Известия Томского политехнического университета: Инжиниринг георесурсов (Nov 2017)
Determination of alkanes and alkylbenzenes in water samples using solid-phase microextraction and following gas-liquid chromatographic analysis
Abstract
Relevance of the research is caused by the need to improve the efficiency of sample preparation methods for determining trace amounts of hydrocarbons (alkanes and alkyl benzenes) in aqueous solutions. The aim of the work is to determine regularities of separation of alkanes and alkylbenzenes from water samples using solid-phase microextraction and testing the proposed methods. Methods of analysis: gas chromatography, gas chromatography-mass spectrometry. Results. Hydrocarbons in water samples are identified via solid phase microextraction and centrifugation. The sample preparation technique involves the use of special cartridge for adsorption of substances from water with 2 mg of sorbent. The hydrocarbons are extracted from the sorbent with 5-10 μl of solvent using a centrifuge. In order to extract hydrocarbons (alkanes and alkylbenzenes) various types of sorbents (Porapak Q, Tenax TA, and C18 sorbent from Supelco Co.) and solvents (methanol, acetone, and carbon tetrachloride) are used. Using Tenax TA with acetone and Porapak Q with carbon tetrachloride is optimal for microextraction. The influence of sorbent mass and solvent volume on extraction of substances and the intensity of analytical signal is shown. Increase of sorbent mass from 2 to 10 mg leads to lowering the intensity of analytic signal. The model solutions were used for determining the limit of substance detection for gas chromatography (0,3 mkg/l at a signal-to-noise ratio of 3). The method was tested on the example of analysis of aqueous solution containing components of synthetic liquid fuel, obtained by dimerization of propane-butane mixture with water in a plasma chemical reactor.
