Teledyne API Model 200AH NO
X
Analyzer Instruction Manual, 06492, Rev. G2
7-15
NOTE
It is important to note that if you are using blended calibration gasses,
other components of the blend can interfere with the NO concentration
value. This can affect calibration accuracy and linearity. See
Section 9.2.10 for additional details.
Zero Air:
Ultra Zero Grade Air, 99.999% pure
Nitrogen:
Ultra High purity Nitrogen, 99.999% pure
7.12.2. Calibration Frequency
Typically, the data acquisition system will perform a daily calibration. This consists of switching
valves to have calibration gas introduced at the sample probe and passing through the entire
sample induction system. The instrument or data acquisition system’s slope and offset will be
adjusted to produce the correct response of the system.
Once per quarter, the M200AH should be calibrated using one of the procedures in Section 7.
Also a 3 point linearity check (zero, low span, high span) will be performed to confirm system
linearity.
It is important to note that when doing a linearity check, the calibration gasses have analysis
errors. For example if 2% standards are being used, the linearity could be theoretically be as
much as 4% in error, even if the instrument and sample induction system are “perfect”. Teledyne
API recommends that EPA Protocol 1 ( 1%) gasses be used for linearity checks to minimize
non-linear responses due to analysis errors of the gas bottles.
7.12.3. Converter Efficiency
In many applications the NO
2
concentration is low enough (<5%) that converter efficiency
checks are not required. If your application requires an efficiency check, refer to 40 CFR, Part 60
Method 7E for the recommended procedure. Refer to Section 7.11 if automatic converter
efficiency compensation is required.
