ ⎯ ⎯→
NO O
3
Given that the NO concentration is known for this reaction, the resultant concentration of NO
can be determined. Ozone is added to excess NO in a dynamic calibration system as shown in
Figure 7-2, and the NO channel of the chemiluminescent analyzer detects the changes in NO
concentration. After the addition of O
calibrated NO channel is equivalent to the concentration of NO
generated may be varied by adding varying amounts of O
air used in this procedure should conform to the requirements stated in Section 7.
Dynamic calibration systems based on this principle are commercially available, or may be
assembled by the user. A recommended calibration system is described in the Federal Register
and detailed in TAD.
7.8.4.2 GPT Calibrator Check Procedure
It has been determined empirically that the NO-O
O ) if the NO concentration in the reaction chamber (ppm) multiplied by the residence time
3
(min.) of the reactants in the chamber is >2.75 ppm-min. The theory behind the development of
this equation is in the Federal Register
The following procedures and equations should be used to determine whether an existing GPT
calibration system will meet required conditions for a specific calibration.
For calibrators that have known pre-set flow rates, use equations 7-5 and 7-6 of steps 7 and 8
(below) to verify the required conditions. If the calibrator does not meet specifications, follow
the complete procedure to determine what flow modifications must be made.
Analyzer Instruction Manual, 02246, Rev. F1
X
+
NO O
2 2
2
2
as shown by the following equation:
2
, the observed decrease in NO concentration on the
3
from a stable O
3
reaction goes to completion (<1% residual
3
1 2
and in TAD.
7-16
which
3
produced. The amount of NO
2
generator. All zero
3
2
2
2
1