多壁纳米碳管固相萃取测定水中的有机氯农药

对于水样中的有机氯农药的净化方法主要是采用传统的液液分配的方法,缺点是溶剂使用量和前处理复杂。近年来固相萃取及固相微萃取等技术被应用到水样中的有机污染物的测定。如利用键合在硅胶上的非极性(C18,LC18等)或极性物质(LC-CN,LC-NH2)对水中有机物进行富集,用GDX或XAD自填的固相柱的报道也很多。纳米技术和纳米材料的发展为开发固相萃取材料带来新契机。纳米材料是指尺寸大小在从1～100m之间物质。与普通的块体材料相比,纳米材料具有较大的比表面,因而有可能具有较大吸附容量。纳米材料在环境有机污染物分离富集方面的应用研究才刚刚开始。本文主要就纳米碳管对水样中的有机氯农药进行研究,优化固相萃取条件。     

Bamboo Charcoal as Solid-Phase Extraction Adsorbent for the Determination of Organophosphorus Pesticides in Water Samples by High-Performance Liquid Chromatography

In this paper, bamboo charcoal was successfully developed for the solid-phase extraction adsorbent for the determination of six organophosphorus pesticides in water samples. After the bamboo charcoal was pretreated and packed in the solid-phase extraction cartridge, the organophosphorus pesticides in water samples were carried out the solid-phase extraction. To establish a perfect solid-phase extraction procedure, the experimental conditions including the eluent, eluent volume, pH of the sample, flow rate of the sample, and loading volume of the sample were all investigated. When 100 mL water samples in the pH range of 6–7 were loaded with the flow rate of 2.5 mL · min^?1 and then eluted with 10 mL acetonitrile, the proposed extraction method was validated by the recovery, correlation coefficient (R²), repeatability (RSD, n = 7) and LODs, which were 69.6–93.4%, 0.9982–0.9998, 2.9–5.6%, and 0.08–1.04 µg · L^?1, respectively. Furthermore, the analysis of the tap, snow, and river water samples demonstrated the feasibility of the proposed SPE method for real water samples. Based on the aforementioned factors, it could be concluded that bamboo charcoal was a good solid-phase extraction adsorbent, and this proposed solid-phase extraction method was suitable for the effective enrichment and determination of the organophosphorus pesticides in water samples.     

基于PA6纳米纤维膜固相萃取-液相色谱法检测牛奶中的邻苯二甲酸酯

采用静电纺丝法制备了聚酰胺6(PA6)纳米纤维膜, 结合固相萃取技术-液相色谱法(HPLC-UV)检测了市售牛奶样品中的6种邻苯二甲酸酯(PAEs)的含量. 对影响实验的各种因素, 如提取溶剂的种类及用量、超声时间、洗脱溶剂的种类及用量、纳米纤维膜的用量、pH及过样速度等进行了考察. 在最优化条件下, 邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸丁基苄酯(BBP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己)酯(DEHP)和邻苯二甲酸二正辛酯(DOP)的检出限分别为0.02, 0.01, 0.05, 0.05, 0.10和0.25 ng/mL. 将该方法应用于不同品牌不同包装牛奶样品的检测, 只需2.5 mg PA6纳米纤维膜, 即可完全萃取样品中的PAEs, 相对标准偏差(RSD)小于5.82%, 回收率为93.40%~104.83%. 该方法测定牛奶中PAEs环境雌激素, 检出限低, 灵敏度高, 结果准确可靠, 重现性好.     

Bamboo charcoal as a novel solid-phase microextraction coating material for enrichment and determination of eleven phthalate esters in environmental water samples

This study demonstrates the potential of bamboo charcoal as a novel and inexpensive solid-phase microextraction (SPME) coating material for enrichment and determination of organic pollutants in water samples. Bamboo charcoal was prepared and used as a SPME coating material. Eleven phthalate esters (PAEs) were used as model analytes, and gas chromatography–mass spectrometry was used for separation and detection. Important extraction conditions (ionic strength, stirring rate, and extraction time) and desorption conditions (desorption temperature and time) were systematically investigated and optimized. Linearity of 0.1–100 μg?L^?1 and correlation coefficients of 0.9992–0.9998 were obtained under optimum conditions. Inter-day and intra-day repeatability were 2.15–9.93 % and 1.89–9.85 %, respectively, and fiber-to-fiber reproducibility was 5.42–9.66 %. On the basis of a chromatographic signal-to-baseline noise ratio of three, the limits of detection reached 0.004–0.023 μg?L^?1. Satisfactory results were achieved when the bamboo coating was used for determination of 11 PAEs in real water samples. The experimental results indicate that bamboo charcoal has significant potential as a SPME coating material for rapid enrichment and sensitive determination of organic pollutants in environmental samples.     

固相萃取-气相色谱法测定地下水中痕量酞酸酯的研究

本文建立了固相萃取-气相色谱法定量分析地下水中酞酸酯类（PAEs）有机污染物的方法。利用正交试验和单因素实验对影响回收率的4个主要因素（洗脱溶剂种类、水样体积、洗脱溶剂体积、固相萃取小柱填料量）进行了萃取条件的优化。综合考虑各方面因素后确定的最佳萃取条件为：二氯甲烷和丙酮为洗脱剂,体积8mL、0．5L水样、柱填料500mg。方法线性范围0．05～10．00μg／L,检出限0．05～0．341ng／L,相对标准偏差0．038％～1．107％。该方法应用于江汉平原地下水中PAEs测定,取得满意结果。     

Sensitive determination of amide herbicides in environmental water samples by a combination of solid‐phase extraction and dispersive liquid–liquid microextraction prior to GC–MS

In this paper, solid‐phase extraction (SPE) in combination with dispersive liquid–liquid microextraction (DLLME) has been developed as a sample pretreatment method with high enrichment factors for the sensitive determination of amide herbicides in water samples. In SPE–DLLME, amide herbicides were adsorbed quantitatively from a large volume of aqueous samples (100 mL) onto a multiwalled carbon nanotube adsorbent (100 mg). After elution of the target compounds from the adsorbent with acetone, the DLLME technique was performed on the resulting solution. Finally, the analytes in the extraction solvent were determined by gas chromatography–mass spectrometry. Some important extraction parameters, such as flow rate of sample, breakthrough volume, sample pH, type and volume of the elution solvent, as well as salt addition, were studied and optimized in detail. Under optimum conditions, high enrichment factors ranging from 6593 to 7873 were achieved in less than 10 min. There was linearity over the range of 0.01–10 μg/L with relative standard deviations of 2.6–8.7%. The limits of detection ranged from 0.002 to 0.006 μg/L. The proposed method was used for the analysis of water samples, and satisfactory results were achieved.     

Ultrasound-assisted Low Density Solvent Based Dispersive Liquid-liquid Microextraction for Determination of Phthalate Esters in Bottled Water Samples

A technique of ultrasound-assisted low density solvent based dispersive liquid-liquid microextraction was developed for the determination of four phthalate esters, including dimethyl phthalate(DMP), diethyl phthalate(DEP), di-n-butyl phthalate(DnBP) and di(2-ethylhexyl) phthalate(DEHP) in bottled water samples. A low density solvent, toluene, was selected as extraction solvent. In the extraction process, a mixture of 15 μL of toluene(extraction solvent) and 100 μL of methanol(disperser solvent) was rapidly injected into 1.0 mL of water samples. A cloudy solution was formed after ultrasounded for 5 min, and then centrifuged at 5000 r/min for 5 min. The enriched analytes in the floating phase were determined by means of gas chromatograph. Under the optimum conditions, the enrichment factors were found to be in a range of 29-67, and the recoveries were ranged from 81.2% to 103.9%. The limits of the detection were in a range of 3.8-5.6 μg/L. The proposed method was applied to the extraction and determination of phthalate esters in bottled water samples, and the concentrations of phthalate esters found in the water samples were below the allowable levels.     

Application of dispersive liquid-liquid microextraction and high-performance liquid chromatography for the determination of three phthalate esters in water samples

A novel method, dispersive liquid-liquid microextraction (DLLME) coupled with high-performance liquid chromatography-variable wavelength detector (HPLC-VWD), has been developed for the determination of three phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), and di-n-butyl phthalate (DnBP)) in water samples. A mixture of extraction solvent (41 μL carbon tetrachloride) and dispersive solvent (0.75 mL acetonitrile) were rapidly injected into 5.0 mL aqueous sample for the formation of cloudy solution, the analytes in the sample were extracted into the fine droplets of CCl₄. After extraction, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by HPLC-VWD. Some important parameters, such as the kind and volume of extraction solvent and dispersive solvent, extraction time and salt effect were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 5 to 5000 ng mL⁻¹ for target analytes. The enrichment factors for DMP, DEP and DnBP were 45, 92 and 196, respectively, and the limits of detection were 1.8, 0.88 and 0.64 ng mL⁻¹, respectively. The relative standard deviations (R.S.D.) for the extraction of 10 ng mL⁻¹ of phthalate esters were in the range of 4.3-5.9% (n = 7). Lake water, tap water and bottled mineral water samples were successfully analyzed using the proposed method.     

LC Determination of Phthalate Esters in Water Samples Using Continuous-Flow Microextraction

A novel method, continuous-flow microextraction (CFME) combined with liquid chromatography (LC) with variable-wavelength detector (VWD), has been developed for the determination of three phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), and di-n-butyl phthalate (DnBP)) in water samples. Experimental parameters including extraction solvent, solvent drop volume, flow rate of sample solution, extraction time and ionic strength, which affected the extraction efficiency, were studied and optimized. Under the optimum extraction conditions, the method yields a linear calibration curve in the concentration range of 10–10,000 ng mL^?1 for target analytes. The enrichment factors of this method for DMP, DEP and DnBP reached at 27, 44 and 20, respectively, and the detection limits were 2, 1 and 5 ng mL^?1, respectively. Good repeatability of extraction was obtained with relative standard deviations below 8.6%. The results demonstrated that CFME followed by LC-VWD is a simple and reliable technique for the determination of phthalate esters in water samples.     

Phytic acid induced three‐dimensional graphene for the enrichment of phthalate esters from bottled water and sports beverage samples

A three‐dimensional graphene was synthesized through a hydrothermal reaction of graphene oxide with phytic acid. The microstructure and morphology of the phytic acid induced three‐dimensional graphene were investigated by nitrogen adsorption–desorption isotherms, scanning electron microscopy, and transmission electron microscopy. With a large surface area and three‐dimensional structure, the graphene was used as the solid‐phase extraction adsorbent for the extraction of phthalate esters from bottled water and sports beverage samples before high‐performance liquid chromatographic analysis. The results indicated that the graphene was efficient for the solid‐phase extraction of phthalate esters. The limits of detection (S/N = 3) of the method for the analytes were 0.02–0.03 ng/mL for the water samples and 0.03–0.15 ng/mL for the sports beverage sample. The limits of quantitation (S/N = 9) for the analytes were 0.06–0.09 ng/mL for water samples and 0.09–0.45 ng/mL for sports beverage sample. The calibration curves for the phthalate esters by the method had a good linearity from 0.1 to 80.0 ng/mL with correlation coefficients larger than 0.9997. The recoveries of the analytes for the method fell in the range of 86.7–116.2% with the relative standard deviations between 1.5 and 6.8%.     

Development of dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry as a simple, rapid and highly sensitive method for the determination of phthalate esters in water samples

A simple, rapid and efficient method, the dispersive liquid-liquid microextraction (DLLME) in conjunction with gas chromatography-mass spectrometry (GC-MS), has been developed for the extraction and determination of phthalate esters (dimethyl phthalate, diallyl phthalate, di-n-butyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate and di-2-ethylhexyl phthalate) in water samples. Factors relevant to the microextraction efficiency, such as the kind of extraction, the disperser solvent and their volume, the salt effect and the extraction time were investigated and optimized. Under the optimized extraction conditions (extraction solvent: chlorobenzene, volume, 9.5microL; disperser solvent: acetone, volume, 0.50mL, without salt addition and extraction time below 5s), the figures of merit of the proposed method were evaluated. The values of the detection limit of the method were in the range of 0.002-0.008microgL(-1), while the RSD% value for the analysis of 1microgL(-1) of the analytes was below 6.8% (n=4). A good linearity (0.9962>/=r(2)>/=0.9901) and a broad linear range (0.02-100microgL(-1)) were obtained. The method exhibited enrichment factors and recoveries, ranging from 681 to 889 and 68.1 to 88.9%, respectively, at room temperature (25+/-1 degrees C). Finally, the proposed method was successfully utilized for the preconcentration and determination of the phthalate esters in different real water samples and satisfactory results were obtained.     

Magnetic nanoporous carbon as an adsorbent for the extraction of phthalate esters in environmental water and aloe juice samples

In this work, magnetic nanoporous carbon with high surface area and ordered structure was synthesized using cheap commercial silica gel as template and sucrose as the carbon source. The prepared magnetic nanoporous carbon was firstly used as an adsorbent for the extraction of phthalate esters, including diethyl phthalate, diallyl phthalate, and di‐n‐propyl‐phthalate, from lake water and aloe juice samples. Several parameters that could affect the extraction efficiency were optimized. Under the optimum conditions, the limit of detection of the method (S/N = 3) was 0.10 ng/mL for water sample and 0.20 ng/mL for aloe juice sample. The linearity was observed over the concentration range of 0.50–150.0 and 1.0–200.0 ng/mL for water and aloe juice samples, respectively. The results showed that the magnetic nanoporous carbon has a high adsorptive capability toward the target phthalate esters in water and aloe juice samples.     

Macrocyclic polyamine‐functionalized silica as a solid‐phase extraction material coupled with ionic liquid dispersive liquid–liquid extraction for the enrichment of polycyclic aromatic hydrocarbons

In this study, silica modified with a 30‐membered macrocyclic polyamine was synthesized and first used as an adsorbent material in SPE. The SPE was further combined with ionic liquid (IL) dispersive liquid–liquid microextraction (DLLME). Five polycyclic aromatic hydrocarbons were employed as model analytes to evaluate the extraction procedure and were determined by HPLC combined with UV/Vis detection. Acetone was used as the elution solvent in SPE as well as the dispersive solvent in DLLME. The enrichment of analytes was achieved using the 1,3‐dibutylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL/acetone/water system. Experimental conditions for the overall macrocycle‐SPE–IL‐DLLME method, such as the amount of adsorbent, sample solution volume, sample solution pH, type of elution solvent as well as addition of salt, were studied and optimized. The developed method could be successfully applied to the analysis of four real water samples. The macrocyclic polyamine offered higher extraction efficiency for analytes compared with commercially available C₁₈ cartridge, and the developed method provided higher enrichment factors (2768–5409) for model analytes compared with the single DLLME. Good linearity with the correlation coefficients ranging from 0.9983 to 0.9999 and LODs as low as 0.002 μg/L were obtained in the proposed method.     

Preconcentration and sensitive determination of hexabromocyclododecane diastereomers in environmental water samples using solid phase extraction with bamboo charcoal cartridge prior to rapid resolution liquid chromatography-electrospray tandem mass spectrometry

In this paper, a simple and cheap method for the simultaneous preconcentration and sensitive determination of three hexabromocyclododecane (HBCD) diastereomers (α-, β-, and γ-HBCD) in environmental water samples has been developed. It was based on solid phase extraction (SPE) and rapid resolution liquid chromatography-electrospray tandem mass spectrometry. Bamboo charcoal, one kind of cheap material, was investigated and used as SPE adsorbent for the enrichment and determination of HBCD diastereomers. Related important parameters affecting extraction efficiencies, including type and volume of eluant, amount of sorbent, sample pH, flow rate, and sample volume, were investigated and optimized in detail. Under the optimum conditions, experimental data exhibited excellent linear relationships between peak area and concentrations over the range 0.1-10?μg?L(-1). The limits of detection and precision were in the range of 0.005-0.015?μg?L(-1) and 4.59-7.47%, respectively. The proposed method has been successfully applied for the trace analysis of HBCD diastereomers in real-world environmental water samples.     

Highly sensitive determination of tetrabromobisphenol A and bisphenol A in environmental water samples by solid‐phase extraction and liquid chromatography‐tandem mass spectrometry

Using bamboo‐activated charcoal as SPE adsorbent, a novel SPE method was developed for the sensitive determination of tetrabromobisphenol A and bisphenol A in environmental water samples by rapid‐resolution LC‐ESI‐MS/MS. Important parameters influencing extraction efficiency, including type of eluent, eluent volume, sample pH, volume and flow rate, were investigated and optimized. Under the optimal extraction conditions (eluent: 8 mL methanol, pH: 7; flow rate: 4 mL/min; sample volume: 100 mL), low LODs (0.01–0.02 ng/mL), good repeatability (6.2–8.3%) and wide linearity range (0.10–10 ng/mL) were obtained. Satisfied results were achieved when the proposed method was applied to determine the two target compounds in real‐world environmental water samples with spiked recoveries over the range of 80.5–119.8%. All these facts indicate that trace determination of tetrabromobisphenol A and bisphenol A in real‐world environmental water samples can be realized by bamboo‐activated charcoal SPE‐rapid resolution‐LC‐ESI‐MS/MS.     

Determination of trace triclosan in environmental water by microporous bamboo‐activated charcoal solid‐phase extraction combined with HPLC‐ESI‐MS

A sensitive and efficient analytical method for triclosan (TCS) determination in water, which involves enrichment with bamboo‐activated charcoal and detection with HPLC‐ESI‐MS, was developed. The influence of several operational parameters, including the eluant and its volume, the flow rate, the volume andacidity of the sample, and the amount of bamboo‐activated charcoal, were investigated and optimized. Under the optimum conditions, linearity of the method was observed in the range of 0.02–20 μg/L, with correlation coefficients (r²) >0.9990. The limit of detection was 0.002 μg/L based on the ratio of chromatographic signal to baseline noise (S/N = 3). The spiked recoveries of TCS in real water samples were achieved in the range of 97.6–112.5%. The proposed method was applied to analyze TCS in real aqueous samples. All the surface water samples collected in Xiaoqing River had detectable levels of TCS with concentrations of 42–197 ng/L.     

Porous carbon derived from a metal–organic framework as an efficient adsorbent for the solid‐phase extraction of phthalate esters

A porous carbon designated as MOF‐5‐C was prepared by directly carbonizing a metal–organic framework (MOF‐5). The morphology and microstructure of MOF‐5‐C were characterized by scanning electron microscopy, N₂ adsorption, and powder X‐ray diffraction. The MOF‐5‐C retained the original porous structures of MOF‐5, and showed a high Brunauer–Emmett–Teller surface area (1808 m² g^?1) and large pore volume (3.05 cm³ g^?1). To evaluate its adsorption performance, the MOF‐5‐C was used as an adsorbent for the solid‐phase extraction of four phthalate esters from bottled water, peach juice, and soft drink samples followed by high‐performance liquid chromatographic analysis. Several parameters that could affect the extraction efficiencies were investigated. Under the optimum conditions, a good linearity was achieved in the concentration range of 0.1–50.0 ng mL^?1 for bottled water sample and 0.2–50.0 ng mL^?1 for peach juice and soft drink samples. The limits of detection of the method (S/N = 3) were 0.02 ng mL^?1 for bottled water sample, and 0.04–0.05 ng mL^?1 for peach juice and soft drink samples. The results indicated that the MOF‐5‐C exhibited an excellent adsorption capability for trace levels of phthalate esters, and it could be a promising adsorbent for the preconcentration of other organic compounds.     

MultiSimplex optimisation of the solid-phase microextraction-gas chromatographic-mass spectrometric determination of polycyclic aromatic hydrocarbons,polychlorinated biphenyls and phthalates from water samples

Solid-phase microextraction coupled to GC-MS was optimised for the determination of polycyclic aromatic hydrocarbons (PAHs), phthalate esters and polychlorinated biphenyls (PCBs) in water samples. A 30-microm polydimethylsiloxane fiber was immersed in a 30-ml water sample that contained the analytes of interest (PAHs, PCBs and phthalate esters) and the variables studied were extraction time (15-60 min), extraction temperature (30-90 degrees C), desorption time (1-5 min), desorption temperature (220-270 degrees C) and the addition of sodium chloride (0-9 g). The MultiSimplex programme based on the simplex algorithm was used to establish the optimal conditions. MultiSimplex allowed the simultaneous study of the variables mentioned above and considered the answers of all types of compounds studied in this work. Thus, the optimal conditions obtained allowed the simultaneous determination of PAHs, phthalate esters and PCBs. Furthermore, the accuracy and repeatability of the developed method were calculated from water samples spiked at known concentrations of the analytes. Finally, the optimised method was used to analyse water samples from different sampling points of the Urdaibai and Nerbioi-Ibaizabal estuaries (Biscay, Spain).     

Multivariate optimization of a solid-phase microextraction method for the analysis of phthalate esters in environmental waters

A solid-phase microextraction method (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) has been developed for the determination of the six phthalate esters included in the US Environmental Protection Agency (EPA) Priority Pollutants list in water samples. These compounds are dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP). Detailed discussion of the different parameters, which could affect the extraction process, is presented. Main factors have been studied and optimized by means of a multifactor categorical design. Different commercial fibers, polydimethylsiloxane (PDMS), polydimethylsiloxane-divinylbenzene (PDMS-DVB), polyacrylate (PA), Carboxen-polydimethylsiloxane (CAR-PDMS) and Carbowax-divinylbenzene (CW-DVB), have been investigated, as well as the extraction mode, exposing the fiber directly into the sample (DSPME) or into the headspace over the sample (HS-SPME), and different extraction temperatures. The use of this experimental design allowed for the evaluation of interactions between factors. Extraction kinetics has also been studied. The optimized microextraction method showed linear response and good precision for all target analytes. Detection limits were estimated considering the contamination problems associated to phthalate analysis. They were in the low pg mL(-1), excluding DEHP (100 pg mL(-1)). The applicability of the developed SPME method was demonstrated for several real water samples including mineral, river, industrial port and sewage water samples. All the target analytes were found in real samples. Levels of DEP and DEHP were over 1 ng mL(-1) in some of the samples.     

Mesoporous Silica‐coated Magnetic Nanoparticles for Mixed Hemimicelles Solid‐phase Extraction of Phthalate Esters in Environmental Water Samples with Liquid Chromatographic Analysis

To extract, preconcentrate and determine the trace level of environmental contaminants, a novel mixed hemimicelles solid‐phase extraction (MHSPE) method based on mesoporous silica‐coated magnetic nanoparticles (Fe₃O₄/meso‐SiO₂ NPs) as adsorbent was developed for extraction of phthalate esters from water samples. The Fe₃O₄/meso‐SiO₂ NPs were synthesized by using a combination of hydrothermal method and sol‐gel method. The obtained Fe₃O₄/meso‐SiO₂ NPs possessed a large surface area (570 m²/g), superparamagnetism, and uniform mesopores (2.8 nm). MHSPE parameters, such as the amount of surfactant, pH of sample, shaking and separation time, eluent and breakthrough volume that may influence the extraction of analytes greatly, were further investigated. Under the optimized conditions, the extraction was completed in 20 min and a concentration factor of 500 was achieved by extracting 250 mL water sample. Detection limits obtained of butyl‐benzyl phthalate (BBP), di‐n‐butyl phthalate (DnBP), di‐(2‐ethylhexyl) phthalate (DEHP) and di‐n‐cotyl phthalate (DnOP) were 12, 21, 12, and 32 ng/L, respectively. The proposed method exhibited high extraction efficiency and relatively short time for extracting the target compounds.