Determination of the Elemental Composition of Hydrocarbon Mixtures by Gas Chromatography with Atomic Emission Detection: Increasing the Accuracy.

In this work, the accuracy of the ratio of the numbers of carbon and hydrogen atoms ( n_C/ n_H) determined in the molecules of the components of aliphatic hydrocarbon mixtures by gas chromatography with atomic emission detection (GC-AED) is studied as a function of the oxygen concentration in helium. It is shown that the highest accuracy is achieved at about 9% of oxygen, which is the highest oxygen concentration possible for the Agilent model G2350A GC-AED device. At the standard oxygen concentration (about 1.5%) recommended by the manufacturer, the accuracy of the n_C/ n_H ratios was five to ten times lower. It is shown that improving the accuracy of the n_C/ n_H ratios at the maximum oxygen concentration in plasma is followed by an increase in the detection limit approximately by an order of magnitude. [ABSTRACT FROM AUTHOR]