Comprehensive two-dimensional gas chromatography of polybrominated diphenyl ethers

Comprehensive two-dimensional gas chromatography with micro electron-capture detection (GCxGC-muECD) was evaluated for the separation of 125 polybrominated diphenyl ethers (PBDEs). From among the six column combinations that were evaluated, DB-1x007-65HT was found to be the most suitable because of: (i) the highest number of BDE congeners separated; (ii) the least decomposition of higher brominated congeners; and (iii) the most suitable maximum operating temperature. The separation of the 125 BDE congeners from five hydroxy- and two methoxy-BDEs and nine other brominated flame retardants (polybrominated biphenyls, tetrabromobisphenol-A, methyl-tetrabromobisphenol-A and hexabromocyclododecane) was also studied. Fluorinated BDEs were found to be valuable internal standards for the determination of BDEs because of their very similar physico-chemical properties and excellent separation from the parent BDEs, mainly in the second dimension. GCxGC-time-of-flight MS and GCxGC-muECD were shown to be useful tools to identify decomposition products of nona- and deca-substituted BDEs, which are formed during the GC run. Three nona-BDEs were shown to be the major decomposition products of BDE 209.     

Determination of Polybrominated Diphenyl Ethers in Coastal and River Sediments by Pressurized Liquid Extraction Coupled with Gas Chromatography‐Mass Spectrometry

This study presents a time‐ and solvent‐saving method, pressurized liquid extraction (PLE), to extract polybrominated diphenyl ethers (PBDEs) in sediment samples. The effects of various operating parameters (i.e., extraction solution, temperature, pressure, static/dynamic extraction times) for the quantitative extraction of PBDEs by home‐made PLE were systematically investigated and optimized. The analytes were then identified and quantitated by gas chromatography‐mass spectrometry (GC‐MS) in selected ion monitoring (SIM) mode. The 16 PBDE congeners (from tri‐ to deca‐BDE) can be completely extracted by dichloromethane: n‐hexane (3/2, v/v) at 100 °C and 100 atm combined with 15 min static and then 15 min dynamic extraction steps. Recovery of PBDEs in spiked sediment samples ranged from 52 to 104% with 2‐16% RSD, except for BDE‐206. Limits of quantitation (LOQ) were established between 4 and 400 pg/g (dry weight) in 10 g of sediment sample. The extraction efficiency of the PLE was also compared with the traditional Soxhlet extraction method. The total contents of PBDEs ranged from 8.0 to 37.9 ng/g (dry weight) in various river and coastal sediment samples in Taiwan. Deca‐BDE (BDE‐209) was the major PBDE detected in these sediment samples.     

Individual determination of ortho and non-ortho substituted polychlorobiphenyls (PCBs) in sediments by high performance liquid chromatographic pre-separation and gas chromatography/ECD detection

Summary An analytical procedure for the individual determination of ortho and non-ortho PCB congeners in sediments, using high performance liquid chromatography (HPLC) preseparation and gas chromatography/ECD detection, is described. Gas chromatography/FTIR spectrometry (GC/FTIR) and gas chromatography/mass spectrometry (GC/MS) were employed for individual congener identification and determination. Sample extraction, clean-up of extract and selective elution procedures were optimized by using reference certified marine sediment samples. Recovery and precision were typically 83% and 16% respectively at 2 ng/g of total PCB content. The proposed procedure, tested by analyzing real sediment samples, showed a reproducibility better than 20% at 13 ng/g PCB level.     

Gas chromatography/ion trap mass spectrometry applied for the determination of polybrominated diphenyl ethers in soil

A gas chromatography/ion trap mass spectrometry (GC/ITMS) method was developed for the determination of polybrominated diphenyl ethers (PBDEs). ITMS parameters were optimized in order to achieve the best sensitivity for the PBDE analysis. Tandem mass spectrometry, along with an isotope dilution internal standard method, was used for the quantitation. Chromatographic windows were developed for mono- to hepta-BDEs, depending on the retention times when a 30-m GC column was used. A different 15-m column was used to analyze deca-BDE. Environmental soil samples collected from an electronic waste recycling site were prepared by using Soxhlet extraction and column chromatographic cleanup. Average recoveries of 61-118% were obtained for the 13C-labeled PBDE internal standards spiked in the samples prior to sample preparation. The accuracy represented by relative analytical errors was -24% to 18%, and the precision (relative standard deviation) was 11-26% (n=8). The method detection limits ranged from 0.013-0.25 ng/g for the PBDEs in soil.     

Retention-time database of 126 polybrominated diphenyl ether congeners and two bromkal technical mixtures on seven capillary gas chromatographic columns

The elution order of 126 polybrominated diphenyl ethers (PBDE) was determined for seven different gas chromatographic (GC) stationary phases. The resulting database facilitates selection of the most suitable GC columns for developing a quantitative, congener-specific BDE analysis and the testing of retention prediction algorithms based on structure relationships of GC phases and congener substitution patterns. In addition, co-elutions of the principal BDE congeners with other BDEs and/or with other brominated flame retardants were investigated and, as an application, the composition of two Bromkal mixtures (70-5DE and 79-8DE) was studied.     

Quantitative analysis of polybrominated diphenyl ethers in earthworms and soil by gas chromatography coupled to ion-trap tandem mass spectrometry

A method coupling gas chromatography to ion-trap tandem mass spectrometry (GC/ITMS) was developed and optimized for the analysis of polybrominated diphenyl ethers (PBDEs) in soil and earthworms. It was found that the molecular ion [M]+ cluster provided better performance than the [M-2Br]+ as a collision-induced dissociation (CID) precursor ion for most congeners when considering sensitivity, specificity and potential interference from complicated matrices. Other parameters such as the resonant excitation voltage, 'q' value, were also optimized. To evaluate the suitability of the ITMS method, the optimized method was applied for the analysis of PBDEs in different samples including earthworms and soil, and its performance was compared with that of selected ion monitoring (SIM). It was found that ITMS offered higher sensitivity than SIM when analyzing real environmental samples.     

全二维气相色谱-电子捕获检测器法分析土壤中毒杀芬同类物的残留

建立了全二维气相色谱-电子捕获检测器(GC× GC-μECD)检测土壤中毒杀芬同类物的分析方法.以非极性的DB- XLB(20 m×0.25 mm×0.25 μm)为第一色谱柱,中等极性的BPX-50(2 m×0.1 mm×0.1 μm)为第二色谱柱,对土壤中23种高关注毒杀芬同类物进行了分离鉴定,并采用基质曲线外标法进行定量分析.本方法在1～200,μg/L浓度范围内,毒杀芬同类物的线性相关系数(r2)均大于0.99,方法检出限(S/N=3)为0.039～0.482 μg/L,基质加标毒杀芬同类物的回收率为55％～115％,相对标准偏差(RSD)均小于30％(n=5).利用本方法对毒杀芬污染的土壤样品进行了测定,获得了较好的分离效果.     

HPLC isolation and NMR structure elucidation of the most prominent octabromo isomer in technical octabromo diphenyl ether

The major octabromo isomer of technical octabromo diphenyl ether mixture (technical octaBDE) DE-79 was isolated by RP-HPLC. Three serially coupled columns (each 250 mm long) enabled a good separation of the target compound from other congeners using 100% ACN as eluent. Approximately 100 microg of the target compound was isolated with a purity of >90% and investigated by MS for confirmation of the degree of bromination. 1H-NMR and 2-D 1H-13C correlation NMR spectra unequivocally clarified that the octaBDE in question is 2,2',3,3',4,4',6,6'-octabromodiphenyl ether (BDE 197). Based on annual production rates of technical BDE products (1999/2001), approximately 380 tons of BDE 197 were annually produced which, on the long term, may enter the environment. Compared with other individual BDE congeners, BDE 197 has the seventh highest application rate. Reductive debromination of BDE 197 can lead to four hepta-, 15 hexa-, 23 penta-, and 28 tetra-BDE isomers, respectively. This variety includes all known major BDEs of environmental concern (BDE 47, 85, 99, 100, 153, 154, and 183). The identification of BDE 197 in technical octaBDE DE-79 strongly suggests that research on the environmental fate of BDEs should include this key-BDE congener.     

Microwave-assisted extraction (MAE) for the determination of polybrominated diphenylethers (PBDEs) in sewage sludge

An efficient microwave-assisted extraction (MAE) method has been developed and evaluated for the quantification of eight major polybrominated diphenylethers (PBDEs) in sewage sludge. The PBDEs were extracted from wet and dry sludge in a microwave extraction unit using a hexane/acetone mixture for 35 min at a controlled temperature of 130 °C. The extract was concentrated, cleaned up on a silica gel column, and analyzed by gas chromatography/mass spectrometry (GC/MS) in the negative chemical ionization (NCI) mode. The MAE procedure exhibited higher extraction efficiency, specifically for BDE (brominated diphenylether) 209, than the conventional Soxhlet extraction. The test congeners were clearly separated under specific instrumental operating conditions, at a source temperature of 230 °C and a column length of 20 m. The present analytical method showed recovery efficiencies ranging from 80 to 110% when applied to the PBDE-free sludge spiked with eight PBDE congeners. The efficiency of the MAE method was confirmed using sludge obtained from four sewage treatment plants (STPs). The results indicate that BDE 47, 99, and 209 are the most abundant congeners present in these sewage sludges, which is consistent with previous reports.     

Determination of polybrominated diphenyl ethers in indoor dust standard reference materials

Polybrominated diphenyl ethers (PBDEs) have been measured for the first time in three different indoor dust Standard Reference Materials (SRMs) prepared by the National Institute of Standards and Technology (NIST). Two of these, SRM 2583 (Trace Elements in Indoor Dust) and SRM 2584 (Trace Elements in Indoor Dust), have been certified previously for lead and other inorganic constituents. A third, SRM 2585 (Organics in Indoor Dust), is a new indoor dust reference material prepared by NIST which will be certified for various organic compounds (polycyclic aromatic hydrocarbons, pesticides and polychlorinated biphenyls) in 2005 including certified concentrations for 16 individual PBDE congeners and reference values for an additional three PBDE congeners. Dust SRMs were analyzed for 30 PBDE congeners using high-resolution gas chromatography combined with low-resolution mass spectrometry operated in both negative chemical ionization (GC/ECNI–MS) and electron impact ionization (GC/EI–MS) modes. Sensitivity was an order of magnitude higher using GC/ECNI–MS relative to GC/EI–MS. These SRMs have been characterized and compared to the three PBDE commercial products (pentaBDE, octaBDE and decaBDE). PentaBDE and DecaBDE were present in all three SRMs and were the dominant commercial products, making up approximately 33% and 58%, respectively. Recent studies suggest that house dust may be a leading source of human exposure to PBDEs. These SRMs are the first reference materials with certified concentrations for PBDEs, which will aid in validating future measurements of PBDEs in house dust and other similar matrices. Electronic Supplementary Material Supplementary material is available for this article at http://dx.doi.org/ 10.1007/s00216-005-0227-y     

Focused ultrasound solid–liquid extraction and gas chromatography tandem mass spectrometry determination of brominated flame retardants in indoor dust

This study presents a focused ultrasound solid-liquid extraction (FUSLE) and gas chromatography tandem mass spectrometry method for the determination of brominated diphenyl ethers (BDEs), from mono- to hexa-congeners, in indoor dust. This approach provided a simple, fast, and economical method. After the solvent extraction selection, the FUSLE conditions were studied using a central composite design. Finally, the number of extraction cycles was studied. The selected conditions were 8?mL of 3:1 n-hexane-acetone mixture as extraction solvent, at a power of 65% for 20?s. The proposed method allowed accurate determination of BDEs, with recovery values around 100% and detection limits between 0.05 and 0.8?ng?g(-1). It also has advantages over other existing methods in terms of simplicity, analysis time, and solvent consumption. The analysis of several indoor dust samples showed high concentration values of BDEs 47, 99, 100, 153, and 154 in some of the samples, moreover, BDEs 47 and 99 were found in all samples.     

超声辅助萃取-气相色谱-负化学电离源质谱法测定室内灰尘样品中8种常见多溴联苯醚

建立了室内灰尘样品中8种常见多溴联苯醚(PBDEs: BDE-28、BDE-47、BDE-99、BDE-100、BDE-153、BDE-154、BDE-183和BDE-209)的气相色谱-负化学电离源质谱(GC-NCI/MS)分析方法。样品经吸尘器采集、正己烷超声萃取、浓缩后,采用GC-NCI/MS测定。结果表明,方法的加标回收率为53.2%～107.6%,日内测定的相对标准偏差(RSD)为2.8%～16.5%,日间测定的RSD为6.4%～22.6%。除了BDE-209的检出限(信噪比为3)为0.15 ng/g外,其他多溴联苯醚的检出限为0.003～0.015 ng/g。该方法灵敏度高,准确度和精密度好,简便快速,溶剂消耗量少,适用于灰尘中三溴～十溴联苯醚的测定。     

Gas chromatography/ion trap tandem mass spectrometry for the analysis of halobenzenes in soils by solid-phase microextraction

Headspace solid-phase microextraction combined with gas chromatography/ion trap tandem mass spectrometry (HS-SPME/GC/ITMS/MS) was used for the analysis of 12 halobenzenes from soil samples. For MS/MS optimisation, the experiments were performed by precursor ion selection and software controlled operations. Collision-induced dissociation (CID) can be achieved by two different approaches, resonant and non-resonant excitation modes. Different results were obtained using the two approaches, and the resonant excitation mode was chosen as the best for all halobenzenes. Parameters such as the CID excitation amplitude, excitation RF storage level and CID bandwidth frequency were optimised to maximise the formation of halobenzene product ions. A 100-microm polydimethylsiloxane fibre was used for the isolation and preconcentration of the analytes. The HS-SPME/GC/ITMS/MS method was applied to the analysis of halobenzenes in an agricultural soil sample. The halobenzenes were quantified by standard addition, which led to good reproducibility (RSD between 4.7 and 9.2%) and detection limits in the low pg/g range. The method was validated by comparing the results with those obtained in a European inter-laboratory exercise.     

Analysis of polybrominated diphenyl ethers in sewage sludge by matrix solid‐phase dispersion and isotope dilution GC–MS

A method for the determination of 14 polybrominated diphenyl ethers (PBDEs) in sludge from wastewater treatment plants is presented. PBDEs were extracted by matrix solid‐phase dispersion assisted by sonication and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode, using labelled ¹³C‐PBDEs as internal standards. The limits of detection and quantification for the tri‐ to hepta‐BDEs were in the range of 0.05 to 0.5 ng/g dry weight and 0.15 to 1.8 ng/g dry weight, respectively, and 1.6 ng/g dry weight and 5.6 ng/g dry weight for deca‐BDE‐209. The proposed analytical method was applied to determine PBDE levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In all of the examined samples, BDE‐100 and BDE‐154 were the main compounds found with a mean concentration of 3.9 and 2.0 ng/g, respectively. PBDEs were detected in all of the samples, and their total concentrations not considering BDE‐209 were between 3.9 and 23.0 ng/g dry weight. The dominant PBDE congener in sewage sludge was BDE‐209, which constituted 38.7 to 97.3% of the total, and showed concentration levels ranging from 8.1 to 717.2 ng/g dry weight.     

Gas chromatography/mass spectrometry of polychlorinated biphenyls using atmospheric pressure chemical ionization and atmospheric pressure photoionization microchips

Gas chromatography (GC) and ion trap mass spectrometry (MS) were combined with microchip atmospheric pressure chemical ionization (microAPCI) and microchip atmospheric pressure photoionization (microAPPI) sources. Selected polychlorinated biphenyls (PCBs, IUPAC Nos. 28, 52, 101, 118, 138, 153 and 180) were analyzed by GC/microAPCI-MS and GC/microAPPI-MS to demonstrate the applicability of the miniaturized ion sources in negative ion mode analysis. The microAPCI and microAPPI methods were evaluated in respect of detection limit, linearity and repeatability. The detection limits for the PCB congeners were somewhat lower with microAPCI than with microAPPI, whereas microAPPI showed slightly wider linear range and better repeatability. With both methods, the best results were obtained for highly chlorinated or non-ortho-chlorinated PCBs, which possess the highest electron affinities. Finally, the suitability of the GC/microAPPI-MS method for the analysis of PCBs in environmental samples was demonstrated by analyzing soil extracts, and by comparing the results with those obtained by gas chromatography with electron capture detection (GC/ECD).     

同位素稀释-气相色谱-串联质谱法测定土壤中的指示性毒杀芬

建立了土壤样品中指示性毒杀芬Parlar No.26 (P26)、Parlar No.50 (P50)和Parlar No.62 (P62)的同位素稀释-气相色谱-串联质谱(ID-GC-MS/MS)的分析方法。土壤样品使用压力溶剂萃取装置(PLE)提取,以丙酮-正己烷(1:1, v/v)混合溶液为提取溶剂;提取液依次经由多层酸性硅胶柱和活化硅胶柱净化;洗脱液经氮吹浓缩至20 μL后,利用GC-MS/MS的多反应监测(MRM)模式进行定性和定量。结果表明本方法可对样品中的P26、P50和P62进行分析,相对标准偏差(RSD)小于11%,回收率可以达到55%～110%;P26、P50和P62的仪器检出限分别为3.0、3.0和6.0 pg。将该方法用于某地区农田表层土壤中3种指示性毒杀芬的检测,其中P26的含量为0.17 ng/g、P50为0.08 ng/g、P62为0.09 ng/g。此方法适用于土壤样品中指示性毒杀芬的分析。     

Compound‐specific bromine isotope analysis of brominated diphenyl ethers using gas chromatography multiple collector/inductively coupled plasma mass spectrometry

The bromine isotope composition is potentially diagnostic in both degradation monitoring and source apportionment of organobromines in the environment. A method for compound‐specific bromine isotope analysis (δ⁸¹Br) based on gas chromatography multiple collector inductively coupled plasma mass spectrometry (GC/ICPMS) was developed for common brominated diaromatic compounds. Brominated diphenyl ethers (BDEs) in Bromkal 70‐5DE, a technical flame‐retardant mixture containing mainly BDEs #47, #99 and #100, were used as test substances, with standard bracketing for the samples achieved through co‐injected monobromobenzene (MBB) with a known δ⁸¹Br of ?0.39‰ vs. Standard Mean Ocean Bromine (SMOBr). Three different heated transfer lines were constructed and tested to achieve efficient conduction of the BDEs from the gas chromatograph to the ICPMS instrument. The MBB was analyzed with a precision of 0.4‰ (1 s, n = 18). The precision for BDEs was 1.4–1.8‰ (1 s, n = 10–12 depending on the congener). The lower precision for the BDEs than for MBB may reflect the heat required to prevent condensation of the analytes in ICP torch assembly. The use of an internal standard of similar chemical structure to the analytes alleviates this problem, as illustrated by a difference of 0.3 ± 0.7‰ (1 s, n = 6) between the δ⁸¹Br values of co‐injected methoxy BDE‐47 and BDE‐47 extracted from whale blubber. Improvements in precision and accuracy may be achieved by the use of a more efficient heating of the torch assembly in conjunction with a set of internal standards that match the target compounds. Copyright © 2010 John Wiley & Sons, Ltd.     

Pesticide trace analysis using solid-phase extraction and gas chromatography with electron-capture and tandem mass spectrometric detection in water samples

Gas chromatography (GC) with electron-capture detection (ECD), mass spectrometry (MS) and tandem mass spectrometry (MS-MS) were employed for the identification of 12 pesticides in water samples. For this purpose, a solid-phase extraction procedure with C18 cartridges was used, optimising the breakthrough volume and the saturation concentration. In GC-MS-MS, the lowest detectable concentrations for the pesticides were between 2 and 26 ng l(-1), recoveries ranged from 70 to 133% in water samples spiked at 100 ng l(-1) and the relative standard deviations were in the range 5.3 to 17.4%. The proposed analytical methodology was applied to analyse pesticides in wetland samples from Almería (Spain).     

Evaluation of matrix solid‐phase dispersion extraction for the determination of polycyclic aromatic hydrocarbons in household dust with the aid of experimental design and response surface methodology

A simple, fast, and inexpensive procedure for sample preparation based on matrix solid‐phase dispersion was developed for the determination of Environmental Protection Agency 16 priority polycyclic aromatic hydrocarbons in indoor dust samples. Parameters that affect the extraction efficiency such as type of dispersant, elution solvent, and solvent volume were evaluated and optimized with the aid of experimental design and response surface methodology. Analysis was performed by HPLC coupled with UV‐Vis diode array detector (UV‐DAD). For verification, a GC coupled with a mass spectrometer in SIM mode was also applied. Recoveries obtained were from 53 to 120% for all target analytes with detection limits ranging from 0.2 to 10 ng/g and 0.2 to 2 ng/g for LC‐UV‐DAD and GC‐MS, respectively. The optimized method was used for the analysis of 11 household dust samples collected from private houses.     

气相色谱/离子阱串联质谱法检测大气中的多溴二苯醚

运用气相色谱-离子阱质谱(ion trap mass spectrometry,ITMS)建立了大气中8种多溴二苯醚的二级质谱(MS/MS)检测方法。优化后的MS/MS方法对7种三溴至七溴二苯醚(BDE28、-47、-99、-100、-153、-154、-183)和十溴二苯醚(BDE209)的仪器检出限分别为0.04~0.23 pg和9.38 pg;方法检出限为6.0~27.1 pg/m3和211.6 pg/m3;6点标准曲线相关系数(r)为0.9980~0.9999。方法对8种目标物的加标回收率为79.1%~101.0%,相对标准偏差(RSD)为4.3%~14.3%(n=6)。对6份南京实际大气样品的检测结果表明:离子阱质谱的选择反应监测(selected reaction monitoring,SRM)技术能有效的降低背景干扰。优化后的MS/MS方法对目标化合物有较高的灵敏度,可应用于大气中痕量多溴二苯醚的定量检测。