超临界流体萃取在环境分析中的应用

按基体的不同形态综述了１９９３年以来超临界流体萃取在痕量环境污染物分析中的最新进展情况,５５篇。常见萃取分析的有机污染物主要包括多环芳烃、多氯联苯、二咕恶咕英、石油烃类、酚类化合物、农药和除草剂残留、金属离子和表面活性剂等。     

Monitoring polychlorinated biphenyls in pine needles using supercritical fluid extraction as a pretreatment method

This paper reports on the first use of supercritical fluid extraction (SFE) of polychlorinated biphenyls (PCBs) from pine needles. Supercritical carbon dioxide was used as extraction fluid, and exhibited good extraction efficiencies and recoveries (>90%). GC-MS (selected ion monitoring mode) achieved both accurate identification and quantification of the PCBs. Compared with traditional time consuming multi-step sample preparation methods, SFE with carbon dioxide is easier to perform, and is a feasible alternative extraction procedure for the monitoring of PCBs in pine needle samples.     

Microwave-assisted extraction of organochlorine compounds in marine sediments with organized molecular systems

Summary Analysis of marine sediments is particulary important because they are considered pollution indicators, since they present a view of the spatial distribution of pollutants. The use of microwave energy enables a simple and rapid analysis of different kinds of compounds present in these media. This work shows the results obtained during the optimization process for the application of microwave-assisted extraction methodology (MAE) to the determination of polychlorinated dibenzofurans (PCDFs), present in different marine sediment samples, as well as in mixtures with polychlorinated biphenyls (PCBs), using two non-ionic surfactants (oligoethylene glycol monoalkyl ether and polyoxyethylene 10 lauryl ether) as extractants. After extraction, the organochlorinated compounds are determined by HPLC using fluorescence detection. Recovery rates are compared with those obtained when Soxhlet extraction is used for the same purpose.     

Mesostructured cellular foam solid‐phase microextraction coating for the highly sensitive recognition of polychlorinated biphenyls in water samples

We herein presented a mesoporous cellular foam solid‐phase microextraction coating that showed highly sensitive recognition for weakly polarity polychlorinated biphenyls in water samples. The mesoporous cellular foam coater fiber was for the first time prepared by a simple sol‐gel method. The main experimental parameters including extraction temperature, extraction time, desorption time, stirring rate, and ionic strength were investigated by high‐efficiency orthogonal array design, a L₁₆ (4⁴) matrix was applied for the identification of optimized extraction parameters, and the optimized method was successfully applied to the analysis of environmental water sample. The novel mesoporous cellular foam coated fibers exhibited sensitive limits of detection (0.07–0.28 µg/L), wide linearity (5–3000 µg/L), and good reproducibility (3.5–8.3% for single fiber, and 4.9–8.7% for fiber‐to‐fiber) for polychlorinated biphenyls. The home‐made coating was successfully used in the analysis of polychlorinated biphenyls in real environmental water samples. These results indicate that the synthesized mesoporous cellular foams are promising materials for adsorption and separation applications in sample pretreatment.     

Fractionation of persistent organic pollutants in fish oil by high-performance liquid chromatography on a 2-(1-pyrenyl)ethyl silica column

The analysis of persistent organic pollutants in foodstuffs has become necessary for control of their levels in products for human and animal consumption. These analytical procedures usually require a fractionation step in order to separate the different families of pollutants to avoid interferences during the instrumental determination. In this study the separation was carried out on a 2-(1-pyrenyl)ethyl silica column, where analyte fractionation was based on differences in planarity and aromaticity. The fractionation of several types of persistent organic pollutants found in fish oil samples was studied; the pollutants included polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers, and some organochlorine pesticides. Fractions were analyzed by high-resolution gas chromatography with electron-capture detection and high-resolution gas chromatography–high resolution mass spectroscopy. Finally, the whole method (including the purification, fractionation, and instrumental determination steps) was validated and successfully applied to the analysis of several samples of fish oil.     

Advances in the gas chromatographic determination of persistent organic pollutants in the aquatic environment

Environmental chemists have been challenged for over 30 years to analyse complex mixtures of halogenated organic pollutants like polychlorinated biphenyls (PCBs), polychlorinated alkanes (PCAs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and polychlorinated furans (PCDD/Fs). Gas chromatography (GC) often proved to be the method of choice because of its high resolution. The recent developments in the field of comprehensive two-dimensional GC (GCxGC) show that this technique can provide much more information than conventional (single-column) GC. Large volume injection (e.g. by programmed temperature vaporiser, or on-column injection) can be employed for the injection of tens of microliters of sample extract, in that way substantially improving the detection limits. Electron-capture detection (ECD) is a sensitive detection method but unambiguous identification is not possible and misidentification easily occurs. Mass spectrometric (MS) detection substantially improves the identification and the better the resolution (as with MS/MS, time-of-flight (TOF) MS and high-resolution (HR)MS), the lower the chances of misidentification are. Unfortunately, this comes only with substantially higher investments and maintenance costs. Co-extracted lipids, sulphur and other interferences can disturb the GC separation and detection leading to unreliable results. Extraction, and more so, sample clean-up and fractionation, are crucial steps prior to the GC analysis of these pollutants. Recent developments in sample extraction and clean-up show that selective pressurised liquid extraction (PLE) is an effective and efficient extraction and clean-up technique that enables processing of multiple samples in less than 1h. Quality assurance tools such as interlaboratory studies and reference materials are very well established for PCDD/Fs and PCBs but the improvement of that infrastructure is needed for brominated flame retardants, PCAs and toxaphene.     

Dry ice-originated supercritical and liquid carbon dioxide extraction of organic pollutants from environmental samples

Packed in a high-pressure vessel and under calculated conditions, dry ice can be used as a source of carbon dioxide for supercritical CO₂ extraction or liquid CO₂ of organic compounds from environmental samples. Coupled with a fluid modifier such as toluene, dry ice-originated supercritical CO₂ (Sc CO₂) achieves quantitative extraction of many volatile organic compounds (VOCs) and semivolatile organic compounds (SOCs) including polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and polychlorinated biphenyls (PCBs) from solid matrices. Compared to contemporary manual or automated supercritical fluid extraction (SFE) technologies, this novel technique simplifies SFE to a minimum requirement by eliminating the need of a high-pressure pump and any electrical peripherals associated with it. This technique is highly suitable to analytical areas where sample preservation is essential but difficult in the sampling field, or where sample collection, sample preparation, and analysis are to be done in the field.     

Recent advances in the mass spectrometric analysis related to endocrine disrupting compounds in aquatic environmental samples

An overview of mass spectrometric methods used for the determination of endocrine disrupting compounds (EDCs) in environmental samples is presented. Among the EDCs we have selected five groups of compounds that are of priority within European Union and US research activities: alkylphenols, polychlorinated compounds (dioxins, furans and biphenyls), polybrominated diphenyl ethers, phthalates and steroid sex hormones. Various aspects of current LC-MS and GC-MS methodology, including sample preparation, are discussed.     

Determination of polybrominated diphenyl ethers in marine biological tissues using microwave-assisted extraction

Growing concern on the environmental impact of polybrominated diphenyl ethers (PBDEs) has created the need for rapid and quality assured analytical methods to quantify PBDEs in a spectrum of matrix types. This study presents the first validated method for the quantification of major PBDE congeners (47, 99 and 100) in marine biological tissues using microwave-assisted extraction (MAE). The recovery of polychlorinated biphenyls and various organochlorine pesticides has also been ascertained. Analytical accuracy, precision, limits of detection and cleanup efficiency were evaluated for PBDE congeners, and empirical data justifies the use of MAE for the extraction and analysis of PBDEs in biological matrices. MAE was also compared to Soxhlet extraction efficiency for PBDEs in the standard reference materials SRM2978 and SRM1588a and gave comparable results (<15% variation).     

Multi-determination of organic pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multi-determination method has been developed for the determination and confirmation of 68 organic pollutants in water samples by gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS). The following chemical families were determined in a chromatographic run of less than 26?min: polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenylethers (PBDEs), and pesticides (organochlorine, organophosphorus, triazine and others). The sample preparation involved a liquid-liquid extraction (LLE) procedure, obtaining recoveries ranging from 70 to 130% when dichloromethane was used as the extracting solvent. The detection limits of the proposed method were between 0.75 and 19.8?ng?L^?1. Samples from the Maipo River in central Chile were taken from 29 different points. Seven pesticides and two PAHs were detected in field collected samples with concentrations ranging from 10 to 95?ngL^?1. Concentrations of benzo[a]pyrene in environmental samples ranged from 25 to 33?ngL^?1 and were near the maximum levels established by the European Union Directives (50?ng?L^?1).     

Development of a method for simultaneous analysis of PCDDs, PCDFs, PCBs, PBDEs, PCNs and PAHs in Antarctic air

The development of a unique analytical method for the determination of five classes of persistent organic pollutants (POPs) in atmospheric gas and the particle phase through gas chromatography coupled to high-resolution mass spectrometry is presented. Every step of the pre-analytical and analytical optimization process is described. Great effort was put into simplifying the traditional techniques, with reference to EPA and literature methods. Automated instruments were used for sample extraction and cleanup in order to enhance repeatability and reduce contamination risks. Unlike most common approaches, no separation of the analytes was performed before the GC analysis in order to avoid sample fractionation and to save time and materials. This allowed low instrumental and method detection limits (pg to sub-pg) to be achieved. Accuracy and precision were tested by fortifying the matrix and analysing standard reference materials (NIST SRM 1649b Urban Dust and 2585 Organic Contaminants in House Dust). The method was applied to five samples from Terra Nova Bay, Antarctica. Concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) are presented. Lighter compounds dominate the distribution and are mainly present in the gaseous phase. The observed pattern may be attributable to long-range transport. Results are in general agreement with literature data, where available.     

Gas chromatography retention data of environmentally relevant polybrominated compounds

Polybrominated organic compounds are ubiquitous throughout the environment. This generic term comprises several classes of brominated flame retardants (e.g., polybrominated diphenyl ethers, polybrominated biphenyls, hexabromocyclododecane, dibromopropyltribromophenyl ether, 1,2-bis(2,4,6-tribromophenoxy)ethane) as well as a range of marine halogenated natural products (HNPs). Here we present gas chromatography retention times and elution orders (on DB-5) of 122 polybrominated compounds that may be found in food and environmental samples. Organobromine compounds in fish samples determined with gas chromatography interfaced to electron-capture negative ion mass spectrometry (GC/ECNI-MS) are discussed. The environmental relevance and important mass spectrometric features of the compounds are described as well. Our database aims to support the closer inspection and identification of peaks in gas chromatograms and to initiate dedicated screening for less frequently studied organobromines in samples.     

Sample handling strategies for the determination of persistent trace organic contaminants from biota samples

Even after emergence of most advanced instrumental techniques for the final separation, detection, identification and determination of analytes, sample handling continues to play a basic role in environmental analysis of complex matrices. In fact, sample preparation steps are often the bottleneck for combined time and efficiency in many overall analytical procedures. Thus, it is not surprising that, in the last two decades, a lot of effort has been devoted to the development of faster, safer, and more environment friendly techniques for sample extraction and extract clean up, prior to actual instrumental analysis. This article focuses on the state of the art in sample preparation of environmental solid biological samples dedicated to persistent organic pollutants (POPs) analysis. Extraction techniques such as Soxhlet extraction, sonication-assisted extraction, supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurised liquid extraction (PLE) and matrix solid-phase dispersion (MSPD) are reviewed and their most recent applications to the determination of POPs in biota samples are provided. Additionally, classical as well as promising novel extraction/clean-up techniques such as solid phase microextraction (SPME) are also summarized. Finally, emerging trends in sample preparation able to integrate analytes extraction and their adequate clean-up are presented.     

用于气相色谱和气相色谱-质谱测定植物样品中含氯有机污染物残留的样品前处理方法

根据植物样品中的主要干扰物质,建立了用于气相色谱(GC)和气相色谱-质谱联用(GC-MS)测定植物样品中含氯有机污染物残留的样品前处理方法,有效提高了对植物样品中有机氯农药及多氯联苯检测的灵敏度。采用均质提取法对样品进行提取,考察了凝胶渗透色谱(GPC)和固相萃取(SPE)对提取液的净化效果。结果发现,采用GC测定目标物时,提取液需经GPC和SPE两次净化;而采用GC-MS测定目标物时,仅用SPE一次净化即可。该方法快速、经济、灵敏,适合多种植物样品中有机污染物残留分析的样品前处理要求。     

Multiresidue method for the gas-chromatographic analysis of some polychlorinated and polybrominated pollutants in biological samples

Summary A multiresidue method for the analysis of a number of chlorinated and brominated organic compounds in biological samples has been developed. The method includes gas-chromatographic analysis of hexachlorinated and hexabrominated benzenes (HCB and HBB), polychlorinated and polybrominated biphenyls (PCB and PBB), polychlorinated phenols (PCP), guaiacols (PCG), paraffins (CP) and naphthalenes (PCN), polybrominated diphenyl ethers (PBDE) and the pesticides DDT, polychlorinated terpenes (PCC or toxaphene), chlordanes, hexachlorocyclohexanes (HCH), aldrin and dieldrin. The use of charcoal column in the clean-up procedure makes it also possible to analyze the planar PCB congeners (pPCB). Cod muscle samples were spiked with 10 and 50 times the detection levels of the compounds to be analyzed. The mean recoveries, relative to internal standards, for 40 compounds or compound groups were between 51 and 120%.     

Analysis of 51 persistent organic pollutants in soil by means of ultrasonic solvent extraction and stir bar sorptive extraction GC-MS

A novel method based on ultrasonic solvent extraction and stir bar sorptive extraction (SBSE) for the analysis of 51 persistent organic pollutants including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenylethers (PBDEs) in soil samples was developed. The different parameters that affect both the extraction of analytes from the soil samples, such as solvent selection, solvent volume, mass of soil, and extraction time, and the partitioning from the solvent/water mixture to the PDMS were studied. The final selected conditions consisted of the extraction of 1 g of soil with 15 mL methanol by sonication for 30 min. The methanol extract was mixed with 85 mL of Milli-Q water and extracted by means of SBSE for 14 h at 900 rpm. The stir bars were analyzed by thermal desorption-GC-mass spectometry (TD-GC-MS). The effects of the matrix on the recovery of the various pollutants under the developed method were studied using two soils with very different physicochemical properties. Method sensitivity, linearity, repeatability, and reproducibility were also studied. Validation and accuracy of the method were conducted by analyzing two commercial certified reference materials (CRMs). The main advantage of this method resides in the fact that a small amount of a nontoxic solvent (methanol) is needed for the extraction of only 1 g of solid sample allowing LODs ranging from 0.01 to 2.0 microg/kg. Repeatability and reproducibility variations were lower than 20% for all investigated compounds. Results of the CRMs verify the high accuracy of this method.     

Analysis and environmental levels of endocrine-disrupting compounds in freshwater sediments

An overview of analytical methods for target endocrine-disrupting compounds (EDCs) in freshwater sediments is presented. Among the EDCs we have selected five groups of compounds that are of priority within European Union and USA research activities: alkylphenols, polychlorinated compounds (dioxins, furans and biphenyls), polybrominated diphenyl ethers, phthalates and steroid sex hormones. Various aspects of current analytical methodology, such as sample preparation, extraction, purification and final determination, are discussed. Levels found in freshwater sediment are reviewed.     

Applications of On-Line SFE/SFC in Environmental Analysis

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated Pesticides (OCPs) on different absorbents were extracted and analyzed by a directly coupled supercritical fluid extraction and supercritical fluid chromatography system (on-line SFE/SFC). The influence of various absorbents as sample matrixes on extraction efficiencies was evaluated. In general, the extraction efficiencies were decreased if a matrix had a larger surface area and a smaller pore size. The recoveries of PAHs and PCBs were decreased in inverse proportion to their molar mass. Recoveries of OCPs containing epoxy functional groups were greater than for OCPs lacking this functional group. In conclusion, online SFE/SFC is a rapid (1-2 h) and high recovery (70%-100%) analytical technique.     

Gas chromatography–triple quadrupole tandem mass spectrometry: a powerful tool for the (ultra)trace analysis of multiclass environmental contaminants in fish and fish feed

A new method for rapid determination of 73 target organic environmental contaminants including 18 polychlorinated biphenyls, 16 organochlorinated pesticides, 14 brominated flame retardants and 25 polycyclic aromatic hydrocarbons in fish and fish feed using gas chromatography coupled with triple quadrupole tandem mass spectrometry (GC–MS/MS) was developed and validated. GC–MS/MS in electron ionization mode was shown to be a powerful tool for the (ultra)trace analysis of multiclass environmental contaminants in complex matrices, providing measurements with high selectivity and sensitivity. Another positive aspect characterizing the newly developed method is a substantial simplification of the sample preparation, which was achieved by an ethyl acetate QuEChERS (quick, easy, cheap, effective, rugged and safe) based extraction followed by silica minicolumn clean-up. With use of this sample preparation approach the sample laboratory throughput was increased not only because six samples may be prepared in approximately 1 h, but also because all the above-mentioned groups of contaminants can be determined in a single GC–MS/MS run. Under the optimized conditions, the recoveries of all target analytes in both matrices were within the range from 70 to 120 % and the repeatabilities were 20 % or less. The method quantification limits were in the range from 0.005 to 1 μg kg^–1 and from 0.05 to 10 μg kg^–1 for fish muscle tissue and fish feed, respectively. The developed method was successfully applied to the determination of halogenated persistent organic pollutants and polycyclic aromatic hydrocarbons in fish and fish feed samples.     

Advances in miniaturization and increasing sensitivity in analysis of organic contaminants in marine biota samples

In recent years there has been much progress in the miniaturization of sample treatment approaches for the analysis of organic contaminants. Whilst much focus has been given to analysis of liquid matrices (e.g., water, biological fluids), equivalent approaches for lipid rich biota samples have seen significantly less progress. This is especially the case for samples of very small organisms commonly employed as standard test species in ecotoxicity studies. Typically, the extractable biotic sample size available for body residue analysis is very small and the total pollutant accumulation can vary significantly between species types according to factors such as organism size, lipid content and exposure conditions. Depending on the physical and chemical characteristics of the analyte(s) in question, extraction and purification, especially from more complex matrices, appears to be one of the main bottlenecks in achieving their quantification. The current article presents a review of the available micro-extraction methods for small marine biota samples, focusing on environmentally important organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides.