Total Volatile Organic Compounds (VOCs) is a common measurement required from industrial emissions. Commonly, a single measurement value is obtained through the use of a Flame Ionisation Detection (FID) analyser. The pyrolysis of the gas stream in a FID analyser allows it to make a measurement of the carbon content of the gas stream. FID analyser cannot indicate the relative abundances of different organic species in a gas stream and often have widely different responses for different gases. However, they are taken as the standard reference method for Total VOC emission measurements.
FTIR analysers allow for the speciation of individual organic gases in an emission stream. This means FTIR users can see the relative abundances of different types of organic species. Reporting a single Total VOC figure from FTIR data is possible by simply summing the individual organic measurements. However, this method falls down when one considers that the errors and detection limits of each individual measurement would also be summed.
Protea has developed a novel method where a single chemometric model that responds as a FID would respond is loaded into the ProtIR 204M software. This provides a single measurement of Total VOC and is shown to have good agreement with external FID analysers.