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1.
Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOFMS) was applied for the identification of four new photodegradation products of triclosan, a major antimicrobial agent used in personal care products. Wastewater samples, spiked at 7 microg/mL with triclosan, were irradiated with natural sunlight in order to generate the photodegradation products. Aliquots of the spiked water samples were taken at different times of irradiation and compounds were isolated from the water samples by solid-phase extraction. Separation and detection of the compounds and degradation products were accomplished by LC/TOFMS, which provided highly selective information about elemental compositions. Accurate mass measurements for the four degradation products permitted postulation of proposed empirical formulae in this study. Replacement of chlorine atoms by hydroxyl groups and chlorine losses are the major degradation pathways proposed. The degradation products were formed also under environmental conditions in wastewater matrices, thus suggesting their presence in real wastewater treatment processes.  相似文献   

2.
Results are reported for a comparative photodegradation study of atrazine and desethylatrazine in water using TiO2/H2O2, FeCl3/H2O2, and photolysis. Deionized water and ground water spiked with atrazine or desethylatrazine at 36 micrograms/L were irradiated by using a xenon arc lamp and/or sunlight. After irradiation, the water samples containing the spiked pesticides were preconcentrated by using C18 solid-phase extraction disks and analyzed by gas chromatography with nitrogen-phosphorus and mass spectrometric detection. A relative percentage of 7% desethylatrazine was detected in samples removed after 20 and 4 min of sensitized photodegradation with TiO2 and Fe3+, respectively. Atrazine and desethylatrazine did not degrade when solar irradiation (in winter) and deionized water were used. Atrazine degraded faster than desethylatrazine when a xenon arc lamp or sunlight plus FeCl3 was used, with half-lives varying from 5 to 11 min and from 19 to 26 min, respectively. In other photodegradation experiments, the degradation of atrazine was slightly higher than that of desethylatrazine. This study shows that desethylatrazine has slightly higher stability than atrazine in environmental water samples; this stability accounts for the frequent detection of desethylatrazine together with atrazine in natural waters.  相似文献   

3.
Determination of polybrominated diphenyl ethers (PBDEs) in environmental samples has raised great concerns due to the widespread use of PBDEs and their potential risk to humans. Solid-phase microextraction (SPME) is a fast, simple, cost-effective, and green sample preparation technique and is widely used for environmental analysis, but reports on the application of SPME for determination of PBDEs are very limited, and only a few publications dealing with commercial SPME fibers are available for extraction of PBDEs. Herein, we report a novel SPME method using multiwalled carbon nanotubes (MWCNTs) as the SPME fiber coating for gas chromatography with electron-capture detection (GC-ECD) of PBDEs in environmental samples. The MWCNTs coating gave much higher enhancement factors (616-1756) than poly (5% dibenzene-95% dimethylsiloxane) coating (139-384) and activated carbon coating (193-423). Thirty-minute extraction of 10 mL of sample solution using the MWCNTs coated fiber for GC-ECD determination yielded the limits of detection of 3.6-8.6 ng L(-1) and exhibited good linearity of the calibration functions (r(2)>0.995). The precision (RSD%, n=4) for peak area and retention time at the 500 ng L(-1) level was 6.9-8.8% and 0.6-0.9%, respectively. The developed method was successfully applied for the analysis of real samples including local river water, wastewater, and milk samples. The recovery of the PBDEs at 500 ng L(-1) spiked in these samples ranged from 90 to 119%. No PBDEs were detected in the river water and skimmed milk samples, whereas in the wastewater sample, 134-215 ng L(-1) of PBDEs were found. The PBDEs were detected in all whole fat milk samples, ranging from 13 to 484 ng L(-1). In a semiskimmed milk sample, only BDE-47 was found at 21 ng L(-1).  相似文献   

4.
Abstract

A photodegradation study for Irgarol was carried out in order to investigate several products of degradation formed in different environmental matrices and under different conditions. Deionized water, groundwater and seawater samples, spiked at 30–100 μg/L with Irgarol, were irradiated using a xenon are lamp and/or sunlight. Aliquots of the spiked water samples were taken at different times of irradiation and compounds were isolated from the water samples by means of solid-phase extraction (SPE) using either C18 or PLRP-s cartridges. Separation and detection of the compounds was accomplished by several analytical methodologies such as liquid chromatography-diode array detection (LC-DAD), liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI/MS) and gas chromatography-mass spectrometry (GC-MS). Four new byproducts, with molecular weights of 167, 197, 207 and 213, were identified in this photodegradation study. When the photolysis was carried out with xenon lamp, half-lives of Irgarol were 103.8, 125.4 and 107.5 minutes in deionized water, groundwater and seawater, respectively. In seawater samples, a 98% of degradation was observed for Irgarol, after 217 hours of solar irradiation, being the main byproduct formed that corresponding to Mw = 213. On the other hand, the use of two different sensitizers -(TiO2/H2O2), (FeCI3/H2O2)- was also evaluated in deionized water samples containing Irgarol. These experiments were carried out in order to evaluate the use of these two sensitizers for decontamination of polluted waters.  相似文献   

5.
In this study, the photoinduced degradation of five polybrominated diphenyl ethers (PBDEs), BDE-47, BDE-100, BDE-99, BDE-154 and BDE-153, is studied using solid-phase microextraction polydimethylsiloxane fibers as photolytic support. PBDEs are extracted from aqueous solutions using SPME fibers that are subsequently exposed to UV irradiation for different times (from 2 to 60 min). Photodegradation kinetics of the five PBDEs, tentative identification and photochemical behavior of the generated photoproducts, as well as photodegradation pathways, have been studied employing this on-fiber approach technique (photo-SPME) followed by gas chromatography-mass spectrometry analysis. Aqueous photodegradation studies have also been performed and compared with photo-SPME. All the photoproducts detected in the aqueous experiments were previously found in the photo-SPME experiments. In this study, reductive debromination by successive losses of bromine atoms is confirmed as the main photodegradation pathway of PBDEs. A large number of PBDEs were obtained as photoproducts of the five target analytes. Other mechanism of photodegradation observed was intramolecular cyclization from the homolytic dissociation of the C-Br bond; thus, polybromo-dibenzofurans were generated. This work contributes to the study of the photodegradation of PBDEs and shows the potential of photo-SPME to evaluate the photo-transformation of organic pollutants.  相似文献   

6.
In this study, we present a simple and easy-to-use extraction method that is based on a hollow-fiber microporous membrane liquid-liquid extraction (HF-MMLLE), as an extraction technique, followed by gas chromatography-mass spectrometry (GC-MS) to determine a group of brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), at trace levels in aqueous samples. The hollow-fiber membrane (HF) filled with organic solvent was immersed into the aqueous sample, spiked with the analytes at ng l(-1) level, and stirred for 60 min. The proposed method could attain enrichment factors (E(e)) up to 5200 times, after optimising parameters, such as organic solvent, stirring speed and extraction time, that affect the extraction. The HF-MMLLE-GC-MS method was successfully applied to the extraction of PBDEs from tap, river and leachate water samples with spike recoveries ranging from 85% to 110%. The method validation with reagent and leachate water samples provided good linearity, detection limits of 1.1 ng l(-1) or lower, both in reagent and leachate water, as well as satisfactory precision in terms of repeatability and reproducibility with values of % relative standard deviation (%RSD) lower than 8.6 and 16.9, respectively.  相似文献   

7.
A degradation study of two phenoxy acid [(2,4-dichlorophenoxy) propanoic acid and (2,4,5-trichlorophenoxy) acetic acid] and two phenylurea (diuron and monolinuron) herbicides, spiked at 50 ppb in water, was performed. Some samples were subjected to neutral and basic hydrolysis; other samples were subjected to photolysis using either sunlight or a xenon arc lamp. After degradation, the water samples were preconcentrated using solid-phase extraction (SPE) with Carbopack B columns and analysed by a micellar electrokinetic capillary chromatography (MECC) system with UV detection at 210 nm. Phenoxyacetic acids were not degraded neither by hydrolysis nor by sunlight photolysis, but they were photodegraded when they were exposed to a xenon arc lamp, with half-lives around 300 min. Phenylurea herbicides were hydrolysed at the two-tested pH, with half-lives varying from 25 to 290 days. The main hydrolysis products were the corresponding chloroanilines. Diuron and monolinuron were also degraded when they were exposed to sunlight and xenon arc lamp. The main photodegradation pathway for diuron corresponded to dehalogenation, while for monolinuron dealkylation and hydroxylation were also postulated. The toxicity of the studied herbicides and their degradation products was evaluated by means of Microtox tests. The obtained results indicated that the toxicity of the degraded samples was higher than the toxicity of the herbicides.  相似文献   

8.
The suitability of an inexpensive polydimethysiloxane (PDMS) sorbent, produced on an industrial scale, for the extraction of polybrominated diphenyl ethers (PBDEs), from tetra- to hexabrominated congeners, from water samples was assessed. Experiments were carried out using samples spiked with a pentabromo diphenyl ether (pentaBDE) mixture, PDMS rods with a diameter of 2 mm and gas chromatography with micro-electron-capture detection (GC-micro-ECD). Influence of several variables on the efficiency of the enrichment step and the further desorption of the analytes was investigated in detail. The best performance was achieved in the headspace sorptive extraction (HSSE) mode, at 95 degrees C, using 80 mL water samples containing a 30% of sodium chloride. Extractions were performed overnight using disposable PDMS rods with a length of 10 mm (31 microL volume). Analytes were further recovered from the PDMS sorbent using just 1 mL of diethyl ether. This solvent was evaporated and extracts reconstituted with 25 microL of isooctane. Under final working conditions absolute extraction efficiencies from 69 to 93% and enrichment factors higher than 2200 folds were achieved for all species. The proposed method provided acceptable precisions (relative standard deviations values under 12%), correlation coefficients higher than 0.998 and the yield of the HSSE process remained constant for different water samples.  相似文献   

9.
Solid-phase microextraction (SPME) is an effective technique for the extraction of polybrominated diphenyl ethers (PBDEs) from environmental water samples. Although it has been also applied to sediments, the organic content of this matrix causes an exponential decrease in the yield of the extraction. This work presents an improved SPME procedure for the sensitive determination of six PBDEs (tetra- to hexa-brominated congeners) in sediments containing up to 6% of total organic carbon (TOC). Samples (0.25–0.5 g) were accurately weighed in 22 mL glass vessels, mixed with a given amount of potassium permanganate, 0.5 mL of sulphuric acid and 5 mL of water. Extractions were performed at 100 °C, for 40 min, using a polyacrylate (PA) coated fibre in the headspace (HS) mode. Potassium permanganate showed a dramatic, positive effect on the yield of the extraction. Its optimum amount was related to the TOC of the sediment, with overall highest responses attained for 40 mg of oxidant per mg of organic carbon in the SPME vessel. Under final working conditions, the combination of SPME with gas chromatography coupled to tandem mass spectrometry (GC–MS/MS) provided relative standard deviations (RSDs) below 14%, relative recoveries from 76 to 111% and limits of quantification (LOQs) lower than 0.15 ng g−1 for all the investigated PBDEs in spiked river and marine sediments with different TOC. The performance of the method was also evaluated satisfactorily with a medium complexity (TOC 6.7%), real-life polluted sediment, previously analyzed in inter-laboratory comparison exercises.  相似文献   

10.
The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEOx and CnEOx) was investigated in different waters with and without a photoinducter (Fe(III)). Deionized water and industrial effluent spiked at 0.5 mg/L with C10EO6 and NPEO9 were irradiated using a xenon arc lamp. Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C18 cartridges. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants. The intermediates detected included nonylphenol diethoxylate (NPEO2) and nonylphenol ethoxy acetic acid (NPE2C). Much smaller amounts of degradation products of NPEO9 having only the alkyl chain carboxylated were also formed in the photocatalysis experiment. The identified C10EO6 photoproducts included fatty alcohols and acids. Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C10EO6 and the deethoxylation of NPEO9. The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t(1/2)) of C10EO6, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO9, 17 h and 14 h in deionized water and wastewater, respectively. When induced photodegradation was undertaken, the t(1/2) for NPEO9 was 21 min and 29 min in deionized water and wastewater, respectively. Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis.  相似文献   

11.
A novel and efficient analytical methodology is proposed for extracting and preconcentrating polybrominated diphenyl ethers (PBDEs) from samples of environmental interest prior gas chromatography–mass spectrometry (GC–MS) analysis. It is based on the induction of micellar organized medium by using a non-ionic surfactant (Triton X-114) to extract the target PBDEs. To enable coupling the efficient extracting technique with GC analysis, ultrasound-assisted back-extraction (UABE) into an organic solvent was required. Several factors, including surfactant type and concentration, equilibration temperature and time, ionic strength, pH and buffers nature and concentration were studied and optimized over the extraction efficiency of the proposed technique. Under optimal experimental conditions, the target analytes were quantitatively extracted achieving an enrichment factor of 250 when 10 mL aliquot of ultrapure water spiked with PBDE-standard mixture (10 pg mL−1 each PBDE) was extracted. Method detection limits (MDLs) calculated with aqueous PBDEs solutions as three times the signal-to-noise ratio (S/N), ranged from 1 to 2 pg mL−1 with RSDs values ≤8.5% (n = 5). The coefficients of estimation of the calibration curves obtained following the proposed methodology were ≥0.9987 and linear range of all PBDEs was 4–150 pg mL−1. The proposed methodology was validated by carrying out a recovery study by spiking the samples at two different concentration levels of PBDEs (10 and 50 pg mL−1 for waters samples). Recoveries values in the range of 96–106% for water samples were obtained showing satisfactory robustness of the method for analyzing PBDEs in water samples. The proposed methodology was applied for the analysis of PBDEs: 2,2′,4,4′-tetraBDE (BDE-47), 2,2′,4,4,5-pentaBDE (BDE-99), 2,2′,4,4,6-pentaBDE (BDE-100) and 2,2,4,4′,5,5′-hexaBDE (BDE-153) in water samples, including drinking, lake, river water and soil samples. Significant quantities of PBDEs were not found in the analyzed samples.  相似文献   

12.
鱼肉组织中多溴联苯醚的定量分析   总被引:9,自引:0,他引:9  
多溴联苯醚(PBDEs)是一类广泛用于家用电器、电子产品、塑料泡沫、家居装饰材料等行业的添加型阻燃剂[1],使用量最多的是五溴联苯醚(penta-BDE),八溴联苯醚(octa-BDE)和十溴联苯醚(deca-BDE)3种[2]。最近的研究表明[4-6],多溴联苯醚已广泛地存在于各种环境介质、生物体及人体中  相似文献   

13.
del Olmo M  Zafra A  Jurado AB  Vilchez JL 《Talanta》2000,50(6):1141-1148
Bisphenol A (BPA) in the presence of phenol is determined using a method based on first-derivative spectrofluorimetry. The proposed method involves a micro liquid–liquid extraction of sodium chloride saturated water samples with diethyl ether followed by direct fluorimetric analysis of extracts. The excitation spectra of both compounds in diethyl ether are recorded between 200 and 290 nm, with the emission wavelength at 306 nm. The first-derivative spectra were calculated, measuring the analytical signal for BPA at 239 nm. The concentration range over which the method was applied was 0.5–10.0 μg·l−1 of BPA with relative standard deviations of 2.9% for a concentration of 4.0 μg·l−1 of BPA. The detection limit was 0.07 μg·l−1. The proposed method was applied satisfactorily to the determination of BPA in synthetic mixtures and water samples from different sources previously spiked with different amounts of these chemicals. Recovery values ranging from 93% to 112% were obtained for water samples.  相似文献   

14.
Xiao Z  Feng J  Shi Z  Li J  Zhao Y  Wu Y 《色谱》2011,29(12):1165-1172
建立了固相萃取同时提取、净化血清中四溴双酚A(TBBPA)、α, β, γ-六溴环十二烷(HBCD)和8种多溴联苯醚(PBDEs)同系物的样本前处理方法,并结合色谱-质谱分离分析技术检测人血清样本中该类化合物的含量。试样在加入各自的同位素内标物后以甲基叔丁基醚/正己烷(1:1, v/v)混合溶剂进行萃取,再经浓硫酸去除脂肪后,以LC-Si固相萃取柱分离HBCD/TBBPA和PBDEs。采用分步检测的方式,在50 mm长BEH C18反相色谱柱上以超高效液相色谱-串联质谱(UPLC-MS/MS)的多反应监测模式(MRM)检测HBCD和TBBPA,在15 m长的毛细管柱上以气相色谱-负化学源质谱(GC-NCI/MS)的选择离子监测模式(SIM)检测PBDEs。以胎牛血清为空白基质,当HBCD、TBBPA和BDE-209的加标水平为0.5 ng/g和5 ng/g、三溴至七溴联苯醚的加标水平为0.05 ng/g和0.5 ng/g时,它们的平均加标回收率为80.3%~108.8%,相对标准偏差为1.02%~11.42%(n=5);以信噪比(S/N)为3计算,方法的检出限(LOD)为1.81~42.16 pg/g。采用该方法对实际样品进行测定,结果表明,本方法快速、准确、灵敏度高,能够满足血清中HBCD、TBBPA和PBDEs残留的同时提取及测定的要求。  相似文献   

15.
A gas chromatography electron capture negative ionization mass spectrometry (GC(ECNI)MS) procedure for the determination of priority polybrominated diphenyl ethers (PBDEs; congeners 28, 47, 99, 100, 153 and 154) in water samples at regulatory EU levels has been developed. The method is based on the use of 81Br-labelled PBDEs for isotope dilution analysis and the measurement of 79Br/81Br isotope ratios in gas chromatography peaks with the electron capture negative ionization technique. The suitability of this ion source for the precise and accurate measurement of bromine isotope ratios has been demonstrated. The general ECNI-IDMS procedure was evaluated by the analysis of NIST SRM 1947 (Lake Michigan fish tissue) with satisfactory results. For the analysis of water samples, 500 mL of the samples were spiked with the labelled PBDEs and extracted with 10 mL isooctane for 30 min. The extract was evaporated down to ca. 100 μL and injected in the GC(ECNI)MS. Detection limits ranged from 0.014 −1 to 0.089 pg mL−1 depending on the congener. Recoveries from real water samples, spiked at a level of 0.5 pg mL−1, ranged from 77% to 102%.  相似文献   

16.
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。  相似文献   

17.
A method based on liquid chromatography/mass spectroscopy with electrospray ionization in positive mode (LC/ESI-MS) to determine trace levels of pyrethroids in environmental water samples has been developed. The chromatographic and the MS parameters were optimized to obtain the best sensitivity and selectivity for all pesticides. Solid-phase extraction (SPE) using C18 cartridges was applied for preconcentration of pesticide trace levels (ng/L) in both ground and sea water samples. The preconcentration step was carried out with 800 mL of water sample modified with 200 mL of MeOH to improve the recovery percentages in the SPE procedure. The SPE-LC/ESI-MS methodology was applied to determine pyrethroids in ground and sea water samples spiked at ng/L concentration levels. Recoveries obtained in ground water were satisfactory (between 72 and 110%). However, an enhancement of the signals of all pesticides in the sea water was found due to the negative effect of the salt in the ionization source. To eliminate this effect a simple cleanup step of the SPE cartridge using 200 mL of Milli-Q water was performed. The cleanup removed the matrix effect completely from the marine samples. Thus, the recovery percentages ranged from 80 to 115%. The method was applied to determine ng/L of pyrethroids in both ground and marine water samples with precision values lower than 10%.  相似文献   

18.
A new and fast method for the determination of priority phenols in marine sediment samples by high-performance liquid chromatography using microwave-assisted micellar extraction is optimized. This study is carried out using the nonionic surfactants polyoxyethylene 9 lauryl ether (polidocanol) and genapol X-080 as extractants. Parameters studied include surfactant concentration, solution pH, extraction time, and power. Once the method is optimized, it is applied to different spiked marine sediments from of the Canary Islands coastlines (Spain). The results obtained indicate that a power irradiation of 500 W for 2 min achieved the best extraction efficiency (approximately 100% recovery) and less than 10% relative standard deviation. Detection limits are obtained in the 2-20 microg/g range for the phenols studied. Finally, the proposed method provides a simple, fast, and organic solvent-free procedure to analyze phenols from marine sediment samples.  相似文献   

19.
Shi Z  Wang Y  Feng J  Huang P  Wu Y 《色谱》2011,29(6):543-548
建立了凝胶渗透色谱(GPC)结合气相色谱-负化学源质谱(GC-NCI/MS)检测鱼肉及鱼油中8种多溴联苯醚(PBDEs)同系物及2种得克隆阻燃剂(DP)的分析方法。试样中加入内标物BDE-77和13C12-BDE-209后进行索氏提取,提取液经自动GPC系统除脂,多层硅胶层析柱净化后,在15 m长的毛细管气相色谱柱上分离,NCI/MS以选择离子监测方式检测目标化合物。以鱼肉样品为基质,当PBDEs的加标水平为0.2 ng/g和2 ng/g、BDE-209和DP的加标水平相应提高10倍时,其平均加标回收率为71.1%~121.4%,相对标准偏差为2.96%~13.31%(n=5);以信噪比(S/N)为3计算方法的检出限(LOD)为2.2~39.8 ng/kg。用该方法检测市售鱼肉及鱼油样品,其中多溴联苯醚总含量为2.18~15.93 ng/g,以BDE-209、BDE-47为主,两种DP均未检出。该方法准确、灵敏度高,能够满足富含脂质的动物性样品中痕量DP和PBDEs残留的分析要求。  相似文献   

20.
Cai Z  Jiang G 《Talanta》2006,70(1):88-90
Soil samples collected from an electronic waste recycling site were prepared by using Soxhlet extraction and multiple-step column chromatographic clean-up. Gas chromatography/ion trap mass spectrometry method was developed to determine polybrominated diphenyl ethers (PBDEs) in the sample extracts. The method performance was evaluated by the recovery of 13C-labeled internal standards and by analyzing quality assurance and quality control samples. Relative error and relative standard deviation obtained from the analysis of duplicated samples and spiked matrix were better than 10%. PBDEs were detected in the field soil samples collected from an e-wastes disposal site at levels from low parts-per-billions to 600 parts-per-billions.  相似文献   

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