Application of dynamic headspace and gas chromatography coupled to mass spectrometry (DHS-GC-MS) for the determination of oxygenated volatile organic compounds in refinery effluents

The paper presents a new procedure for the determination of oxygenated volatile organic compounds (O-VOCs) in postoxidative effluents from the production of petroleum asphalt using dynamic headspace coupled to gas chromatograph-mass spectrometry in the selected ion monitoring (SIM) mode (DHS-GC-MS). Among the GC capillary columns tested, a polar SLB-IL111 column with the ionic liquid stationary phase was found to be superior due to its high selectivity for n-alkanes and individual oxygenated volatile organic compounds. The low detection limit, good reproducibility and a wide linear range allows determination of O-VOCs at low concentration levels and applicability of the procedure to routine analyses of O-VOCs in industrial effluents with a very complex composition. The developed procedure was used for the analysis of real samples – raw effluents from the production of bitumens and effluents treated chemically through oxidation. Thirteen compounds at concentrations ranging from 0.01 µg/mL do 118.61 µg/mL were identified in the effluents. In addition, nine more compounds, mostly alcohols, aldehydes and ketones, were identified using the SCAN mode. The paper demonstrated the need for monitoring O-VOCs in processes of chemical treatment of effluents. Due to pathways of oxidation of organic pollutants present in effluents, O-VOCs become secondary pollutants. A substantial increase in concentration of some groups of compounds, i.e. phenol and its derivatives and aliphatic and cyclic alcohols, was found in oxidized effluents. The presence of these compounds has a negative effect on the activated sludge used in refinery wastewater treatment plants