Which instrumental analysers can be used to determine the concentrations of oxides of nitrogen?
Approved method USEPA Method 7E requires a sample to be continuously extracted from the gaseous stream. A fraction of the sampled stream is conveyed to an instrumental analyser for determination of the concentrations of nitric oxide (NO) and oxides of nitrogen (NOx). The method nominates use of a chemiluminescence analyser. However, as noted under TM-11 of AMSAAP, the EPA recognises the use of any appropriate instrumental analyser for determination of NO and NOx concentrations, provided the performance specifications of USEPA Method 7E are met to ensure reliable data. The instrumental analyser must also measure both NO and NOx directly.
