| Abstract: | Adaptation of available instruments to the analysis of NO2 and NH3 became important with the introduction of the Federal Constant Volume Sampling procedure for exhaust analysis in 1970. Two instruments, the NO optical detector (NOOD) and the non-dispersive infrared analyzer (ND1R), are both fast and accurate. The use of a system of two converters in conjunction with either of these instruments permits the analysis of a gas stream for NO, NO2, and NH3. NO is measured on the gas stream before conversion; NO2 is determined after the gas stream has passed over a C-Mo converter at 475°C; and NH3 is determined after the gas has been conducted over a C-Cu converter. |
