Use of microwave-induced plasma atomic emission detection for the quantification of oxygen containing compounds

Abstract

An atomic-emission detector has been used to study the elemental response for oxygen for a series of compounds of markedly dissimilar molecular structure. Calibration curves over a range of concentrations have been generated and the variation in the slopes obtained. The slopes of these concentration versus response graphs indicate that the elemental response for oxygen varies with the molecular structure in which it is contained. Moreover, the condition of the plasma cavity discharge tube causes a variation in the slope, and hence the sensitivity of response, for the same compound. This observation may be attributed to molecular interference caused by non-instantaneous breakdown of the compounds in the plasma, resulting in incomplete, i.e., non-ideal, elemental yield. The cause of molecular interference may be a lack of thermodynamic control at either the decomposition stage or during atom recombination, e.g., the formation of CO from carbon and oxygen.