Improving the accuracy of carbon-to-hydrogen ratio determination for P, N, S, O, Cl, and Br-containing organic compounds using atomic emission detection

The objective of this work was to investigate the dependence of atomic emission detector C and H response on microwave-induced plasma conditions and to improve the accuracy of carbon-to-hydrogen ratio determination for trialkylphosphates, herbicides, chlorophenols, and sulfur-containing organic compounds. Compounds which differed structurally from the analytes were used as reference compounds. It was found that when the oxygen concentration in the helium was the maximum for the instrument (9%) relative errors in carbon-to-hydrogen ratio determination were 3-8%, irrespective of analyte and reference compound structure, whereas when working in the mode of operation recommended by the manufacturer of the instrument (1.5% oxygen in helium) the respective errors were 10-20% or higher. This improvement in the accuracy of carbon-to-hydrogen ratio determination was accompanied by a factor of ten decrease in sensitivity.