High Extraction Efficiency for POPs in Real Contaminated Soil Samples Using Accelerated Solvent Extraction

Abstract

Systematic investigations were performed to study the dependence of the extraction efficiency of persistent organic pollutants (POPs), including chlorobenzenes, HCH isomers, DDX, PCB congeners, and PAHs, on the accelerated solvent extraction (ASE) operating variables solvent and temperature. Mixed soil samples from two locations with considerable differences in soil properties and contamination in the Leipzig-Halle region (Germany) were used. The objective was to optimize ASE for the extraction of POPs from real soil samples and to improve on the results achieved with Soxhlet extraction (SOX). Solvents with differing polarities were tested. Quadruple and triple determinations were performed on the two soils, respectively, between 20 and 180 degrees C in 20 degrees C steps. All the results were compared with those obtained by SOX, as well as, in some cases during preliminary studies, by ultrasonic extraction (USE). In ASE, the optimum conditions proved to be two extraction steps at 80 and 140 degrees C (average RSD 10.7%) with three static cycles (extraction time 35 min) using toluene as solvent and at a pressure of 15 MPa. Owing to the superior analyte/matrix separation by ASE, in many cases for real soil samples analytical values better by up to 1 order of magnitude or even more were obtained compared to SOX results.

Advantage of solvothermal procedure for polychlorinated biphenyls removal from e-waste contaminated site

“…4 shows that PCBs removal efficiency was not obvious at lower temperatures (90-110 • C), and it continuously increased till around 150 • C, but declined at higher temperature 170 • C for congeners of PCB66, PCB118, PCB153, PCB138, PCB180 and PCB170. This implied that desorption of PCBs from sample matrix controls the removal efficiency [39] and certain intermolecular bonds between PCBs and soil matrix can only be broken at higher temperatures and pressures, and this is probably the decisive advantage of solvothermal procedure as compared to Soxhlet or elution [40]. However, certain temperature range (>150 • C) may limit the removal efficiency, as also demonstrated by Hubert et al [40].…”

“…This implied that desorption of PCBs from sample matrix controls the removal efficiency [39] and certain intermolecular bonds between PCBs and soil matrix can only be broken at higher temperatures and pressures, and this is probably the decisive advantage of solvothermal procedure as compared to Soxhlet or elution [40]. However, certain temperature range (>150 • C) may limit the removal efficiency, as also demonstrated by Hubert et al [40]. In contrast, concentrations of PCB8, PCB18, PCB28 and PCB44 kept increase from 90 • C to 170 • C. The difference in optimal temperatures for PCB congeners was ascribed to the different chlorination degree of PCB congeners as discussed by Björklund et al [20].…”

A gradual advancement of the extraction and cleanup techniques for residue analysis of pesticides in food matrices and liquid products: a review

“…It allows the universal use of solvents or solvent mixtures with different polarities and individually variable pressures of 5-200 atm (0.3-20 MPa) in order to maintain the extraction solvent in a liquid state, and temperatures ranging from room temperature up to 200°C in order to accelerate extraction. The solvent volume can be reduced because the solubility increases 74 . The use of ASE in the analysis of residual pesticides in food has been reported by a few researchers.…”

Sequential ASE extraction of alkylphenols from sediments: Occurrence and environmental implications

“…It was reported that nonextracted atrazine, isoproturon, and dicamba residues in several soils could be absorbed to earthworm tissues [34]. It was also found that a considerable fraction of nonextractable PAH residues in a soil could be mineralized under different ecological stress conditions [35]. Although many investigators now pursue less aggressive extraction techniques to approximate or mimic bioavailability, how the different extraction methods are related to the bioavailability of APs in the sediments is our future research goal.…”

“…Some studies have made a comparison between ASE and Soxhlet extraction and found that the performance of ASE was consistently equivalent to or better than Soxhlet extraction [35,36]. The ASE (Dionex 300, USA) is an automated system for extracting organic compounds from a variety of solid samples.…”