A Comparative Study of Procedures for Preparing Samples of Bottom Sediments in the Determination of Petroleum Products by Chromatographic Methods

Resumo

A method for determining aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments using gas chromatography–mass spectrometry and HPLC with spectrofluorimetric detection, respectively, was developed. Various methods are studied for extracting PAHs from the matrix of a solid sample: extraction with organic solvents under mechanical stirring, ultrasonic treatment, and in a Soxhlet apparatus. The recovery depends on the method of sample treatment; it is maximum at mechanical stirring and extraction in the Soxhlet apparatus (up to 60–80%). The simplest method including mechanical stirring is optimal. A procedure for the quantitative separation of aliphatic hydrocarbons and PAHs in a wide concentration range is proposed using column chromatography on silica gel. The limits of detection for PAHs were 0.1–3 ng dry weight; RSD = 4% for benzo[a]pyrene at a concentration of 1 ng/g dry weight. The developed procedure was used to determine aliphatic hydrocarbons and PAHs in real samples of bottom sediments. The proposed option of sample preparation enables identifying and quantifying two groups of substances of petroleum components from one sample and thereby expands the possibilities of determining the source of hydrocarbon contamination of a water body.