Abstract The analysis of PCBs often involves lengthy and expensive cleanup procedures to remove interferences associated with environmental sample matrices. Gel permeation chromatography (GPC) has proven to be a useful tool in removing many of these interferences from environmental samples, especially from difficult matrices such as oils, lipids and sediments. This paper describes the effect of temperature upon the GPC column in separating PCBs from transformer oil and its implication on GC-MS analysis. 相似文献
Summary A simple, rapid, low cost and uniform single-step clean-up procedure with a column containing two silica gel packings of different mesh size for the quantitative determination of PCBs by capillary gas chromatography (ECD) is reported. Its application to 9 complex matrices, among them a transformer oil, a waste motor oil, and an oil from a tempering bath, shows that in contradiction to other clean-Up methods nearly all accompanying substances can be separated. The reproducibility of 4.7% and the recovery rate of 92.7% for the PCBs are comparable with data found in literature.
Einfaches Clean-up-Verfahren zur quantitativen Bestimmung von PCBs in komplexen Materialien
Chiral 2,2′,3,5′,6-pentachlorobiphenyl (PCB 95), 2,2′,3,3′,4,6′-hexachlorobiphnyl (PCB 132) and 2,2′,3,4′,5′,6-hexachlorobiphenyl (PCB 149) were quantified in Atlantic Ocean shark liver samples (C. coelolepis) by gas chromatography-mass spectrometry (GC-MS) and their enantiomeric ratios were studied by multidimensional gas chromatography (MDGC) with an achiral-chiral column combination and detected by ECD and MS/SIM. The concentration range of the chiral PCBs was from 2 to 6 ng/g (fresh weight), which represents 2–6 % of the total PCB mean concentration. The investigations revealed a small enantiomeric bias of PCB 132 in most of the samples studied (ER = 0.75–0.89, ee = 6–14%), while PCB 95 and PCB 149 were present in racemic or almost racemic form. 相似文献
There is a need for cost-efficient alternatives to gas chromatography (GC)–high-resolution mass spectrometry (HRMS) for the
analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in food and feed. Comprehensive two-dimensional
GC–micro electron capture detection (GC×GC-μECD) was tested and all relevant (according to the World Health Organisation,
WHO) PCDD/Fs and PCBs could be separated when using a DB-XLB/LC-50 column combination. Validation tests by two laboratories
showed that detectability, repeatability, reproducibility and accuracy of GC×GC-μECD are all statistically consistent with
GC-HRMS results. A limit of detection of 0.5 pg WHO PCDD/F tetrachlorodibenzo-p-dioxin equivalency concentration per gram of fish oil was established. The reproducibility was less than 10%, which is below
the recommended EU value for reference methods (less than 15%). Injections of vegetable oil extracts spiked with PCBs, polychlorinated
naphthalenes and diphenyl ethers at concentrations of 200 ng/g showed no significant impact on the dioxin results, confirming
in that way the robustness of the method. The use of GC×GC-μECD as a routine method for food and feed analysis is therefore
recommended. However, the data evaluation of low dioxin concentrations is still laborious owing to the need for manual integration.
This makes the overall analysis costs higher than those of GC-HRMS. Further developments of software are needed (and expected)
to reduce the data evaluation time. Combination of the current method with pressurised liquid extraction with in-cell cleanup
will result in further reduction of analysis costs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
An automated method for the direct analysis of polychlorinated biphenyls (PCBs) in transformer oil is presented. The proposed method uses the TOTAD (through oven transfer adsorption desorption) interface for the on-line coupling of reversed phase liquid chromatography and gas chromatography (RPLC-GC). In this fully automated system, the oil is injected directly with no sample pre-treatment step other than dilution with n-propanol and filtration. In the LC step, PCBs are separated from other components of the oils using methanol/water (90:10 v/v) as mobile phase, at a flow rate of 1?mL?min?1. The LC fraction containing the PCBs is automatically transferred to the GC by the TOTAD interface and GC analysis enables the separation of the PCB congeners. The proposed method is compared with two other methods: the European Norm (UNE-EN-61619) and that of the American Society for Testing and Materials (ASTM) (D4059-00). The proposed method practically eliminates the time-consuming sample preparation step and avoids errors caused by sample manipulation. The total PCB concentrations obtained with the three methods are similar. 相似文献
Four mineral oil certified reference materials (CRMs), NMIJ CRM 7902-a, CRM 7903-a, CRM 7904-a, and CRM 7905-a, have been
issued by the National Metrology Institute of Japan, which is part of the National Institute of Advanced Industrial Science
and Technology (NMIJ/AIST), for the determination of polychlorinated biphenyls (PCBs). The raw materials for the CRMs were
an insulation oil (CRM 7902-a and CRM 7903-a) and a fuel oil (CRM7904-a and CRM 7905-a). A solution of PCB3, PCB8, and technical
PCB products, comprising four types of Kaneclor, was added to the oil matrices. The total PCB concentrations in the PCB-fortified
oils (CRM 7902-a and CRM 7904-a) are approximately 6 mg kg−1. In addition, the mineral oils which were not fortified with PCBs were also distributed as CRMs (CRM 7903-a and CRM 7905-a).
Characterization of these CRMs was conducted by the NMIJ/AIST, where the mineral oils and the PCB solution were analyzed using
multiple analytical methods such as dimethylsulfoxide extraction, normal-phase liquid chromatography, gel permeation chromatography,
reversed-phase liquid chromatography, and chromatography using sulfoxide-bonded silica; and/or various capillary columns for
gas chromatography, and two ionization modes for mass spectrometry. The target compounds in the mineral oils and those in
the PCB solution were determined by one of the primary methods of measurement, isotope dilution–mass spectrometry (ID-MS).
Certified values have been provided for 11 PCB congeners (PCB3, 8, 28, 52, 101, 118, 138, 153, 180, 194, and 206) in the CRMs.
These CRMs have information values for PCB homologue concentrations determined by using a Japanese official method for determination
of PCBs in wastes and densities determined with an oscillational density meter. Because oil samples having arbitrary PCB concentrations
between respective property values of the PCB-fortified and nonfortified CRMs can be prepared by gravimetric mixing of the
CRM pairs, these CRMs can be used for validation of PCB analyses using various instruments which have different sensitivities.
Figure Preparation and certification processes of the mineral oil CRMs (example shown is polychlorinated biphenyls in insulation
oil, high/low concentrations)
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Polychlorinated biphenyls are persistent organic pollutants that can be metabolized via hydroxylated PCBs to PCB sulfate metabolites.
The sensitive and selective analysis of PCB sulfate monoesters by gas chromatography-mass spectrometry (GC-MS) requires their
derivatization, for example, as PCB 2,2,2-trichloroethyl (TCE) sulfate monoesters. To aid in the identification of unknown
PCB sulfate metabolites isolated from biological samples, the electron impact MS fragmentation pathways of selected PCB TCE
sulfate diesters were analyzed and compared to the fragmentation pathways of the corresponding methoxylated PCBs. 相似文献
In this study, a silica stationary phase modified with sulfoxide group and ammonium-salt was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic sulfide was attached to a diamino (primary and secondary amino) bonded silica surface by an amide bond, and the bonded sulfide groups were oxidized with periodate to afford sulfoxide groups bonded to the stationary phase. The secondary amino groups in the spacer chain were converted to ammonium-salt by the addition of hydrochloric acid. The sulfoxide group and ammonium-salt bonded stationary phase was tested for their suitability as adsorbent for SPE-type preparative short columns and for an analytical HPLC-type separation. The new stationary phase (1.2 mmol of sulfur bonded per gram) separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than previously reported stationary phases including sulfoxide group or ammonium-salt bonded ones. The quantitative chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners also indicated strong retention of highly chlorinated biphenyls by the sulfoxide and ammonium-salt bonded silica compared with simple aminopropyl, sulfoxide group or ammonium-salt bonded ones. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using sulfoxide group and ammonium-salt bonded silica packed column fractionation. The analytical method, combination of the cleanup procedure, and measurement with a GC-high resolution (magnetic sector) MS or a GC-quadrupole MS were validated using mineral oil certified reference materials. 相似文献
Polychlorinated biphenyls (PCBs) are among the most ubiquitous pollutants in the environment, and their metabolism leads to the formation of hydroxylated PCBs (OH-PCBs) and methyl sulfone PCBs (MeSO2-PCBs). These metabolites are generally more hydrophilic than the parent compound, and therefore are more easily eliminated from the body. However, some congeners have been shown to be strongly retained in human blood, binding to transthyretin with an affinity that is, in general, greater than that of the natural ligand thyroxin itself, which could result in toxicological effects, particularly on the thyroid system. Currently available analytical methods require, in general, extensive sample preparation, which includes a series of time-consuming and low-throughput liquid–liquid and back extractions, evaporations, several cleanup steps, and in some cases, derivatization prior to analysis by gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS). Recent developments in the use of LC coupled with tandem MS (MS/MS) have brought some improvements in terms of sample preparation for the determination of PCB metabolites in blood, although there are still possibilities for continued development. The selected literature has evidenced few studies of LC–MS/MS-based methods, a lack of analytical standards, nonassessment of lower-chlorinated OH-PCBs, and scarce attention to MeSO2-PCBs in blood. This review aims to evaluate critically the currently available analytical methods for determination of OH-PCBs and MeSO2-PCBs in blood. 相似文献
Abstract A rapid and reliable analytical method, at trace level concentration was developed and validated for monitoring polychlorinated biphenyls (PCBs) in Jordanian surface water. The method combines the advantage of liquid extraction together with gas chromatography‐mass spectrometry (GC/MS) and gas chromatography‐electron capture detector (GC/ECD). The performance of the method was evaluated by analyzing certified reference material (CRM) of the analytes and applied on real water samples collected from different sites in Jordan. A mixture of 60∶40 dichloromethan‐petroleum ether was chosen as a convenient binary solvent for liquid–liquid extraction. The GC conditions for GC/MS were optimized using He as a carrier gas, temperature programming, and chlorpropham as an internal standard (IS). The conditions for GC/ECD were performed using N2 gas and a temperature program from 160 to 280°C with different increasing rates. The method of GC/MS in the selective ion mode (SIM) gave linear relationships for all PCBs tested between 0.60–6.0 µg/l with R2=0.9934 (n=7×18). Recoveries from spiked water samples ranged between 87.6 and 91.4%. The mean accuracy and precision obtained were 4.9% and 2.16%, respectively. The mean of detection limit was 0.14±0.04 µg/l. In GC/ECD, linear relationships for all PCBs examined over the range of 0.3–2.4 µg/l was verified as characterized by a linear regression equation and correlation coefficient, R2=0.9915 (n=12). The average precision and accuracy were 4.86% and 5.21%, respectively. Analyses results clarified that none of the examined Jordanian water samples contained any of the searched for PCBs within the detection limit achieved. 相似文献
PCB patterns in a new pigment brand are characterized using GC-MS in the single ion monitoring (SIM) mode. Specific PCBs are then used as external standards for GC-ECD quantification. The following PCB isomers or groups of isomers have to be determined (CB = chlorobiphenyl): total diCBs, 3,3′ diCB, 2,4,5-triCB, 2,2′,4,4′-tetraCB, 2,2′,5,5′-tetraCB, total pentaCB, total hexaCB. Capillary gas chromatography is performed on preseparated solutions (LC) of pigment. An electron caputure detector (ECD) is used for PCB detection and quantification. Calibration is based on the peak areas of external standards and the PCB isomers in the samples, all normalized for internal standard peak areas. Total concentrations of diCB, hexaCB, or pentaCB in a sample are calculated by summing the individual PCB isomer concentrations within the correcsponding elution ranges. Determination limits lie in the range of 1 mg/PCB-isomer/kg pigment. 相似文献
A method for the determination of polychlorinated biphenyls (PCB) by fast gas chromatography coupled with mass-spectrometric detection in selective ion monitoring mode has been developed.
Chromatographic separation was carried out with HT-8 column (30 m × 0.25 mm) under sharp temperature increase from 80 to 320°C
at a rate of 40°C/min. Duration of chromatography is 10 min. Fast chromatography conditions suggested by authors makes it
possible to increase S/N ratios 10 times and so to reduce significantly the representative weight of the sample and develop an effective sample preparation
technique. The method was used for PCB determination in Baikal area samples such as soil, snow, sediments from Lake Baikal
and its tributaries, tissues of Baikal omul (Coregonus migratorius, Georgi, 1775) and blubber of Baikal seal (Phoca sibirica Gm.). The sample preparation stage includes PCB extraction from environmental samples and hydrolyzate of biological material
with the following cleanup of the extract on the compact silica gel and florisil cartridges (0.5 g of the sorbent). The method
enables the measurements of total PCBs and isomer groups of the same chlorination level with interlaboratory precision of
no greater than 10% and the determination of indicator congeners (PCBs 28, 52, 101, 118, 138, 153, and 180) with a precision
not exceeding 15%. 相似文献
Moss (Pleurozium schreberi) was investigated as biomonitor of atmospheric polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Samples were collected at a distance of 10, 50 and 100 m from a highway and were seasonally collected in a forest stand near a regional background air pollution station situated approximately 30 km from the highway. The samples from the background area were dried using two different techniques in parallel, air-drying and freeze-drying. Simultaneous pressurised liquid extraction of PAHs and PCBs was performed, followed by purification using gel permeation chromatography of the crude extract. The concentration of the 15 most important Environmental Protection Agency (EPA) PAHs was determined by gas chromatography coupled with ion-trap mass spectrometry with a selected ion storage acquisition programme, and the PCB concentrations were determined using a mass spectrometer operated in tandem mass spectrometry (MS/MS) mode. Acceptable recoveries and quality parameters for PAHs and PCBs were achieved with the use of pressurised liquid extraction followed by gel permeation chromatography. The detection limit was <0.76 ng g?1 for PAHs and <0.04 ng g?1 for PCBs. Possible contamination of the moss samples by 3-ring PAHs and PCBs in the atmosphere was found during air drying. Increased PAH and PCB concentrations caused by car engine exhausts and by asphalt and oil evaporation were found near the highway. Generally, the PAH and PCB concentrations in moss decreased exponentially with distance from the highway. The organic compound concentrations close to the background station showed seasonal fluctuations corresponding to the fluctuations in the local air temperature and particle concentration. 相似文献
We present the first study on the analytical methods of phenyltin compounds (PTs) in polychlorinated biphenyl (PCB)-based transformer oil samples. Tetraphenyltin (TePhT) has been used as stabilizer for some kinds of PCBs-based transformer oil formulations. Monophenyltin (MPhT), diphenyltin (DPhT) and triphenyltin (TrPhT) could have been formed from TePhT during long-term use. TePhT was directly measured by gas chromatograph (GC) connected with three types of detectors, a mass spectrometer (MS), a flame photometric detector (FPD) and an atomic emission detector (AED) after dilution with hexane. MPhT, DPhT and TrPhT were propylated with Grignard reagent before measurement. The MS was the most sensitive of the detectors, with detection limits of phenyltin compounds of 30 ng/ml (MPhT), 9.8 ng/ml (DPhT), 5.5 ng/ml (TrPhT) and 0.60 ng/ml (TePhT), respectively. From the viewpoint of selectivity, MS was slightly worse than other detectors, but interference from PCBs matrices was not significant under ordinary analytical conditions. Two used transformer oil samples were analyzed using the analytical methods developed in this study. TePhT and TrPhT were found in both samples. 相似文献
Abstract High resolution capillary gas chromatographic analysis of the polychlorobiphenyls (PCBs) present in snapping turtle eggs, provided quantitative data on selected toxic congeners. The concentrations of these congeners have been converted into equivalent toxic concentrations of 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD). The toxic equivalent factors (TEFs), necessary to effect this transformation were derived from EC50 values (half the concentration of the toxic congener required to produce the maximum effect) for aryl hydrocarbon hydroxylase (AHH) induction associated with the corresponding toxic PCB congener or isomer. Summation of the resulting toxic equivalents provided a composite assessment of the toxlcity of the PCB mixture in terms of an equivalent concentration of TCDD. 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.
After the restrictions on production and use of PCBs, Ugilec 141, a technical mixture of dichlorobenzyldichlorotoluenes (DBDTs), has been used as a PCB substitute in hydraulic systems. In the Netherlands, the production, import and use of Ugilec 141 has been forbidden since 1988. A method has been developed for the analysis of Ugilec 141 in waste mineral oils to control waste oil import and processing. The method development was based on modification of procedures for the analysis of PCBs in oil and dioxins in fatty matrices and analysis was performed with gas chromatography with mass spectrometry. For sample clean-up, several combinations of column chromatography with activated carbon, alumina, and silica gel have been tested to obtain extracts free from matrix interferences. An internal standard of 13C-labeled DBDT was examined to check recoveries from the clean-up procedures. Quantification was performed by comparison with the six most abundant peaks of an external Ugilec 141 standard mixture. Validation experiments showed a linear range from 0.25 to 60 mg Ugilec 141 kg?1 oil, a reproducibility of 3% and a limit of determination of 0.25 mg Ugilec 141 kg?1 waste oil. The method was applied in a survey of 70 samples of waste mineral oils from producers all over the Netherlands; this revealed levels below the limit of determination and one positive sample with a concentration of 5.7±0.1 mg Ugilec 141 kg?1 oil. In an inspection inquiry, one contaminated oil was found containing 116 ± 9 g Ugilec 141 kg?1 oil. 相似文献
Abstract The earthworm's (Lumbricus rubellus) uptake of polychlorinated biphenyls (PCBs) from a soil contaminated with a commercial PCB formulation (Askarel at 150 μg g?1) and their elimination of PCBs into a low contaminated soil (15 μg g?1) has been studied. 17 individual congeners were monitored. The uptake and the elimination rate were similar for all PCB congeners notwithstanding their different chloro-substitution pattern which suggested that bioaccumulation of PCBs in earthworms is governed by passive, possibly diffusion controlled processes. The equilibrium state in the three-phase system, soil/soil water/earthworm was reached with a half-time around 3–4 days. The soil to earthworm bioconcentration factor ranged from 4 to 20 for tetra- to octa-chlorinated biphenyls and was weakly depending on the octanol-water partition coefficient: BCF = ?(1.3?1.8) × KOW(0.35?0.40). 相似文献