Determination of Selenium in Polyheteroatomic Organic Compounds Using Atomic Emission Spectrometry with Microwave Plasma

A method for determining selenium as a macroelement of synthetic polyheteroatomic organic compounds using atomic emission spectrometry with microwave plasma (MP-AES) is developed. The objects of analysis are mainly various selenodiazole derivatives. Optimal conditions for sample preparation and atomic emission determination of selenium are found. To mineralize the substances under study, combustion in a flask filled with oxygen with the addition of potassium nitrate, which improves the combustion process and prevents the formation of soot, is used. Hydrochloric acid with a concentration of 0.1 M is used as an absorption solution. It is noted that before starting measurements, it is necessary to purge the monochromator and optimize the pressure in the atomic emission spectrometer nebulizer. Under the obtained conditions, the performance characteristics of the method are evaluated: the limits of detection and quantitative determination of selenium (0.2 and 0.6 mg/L, respectively), intralaboratory precision, and correctness. Using the developed method, 11 synthetic organic compounds are analyzed with a selenium content from 12 to 51%; the absolute error of the analysis does not exceed 0.3%, which meets the requirements for organic elemental analysis.