Identification of impurities in high-purity sulfur using gas chromatography-mass spectrometry method

Abstract

For the first time the molecular impurity composition of high-purity sulfur was investigated using gas chromatography-mass spectrometry method. The sample preparation consisted of extracting the impurities from the sulfur samples during their vacuum distillation. The sample mass of sulfur, which was used for the extraction, was up to 1 kg. Impurities were condensed in glass ampoules which then carried them to the inlet in the dosing system of gas chromatography-mass spectrometer. For their separation, GS-GasPro capillary adsorption columns with a modified silica gel sorbent and with polytrimethylsilylpropyne were used. The joint application of these columns made it possible to determine a wide range of impurity substances in sulfur. Identification of impurities was carried out by comparing their experimental mass spectra with the data from the NIST database. In the case of overlapping chromatographic peaks of impurities their identification was carried out according to the characteristic ions and subtracting the peaks of ions that belong to the adjacent component. It was found that, when using the column with polytrimethylsilylpropyne, oxygen and nitrogen containing organic substances elute in asymmetric peaks with a steep front and a diffused rear. In high purity sulfur the impurities of permanent gases, carbon dioxide, hydrogen sulfide, sulfur dioxide, сarbonyl sulphide, saturated and unsaturated hydrocarbons C 2 -C 8 , aromatic hydrocarbons, oxygen-, nitrogen-, sulfur-containing hydrocarbons were identified. The total number of identified impurities equaled to 51. Keywords : high-purity sulfur, impurities, identification, gas chromatography-mass spectrometry, capillary column DOI: http://dx.doi.org/10.15826/analitika.2017.21.3.005 А .Iu. Sozin, M.F. Churbanov, О .Iu. Chernova, T.G. Sorochkina, I.V. Skripachev, G.E. Snopatin G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Science, Tropinina Str., 49, Nizhny Novgood, 603950, Russian Federation