Levels and patterns of polychlorinated biphenyls (PCBs) were studied in surface soil samples collected in the coastal part of Croatia within and surrounding four different airports and in the vicinity of two partially devastated electrical transformer stations. The compounds accumulated from air-dried soil samples by multiple ultrasonic extraction with an n-hexane?:?acetone 1?:?1 mixture were analysed by capillary gas chromatography with electron capture and ion-trap detection. PCBs were quantified against a standard Aroclor 1242/Aroclor 1260 mixture and a standard mixture of 17 individual PCB congeners (IUPAC No.: 28, 52, 60, 74, 101, 105, 114, 118, 123, 138, 153, 156, 157, 167, 170, 180, and 189). The mass fractions of total PCBs in 18 soil samples collected within the airport premises ranged from 3 to 41?327?µg/kg dry weight (dw) (median: 533?µg/kg?dw), and those in 21 samples collected at a distance ranging from several metres to 5?km away from the airport fence, from <1 to 39?µg/kg?dw (median: 5?µg/kg?dw). The highest PCB levels were determined in soils along the airport aprons where the aircrafts were serviced and refuelled. The PCB pattern was very similar to technical Aroclor 1260 in all airport soils. The PCB pattern in 22 soils collected in the vicinity of electrical transformer stations was dominated by congeners contained in Aroclor 1242. These soils contained 7 to >400?µg/kg?dw of total PCBs. One highly PCB-contaminated airport soil sample was analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). With an international toxic equivalent (I-TEQ) of 9.7?ng/kg?dw, the airport soil contamination was within values typical for urban and rural areas, and the congener patterns gave no clear indication for PCBs as the only source of PCDDs/PCDFs. 相似文献
We compared two extraction methods for use in GC-ECD determination of polychlorinated bi- and terphenyl contaminants (PCBs and PCTs respectively) in mussels (Mytilus galloprovincialis). Mussels spiked with standard PCB and PCT mixtures Aroclor 1260 and Aroclor 5460 were extracted with cold acetonitrile, or with 1:1 n-hexane/ dichloromethane in a Soxhlet extractor, which gave the better mean recoveries of 99.0 +/- 2.5% and 59.5 +/- 8.3% for PCBs and PCTs respectively. 相似文献
A procedure focused on microwave-assisted extraction in open vessel (MAE-OV) and gas chromatography with electron capture detection (GC-ECD) was used for the determination of 26 congeners of polychlorinated biphenyls (PCBs) in soil samples. The limit of detection (LOD) and limit of quantification (LOQ) were evaluated for commercial PCBs mixture Aroclor1260. LOD and LOQ were calculated for each PCB congener, in the ranges (0.03–0.27?ng?g?1) and (0.11–0.70?ng?g?1), respectively. After optimization, 26 PCBs congeners were successfully extracted from soil samples with recovery amounts ranging between 84.7% and 117.3% for all PCBs congeners. The evaluated method of MAE-OV showed good separation and extraction of all PCBs congeners from soil samples. Extraction parameters such as solvent choice, power and extraction time were investigated. This study indicated that MAE-OV could be an interesting alternative method to extract PCBs from soils, since it is economical, easy, fast and requires low amounts of solvents. 相似文献
Summary Gas chromatography of polychlorinated biphenyls and chlorinated pesticides in water samples has been performed after adsorption
from a 50–250 mL sample on to a cartridge containing 100 mg cyanopropyl-bonded porous silica. The PCBs are desorbed with 500
μL ethyl acetate, which is concentrated and analysed by gas chromatography with electron-capture detection (GC-ECD).
The average recovery of 1 ppb PCB congeners at from distilled water and from Marta river water is ≥95% (standard deviation
≤2.5). The average recovery of 20 ppb Aroclor 1260 from Marta river water was ≥91% (standard deviation ≤3.5).
In the separation of the PCBs from the chlorinated pesticides only aldrin, heptachlor and 4,4′-DDD are adsorbed with the PCBs
by the CN Sep-Pak cartridge. The method proposed is rapid, simple and reproducible. 相似文献
A rapid and uncomplicated method for the fractionation of PCBs leading to an isolation of the highly toxic non-ortho substituted
PCBs is described. The liquid chromatographic separation was achieved on a stationary phase consisting of activated carbon
and Celite 545. Using eluents with different polarity, isolation of the non-ortho substituted PCBs in a single fraction was
achieved. The fractions were analysed by GC/MS. The method was tested by the determination of non-ortho substituted PCBs in
technical mixtures (Aroclor 1254 and Aroclor 1242). The results were compared with those obtained by using an HPLC fractionation
on a porous graphitic carbon column. Finally, the micro-column fractionation was used for the determination of non-ortho substituted
PCBs in native soil samples.
Received: 5 March 1997 / Revised: 4 June 1997 / Accepted: 6 June 1997 相似文献
Summary Gas chromatography of polychlorinated biphenyls and chlorinated pesticides in water samples has been performed after adsorption
from a 20–200-mL sample on to a cartridge containing 100 mg diol-bonded porous silica. The PCBs are desorbed with 500 μL ethyl
acetate, which is concentrated and analysed by gas chromatography with electron-capture detection (GC-ECD).
The average recovery of 0.1 ng mL−1 PCB congeners from distilled water and from Aniene river water is≥95% (standard deviation≤2.8). Average recoveries of 25
ng mL−1 Aroclor 1254 from distilled water and from Aniene river water were, respectively, 94.4% and 92.5% (standard deviation 5.8).
In the separation of PCB congeners from the chlorinated pesticides only the aldrin (40%) was eluted with the PCBs from the
diol Sep-Pak cartridge by aqueous methanol. The method described is simple and reproducible. 相似文献
A rapid and uncomplicated method for the fractionation of PCBs leading to an isolation of the highly toxic non-ortho substituted PCBs is described. The liquid chromatographic separation was achieved on a stationary phase consisting of activated carbon and Celite 545. Using eluents with different polarity, isolation of the non-ortho substituted PCBs in a single fraction was achieved. The fractions were analysed by GC/MS. The method was tested by the determination of non-ortho substituted PCBs in technical mixtures (Aroclor 1254 and Aroclor 1242). The results were compared with those obtained by using an HPLC fractionation on a porous graphitic carbon column. Finally, the micro-column fractionation was used for the determination of non-ortho substituted PCBs in native soil samples. 相似文献
The analysis of persistent organic pollutants is a real challenge due to the large number of compounds with varying chemical
and physical properties. Gas chromatography with electron capture detection or mass spectrometry has been the method of choice
for the past 50 years. Comprehensive two-dimensional gas chromatography (GCxGC) coupled with micro-electron capture detector
(μECD) is a new method that can analyze polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs) and chlorobenzenes
(CBz) in a single analytical run with enhanced selectivity and sensitivity over single column methods and can also be used
to screen for other halogenated organics in environmental samples. An accredited routine method using commercially available
LECO GCxGC-μECD and a column combination DB-1 × Rtx-PCB has been developed to analyse PCBs/OCs/CBz in soils, sediments and
sludges. The method provides quantification of Aroclors and Aroclor mixtures to within 15% of target values and sub-nanogrammes
per gramme detection limits. 相似文献
The gas chromatographic separation of PCB 138, PCB 163, and PCB 164 in Aroclor mixtures can be achieved by application of a CP-Select for PCBs stationary phase. In technical PCB mixtures with a degree of chlorination exceeding 40% (Aroclor 1242, 1254, 1260, and 1262) these three hexa-chlorobiphenyls were present. The highest concentrations of the PCBs under investigation were found in Aroclor 1260. The ratio PCB 163: PCB 138 increased with an increasing degree of chlorination of technical PCB mixtures. 相似文献
A robust analytical method is presented for the direct determination of polychlorinated biphenyls in soil samples by thermal desorption/gas chromatography/mass spectrometry. The method is simple to perform (thermal desorption and analysis are performed in-line employing a limited amount of sample, 2?mg) and eliminates the need for any solvent and time-consuming extraction. The analytical procedure was optimized using a soil sample spiked with Aroclor 1254 and Aroclor 1260 and validated with a certified industrial soil sample for which the concentration of thirteen PCB congeners are known. Limits of detection were sensitive to matrix effects and varied substantially among analytes. The matrix effect resulted in a reduction of the limits of detection by 1.5–10 times. However, it was found that the matrix effect is not due to ion suppression but to the increase of the noise of selected ion monitoring (SIM) traces, indicating that no limitation exists with using a single surrogate standard. By employing a 13C-labelled PCB internal standard, limits of detection in the range of 0.8 to 10?µg?g?1 of soil were obtained. The obtained experimental results demonstrated that the proposed analytical method can be conveniently applied for screening a large number of heavily contaminated soil samples thus avoiding the employment of harmful solvents and time-consuming extraction procedures. 相似文献
The orthogonality of three columns coupled in two series was studied for the congener specific comprehensive two-dimensional GC separation of polychlorinated biphenyls (PCBs). A non-polar capillary column coated with poly(5%-phenyl–95%-methyl)siloxane was used as the first (1D) column in both series. A polar capillary column coated with 70% cyanopropyl-polysilphenylene-siloxane or a capillary column coated with the ionic liquid 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethane-sulfonyl)imide were used as the second (2D) columns. Nine multi-congener standard PCB solutions containing subsets of all native 209 PCBs, a mixture of 209 PCBs as well as Aroclor 1242 and 1260 formulations were used to study the orthogonality of both column series. Retention times of the corresponding PCB congeners on 1D and 2D columns were used to construct retention time dependences (apex plots) for assessing orthogonality of both columns coupled in series. For a visual assessment of the peak density of PCBs congeners on a retention plane, 2D images were compared. The degree of orthogonality of both column series was, along the visual assessment of distribution of PCBs on the retention plane, evaluated also by Pearson's correlation coefficient, which was found by correlation of retention times tR,i,2D and tR,i,1D of corresponding PCB congeners on both column series. It was demonstrated that the apolar + ionic liquid column series is almost orthogonal both for the 2D separation of PCBs present in Aroclor 1242 and 1260 formulations as well as for the separation of all of 209 PCBs. All toxic, dioxin-like PCBs, with the exception of PCB 118 that overlaps with PCB 106, were resolved by the apolar/ionic liquid series while on the apolar/polar column series three toxic PCBs overlapped (105 + 127, 81 + 148 and 118 + 106). 相似文献
A stainless steel wire coated with a polymeric ionic liquid (poly-IL) is shown to represent a viable new tool for solid-phase micro-extraction (SPME) of polychlorinated biphenyls (PCBs). The surface of the wire was covalently modified with 3-(trimethoxysilyl) propyl methacrylate, and susequent free-radical initiated polymerization of the ionic liquid (IL) 1-hexyl-3-vinylimidazolium bromide on the surface of the wire produced a poly-IL possessing sheet-like structure. The poly-IL fiber was evaluated with respect to its capability for extracting PCBs from water samples. The fiber aging temperature, extraction time, extraction temperature and ionic strength of the water sample were optimized. The poly-IL SPME fiber was applied to the headspace extraction of 12 kinds of PCBs (from PCB 81 to PCB 189) which, after direct injection into the port, were quantified by GC with ECD detection. The method displays good linearity in the 10 to 200 ng L?1 PCB concentration range, and limits of detection between 0.9 and 5.8 ng L?1. The single fiber and fiber-to-fiber repeatabilities are <10.7% and <12.7%, respectively. The method was applied to the analysis of PCBs in (spiked) Yangtze River water samples to give recoveries between 86.6 and 108%.
Graphical abstract A polymeric ionic liquid (poly-IL) was synthesized and anchored on the surface of a pre-treated stainless steel wire to produce a poly-IL solid-phase micro-extraction fiber that showed excellent headspace extraction of PCBs.
A high-performance liquid chromatography (HPLC) method using a column of 2-(1-pyrenyl) ethyldimethylsilylated silica was developed in this work in order to achieve satisfactory and reproducible fractionation of polychlorinated biphenyls (PCBs) from brominated flame retardants (BFRs) (polybrominated diphenylethers, PBDEs; and polybrominated biphenyls, PBBs). After the study of different chromatographic parameters (mobile phase composition and separation temperature were the most important) an isocratic elution with isooctane:toluene (98:2, v/v) at a flow-rate of 1 mL/min, a temperature of 45 °C, and UV-detection at 225 nm was selected for fractionation of PCBs (time region, 4.0-5.8 min) from PBDEs (5.8-9.0 min) and from PBBs (5.8-11.0 min). The applicability of this method to food samples was demonstrated by fractionating PCBs from PBDEs in three food samples (cheese, milk, and fish). Interferences from PCBs (present in real samples at much higher concentrations than PBDEs) were removed in this way. In addition, by analysing these samples by gas chromatography-mass spectrometry (GC-MS) with and without previous fractionation we were able to observe an improvement in detection sensitivity for PBDEs after HPLC fractionation. 相似文献
A reversed liquid-liquid partition system prepared from Chromosorb W, n-undecane and Carbowax 4000 monostearate was shown to be suitable for extracting organochlorine insecticides and polychlorinated biphenyls (PCBs) from water (with the exception of Aroclor 1260). The performances of the partition system, Amberlite XAD-4, porous poly- urethane foam and the solvent extraction technique when applied to the analysis of four environmental water samples were comparable (except for Aroclor 1260). 相似文献
A fast and robust assay, based on immuno-polymerase chain reaction (IPCR) techniques, was developed for the detection of polychlorinated
biphenyls (PCBs) in soil samples. Real-time IPCR (rt-IPCR) is a powerful technique that combines enzyme-linked immunosorbent
assay (ELISA) with the specificity and sensitivity of PCR. In our assay, indirect ELISAs based on immobilization of PCB37
hapten–ovalbumin conjugates was used for evaluation of the immune response. The effect of optimal reagent concentrations to
reduce background fluorescence was also investigated. Using the optimized assay, the linear sensitivity range of the assay
covered more than six orders of magnitude, and the minimum detection limits reached 5 fg ml–1 antigen. Rt-IPCR was tested for its cross-reactivity profiles using four selected congeners and four Aroclor products. The
assays were highly specific for congeners but less specific for Aroclor1242. We took four soil samples to validate the method,
and the results were confirmed by gas chromatography/mass spectrometry (GC/MS). The rt-IPCR results for soil samples correlated
well with the concentrations of PCBs obtained by GC/MS (r = 0.99, n = 6). These data indicate that this highly specific, sensitive, and robust assay can be modified for detecting PCB compounds
in the environment. 相似文献