Research of PAH extraction conditions from bottom sediments for determination by HPLC with fluorescence detection

Abstract

Polycyclic aromatic hydrocarbons (PAH) are the most dangerous compounds that produced by the high temperature combustion of fossil fuels and biomass, domestic and industrial wastes. PAH are included to priority pollutants list due to their carcinogenic and mutagenic properties. The aim of this work was to
choose optimal extragent composition and appropriate sample mass for PAH determination in sediments. HPLC-analysis was carried out by Agilent Technologies 1260 Infinity with fluorescence detector; analytic column was ZORBAX Eclipse PAH. The necessity of solvents mixture using was shown. Solvents were acetone, hexane, methylene chloride and isooctane. Acetone was used as dehydrated agent, hexane was the main solvent for the followed analysis stages, methylene chloride was able to extract more PAH from the lipid matter and isooctane was able to prevent semivolatile components evaporation during concentrating. Recoveries were more than 50 % for low weight PAH (except naphthalene) and more than 80 % for high weight PAH. Different types of sediments (sludge and sand) were used for choosing sample mass for analysis. Several sample masses for each type of sediments were taken to estimate the optimum extraction scheme. Extracted PAH amounts were in proportion to organic matter in the composition of sediments of various types. Thus the sample mass of 2 g was considered to use for different types sediments analysis. Method detection limits ranged from 0.1 to 3.0 ng g-1 dry weight (d.w.). The applicability of the proposed method was evaluated by the PAH determination in sediments from 3 regions of River Don delta: Mertvy Donets, Perevoloka, Peschany. Sediments were collected in April, May, July and October 2016. The summary of 15 PAH concentrations in the sediments ranged from 13 to 129 ng g-1 d.w. for Peschany; from 61 to 340 ng g-1 d.w. for Perevoloka and from 176 to 299 ng g-1 d.w. for Mertvy Donets. Benzo[a]pyrene concentrations were
from 0.5 to 11 ng g-1 d.w. for Peschany; 4-31 ng g-1 d.w. for Perevoloka и 14-27 ng g-1 d.w. for Mertvy Donets. As a result of the study, a sample preparation scheme was developed, which allows determining PAH in sediments.