Rapid screening of polychlorinated biphenyls in sediments using non-equilibrium solid-phase microextraction and fast gas chromatography with electron-capture detection

Field Analysis of Polychlorinated Biphenyls (PCBs) in Soil Using Solid-Phase Microextraction (SPME) and a Portable Gas Chromatography-Mass Spectrometry System

An expedited field analysis method was developed for the determination of polychlorinated biphenyls (PCBs) in soil matrices using a portable gas chromatography-mass spectrometry (GC-MS) instrument. Soil samples of approximately 0.5 g were measured with a portable scale and PCBs were extracted by headspace solid-phase microextraction (SPME) with a 100 µm polydimethylsiloxane (PDMS) fiber. Two milliliters of 0.2 M potassium permanganate and 0.5 mL of 6 M sulfuric acid solution were added to the soil matrices to facilitate the extraction of PCBs. The extraction was performed for 30 min at 100 ℃ in a portable heating block that was powered by a portable generator. The portable GC-MS instrument took less than 6 min per analysis and ran off an internal battery and helium cylinder. Six commercial PCB mixtures, Aroclor 1016, 1221, 1232, 1242, 1248, 1254, and 1260, could be classified based on the GC chromatograms and mass spectra. The detection limit of this method for Aroclor 1260 in soil matrices is approximately 10 ppm, which is sufficient for guiding remediation efforts in contaminated sites. This method was applicable to the on-site analysis of PCBs with a total analysis time of 37 min per sample. However, the total analysis time could be improved to less than 7 min per sample by conducting the rate-limiting extraction step for different samples in parallel.

Extraction of ultra traces of polychlorinated biphenyls in aqueous samples using suspended liquid-phase microextraction and gas chromatography-electron capture detection

This study reports the feasibility of applying directly suspended liquid-phase microextraction (DSLPME)-gas chromatography detection for the pre-concentration and determination of low levels of eight polychlorinated biphenyls (PCBs) in aqueous samples. The technique requires minimal sample preparation, analysis time and solvent consumption and represents significant advantages over conventional analytical methods. The experimental parameters such as salt content, sample temperature, stirring rate, extraction time, micro-drop volume and breakthrough volume were investigated and found to have significant influences on DSLPME. Under the optimal experimental conditions, the enrichment factor ranged from 578 to 729, and the recovery was above 93 %. Calibration curves possessed good linearity (R(2) > 0.99) over a wide concentration range of 0.1-10.0 μg L(-1) with limits of detection ranging from 0.01 to 0.07 μg L(-1). The relative standard deviations for 1.0 μg L(-1) of PCBs in water by using internal standard were in the range 2-14 % (n = 3). The proposed simple, accurate and sensitive analytical method was applied successfully to the determination of trace amounts of PCBs in water samples.

A novel fluorinated polyaniline-based solid-phase microextraction coupled with gas chromatography for quantitative determination of polychlorinated biphenyls in water samples

Novel polyaniline (PANI) electrodeposited in the presence of fluorinated organic acid was applied as a new conductive polymer-based solid-phase microextraction (SPME) fiber candidate. Polychlorinated biphenyls (PCBs) were selected as representative compounds. Improved temperature resistance (<500 degrees C) and satisfactory extraction efficiency were obtained by introduction of fluorinated organic acid. Extraction efficiency of novel PANI for PCBs was superior to common PANI (synthesized in sulfuric acid) and polythiophene, and comparable to commercial 30 microm PDMS but with thinner stationary, i.e. 10 microm. Quantitative determination of trace PCBs in water samples was carried out using this novel SPME fiber, coupling with selective gas chromatography-microelectron capture detector (GC-microECD). The proposed method provided a linear range of approximately three orders. The detection limits were 0.05 ng L(-1) for PCB 138, 153 and 180, and 0.1 ng L(-1) for PCB 28, 52 and 101, respectively. The method was successfully applied to the analysis of spiked surface water samples with the recoveries from 83.0 to 110.7%.