Total Carbon Organic versus Graphitic Elemental

The separate determination of organic and elemental carbon in atmospheric particles has been addressed in a number of ways by many workers over a period of 

Four major methods have been used to separate the organic elemental carbon thermal methods, digestion, extraction, and optical techniques. These are discussed in detail in the volume on particulate carbon edited by Wolff and Klimisch (1982) and in the article by Cadle et al. (1983). 

In the thermal methods, the sample is heated to increasingly higher temperatures, with most steps being carried out in the presence of 02. The basis of this method is that volatile organics will vaporize first and then other organic compounds will be oxidized. Only at the highest temperatures will graphitic carbon oxidize. The carbon thus ejected into the vapor phase at various temperatures is detected in the form of C02 or, alternatively, after catalytic reduction, as CH4. 

FIGURE 11.67 Schematic diagram of one type of thermal analyzer for organic and graphite carbon (adapted from Huntzicker et al., 1982). 

As might be expected for a measurement based on simple light absorption in a complex sample, there are 

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