Determination of Nitrogen Oxides of Low Concentration in Exhaust Gas by Improved Phenol Disulfonic Acid Method
1978 Volume 64 Issue 2 Pages 297-302
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1978 Volume 64 Issue 2 Pages 297-302
There is in Japanese Industrial Standard the method for determination of nitrogen oxides (NOx), JIS K 0104 in which the mesuring range of phenol disulfonic acid method (PDS method) is described to be between 10 and 2000ppm. However, it is known that this method shows considerably lower values in the range of low concentration of NOx and requires very long time for analysis.
Therefore, the authors devised a gas sampling apparatus in which NO was oxidized with oxdizing gas to remove these weak points. Two methods, the oxidation method with oxygen and oxidation method with ozone, for the determination of NOx have been experimented.
The following results were obtained.
(1) Analytical results of NO balanced with nitrogen by this method agreed closely with those by chemiluminescent method (NOx meter) and standard deviation for 10ppm NO and 50ppm NO were 0.126 and 0.293 respectively.
(2) The time required for analysis was shortened from 1/5 to 1/7 by the use of this method.
