超声辅助分散液液微萃取-高效液相色谱测定水样中的4种邻苯二甲酸酯类增塑剂

建立了采用超声辅助分散液液微萃取技术结合高效液相色谱法(UA-DLLME-HPLC)对4种邻苯二甲酸酯(PAEs)进行富集、检测的方法,并成功应用于实际水样分析。实验中采用富集因子来评价萃取效率,考察并优化了影响萃取效率的主要因素,包括萃取剂类型和用量、分散剂类型和用量、超声时间、离子强度、萃取时间和pH值等。结果表明: 在最佳萃取条件下,该法对4种PAEs（邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯和邻苯二甲酸二正辛酯）具有较高的富集能力,富集因子分别为71、144、169和159;检出限分别为3.78、1.77、3.07和3.30 μg/L。对实验室自来水、某品牌矿泉水以及湖水分别加标50、200及500 μg/L的回收率为82.99%～114.47%,相对标准偏差为1.93%～8.31%。该法简便、快速、环保,可以用于测定实际水样中的PAEs类增塑剂。     

Temperature-assisted ionic liquid dispersive liquid-liquid microextraction combined with high performance liquid chromatography for the determination of PCBs and PBDEs in water and urine samples

We report on silver–gold core-shell nanostructures that contain Methylene Blue (MB) at the gold–silver interface. They can be used as reporter molecules in surface-enhanced Raman scattering (SERS) labels. The labels are stable and have strong SERS activity. TEM imaging revealed that these nanoparticles display bright and dark stripe structures. In addition, these labels can act as probes that can be detected and imaged through the specific Raman signatures of the reporters. We show that such SERS probes can identify cellular structures due to enhanced Raman spectra of intrinsic cellular molecules measured in the local optical fields of the core-shell nanostructures. They also provide structural information on the cellular environment as demonstrated for these nanoparticles as new SERS-active and biocompatible substrates for imaging of live cells.

Carrier-mediated liquid phase microextraction coupled with high performance liquid chromatography for determination of illicit drugs in human urine

A new method was developed for the analysis of illicit drugs in human urine by coupling carrier-mediated liquid phase microextraction (LPME) to high performance liquid chromatography (HPLC). By adding an appropriate carrier in organic phase, simultaneous extraction and enrichment of hydrophilic (morphine and ephedrine) and hydrophobic (pethidine) drugs were achieved. Effects of the types of organic solvents and carriers, the carrier concentration in the organic phase, the HCl concentration in the acceptor solution, the stirring rate, and the extraction time on the enrichment factor of analytes were investigated. Under the optimal experimental conditions, high enrichment factors (202-515) were obtained. The linear detection ranges were 0.1-10 mg L⁻¹ for the studied drugs. The limits of detection (LOD) at signal-to-noise ratio of 3 were 0.05 mg L⁻¹ for both morphine and ephedrine, and 0.02 mg L⁻¹ for pethidine. This method was successfully applied to analysis of ephedrine in real urine specimens, revealing that the determination of illicit drugs in urine was feasible.     

Combination of ionic liquid dispersive liquid-phase microextraction and high performance liquid chromatography for the determination of triazine herbicides in water samples

A temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with high performance liquid chromatography was developed for the enrichment and determination of triazine herbicides such as cyanazine,simazine,and atrazine in water samples.1-Octyl-3-methylimidazolium hexafluorophosphate([C8MIM][PF6]) was selected as the extraction solvent.Several experimental parameters were optimized.Under the optimal conditions,the linear range for cyanazine was in the concentration range of 0.5–80 mg/L and the linear range for simazine and atrazine was in the range of1.0–100 mg/L.The limit of detection(LOD,S/N = 3) was in the ranges of 0.05–0.06 mg/L,and the intra day and inter day precision(RSDs,n = 6) was in the ranges of 3.2%–6.6% and 4.8%–8.9%,respectively.Four real water samples were analyzed with the developed method,and the experimental results showed that the spiked recoveries were satisfactory.All these exhibited that the developed method was a valuable tool for monitoring such pollutants.     

Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

A novel method for the determination of five carbamate pesticides(metolcarb,carbofuran,carbaryl,isoprocard and diethofencard)in water samples was developed by dispersive liquid-liquid microextraction(DLLME)coupled with high performance liquid chromatography-diode array detector(HPLC-DAD).Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results.Under the optimum conditions for the method,the calibration curve was linear in the c...     

Determination of triazine herbicides in environmental samples by dispersive liquid-liquid microextraction coupled with high performance liquid chromatography

A simple, rapid, efficient, and environmentally friendly method for the determination of five triazine herbicides in water and soil samples was developed by using dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). The water samples were directly used for DLLME extraction. For soil samples, the target analytes were first extracted by water-methanol (99:1, v/v). In the DLLME extraction method, chloroform was used as an extraction solvent, and acetonitrile as a dispersive solvent. Under the optimum conditions, the enrichment factors of DLLME were in the range between 183-221. The linearity of the method was obtained in the range of 0.5-200 ng/mL for the water sample analysis, and 1-200 ng/g for the soil samples, respectively. The correlation coefficients ranged from 0.9968 to 0.9999. The limits of detection were 0.05-0.1 ng/mL for the water samples, and 0.1-0.2 ng/g for the soil samples. The proposed method has been successfully applied to the analysis of target triazine herbicides (simazin, atrazine, prometon, ametryn, and prometryn) in water and soil samples with satisfactory results.     

固相微萃取-高效液相色谱联用测定环境水样中双酚A的自由溶解态浓度

应用可忽略耗损固相微萃取与高效液相色谱联用技术测定了环境水样中双酚A的自由溶解态浓度。为了获得高的灵敏度并减小环境因素（如温度和搅拌等）的影响,采用商品化固相微萃取纤维CW／TPR进行平衡采样。在环境水样常见pH（5～8）、缓冲容量（5～200mmol／L）和盐度（0～500mmol／L）条件下,4h可以达到萃取平衡。100mL样品足以避免样品耗损。以配制在250mmol／L NaCl和125mmol／L磷酸盐溶液（pH6．4）中的双酚A标准溶液进行校准,可以将缓冲液（0～200mmol／L）、盐度（0～500mmol／L）和pH（5．7～8．5）的影响控制在15％偏差范围以内。如需更准确的测定,也可以对样品pH值的影响加以校正。pH为6．4时,方法的线性范围为0．1～250μg／L,检出限为0．03μg／L,相对标准偏差（5μg/L,n=3）为1．1％。采用本方法测定了污水处理厂排水口的双酚A的自由溶解态浓度。     

Solid-phase microextraction coupled with high performance liquid chromatography using on-line diode-array and electrochemical detection for the determination of fenitrothion and its main metabolites in environmental water samples

The aim of this study was to develop a methodology for the analysis of the insecticide fenitrothion and its two main environmental metabolites, fenitrooxon and 3-methyl-4-nitrophenol. For this purpose, a solid-phase microextraction (SPME) method coupled to high performance liquid chromatography (LC) was optimized. Two on-line detectors, diode array (DAD) and direct current amperometrical (DCAD) were used in order to determine sensitivity and selectivity. The effects of the extraction parameters, including exposure and desorption time, pH, temperature, salt concentration and desorption mode on the extraction efficiency were studied. A satisfactory reproducibility for extractions from samples at 20 ppb-level with RSD < 12.5% (n = 10) was obtained. The calibration graphs were linear in the range of 10-1000 microg l(-1) and detection limits for the target compounds were between 1.2 and 11.8 microg l(-1) depending on which detector was used. The method was applied for determining fenitrothion and both its metabolites in river waters which run through forest areas near to aerial application of the pesticide.     

On-fibre solid-phase microextraction coupled to conventional liquid chromatography versus in-tube solid-phase microextraction coupled to capillary liquid chromatography for the screening analysis of triazines in water samples

This paper compares the advantages and disadvantages of two different configurations for the extraction of triazines from water samples: (1) on-fibre solid-phase microextraction (SPME) coupled to conventional liquid chromatography (LC); and (2) in-tube SPME coupled to capillary LC. In-tube SPME has been effected either with a packed column or with an open capillary column. A critical evaluation of the main parameters affecting the performance of each method has been carried out in order to select the most suitable approach according to the requirements of the analysis. In the on-fibre SPME configuration the fibre coating was polydimethylsiloxane (PDMS)-divinylbenzene (DVB). The limits of detection (LODs) obtained with this approach under the optimized extraction and desorption conditions were between 25 and 125 microg/L. The in-tube SPME approach with a C18 packed column (35 mm x 0.5 mm I.D., 5 microm particle size) connected to a switching micro-valve provided the best sensitivity; under such configuration the LODs were between 0.025 and 0.5 microg/L. The in-tube SPME approach with an open capillary column coated with PDMS (30 cm x 0.25 mm I.D., 0.25 microm of thickness coating) connected to the injection valve provided LODs between 0.1 and 0.5 microg/L. In all configurations UV detection at 230 nm was used. Atrazine, simazine, propazine, ametryn, prometryn and terbutryn were selected as model compounds.     

A novel molecularly imprinted solid-phase microextraction fiber coupled with high performance liquid chromatography for analysis of trace estrogens in fishery samples

The combination of molecular imprinting and solid-phase microextraction (SPME) technique provides a powerful sample preparation tool in terms of selectivity, simplicity, and flexibility. This paper reports a novel molecularly imprinted polymer (MIP) coated SPME fiber with 17β-estradiol as template by improved multiple co-polymerization method. The obtained fiber exhibits excellent characteristics such as high porosity, good thermal and chemical stability. Extraction performance shows that the MIP-coated fiber has stronger affinity to the template molecule as compared with the commercial SPME fibers and the control polymer-coated fiber without addition of template. Owing to the shape and structural compatibility, the obtained fiber also demonstrated specific selectivity to the structural related compounds of 17β-estradiol, such as estriol, estrone and 17α-ethynylestradiol, and thus can be applied to simultaneous determination of these estrogens from complex samples coupled with high performance liquid chromatography. The variables that influence extraction were investigated. The MIP-coated fiber demonstrated its efficiency for extraction of estrogens in fishery samples. The detection limits were in the range of 0.98-2.39 μg L⁻¹, and the recoveries were 80.0-83.6% and 85.0-94.1% for fish and shrimp tissue samples, respectively.     

Determination of diphenylether herbicides in water samples by solid-phase microextraction coupled to liquid chromatography

Solid-phase microextraction (SPME) coupled to LC for the analysis of five diphenylether herbicides (aclonifen, bifenox, fluoroglycofen-ethyl, oxyfluorfen, and lactofen) is described. Various parameters of extraction of analytes onto the fiber (such as type of fiber, extraction time and temperature, pH, impact of salt and organic solute) and desorption from the fiber in the desorption chamber prior to separation (such as type and composition of desorption solvent, desorption mode, soaking time, and flush-out time) were studied and optimized. Four commercially available SPME fibers were studied. PDMS/divinylbenzene (PDMS/DVB, 60 microm) and carbowax/ templated resin (CW/TPR, 50 microm) fibers were selected due to better extraction efficiencies. Repeatability (RSD, < 7%), correlation coefficient (> 0.994), and detection limit (0.33-1.74 and 0.22-1.94 ng/mL, respectively, for PDMS/DVB and CW/TPR) were investigated. Relative recovery (81-104% for PDMS/DVB and 83-100% for CW/TPR fiber) values have also been calculated. The developed method was successfully applied to the analysis of river water and water collected from a vegetable garden.     

Analysis of triazine in water samples by solid-phase microextraction coupled with high-performance liquid chromatography

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) for the determination of triazine is described. Carbowax/templated resin (CW/TPR, 50 μm), polydimethylsiloxane/divinylbenzene (PDMS/DVB, 60 μm), polydimethylsiloxane (PDMS, 100 μm), and polyacrylate (PA, 85 μm) fibers were evaluated for extraction of the triazines. CW/TPR and PDMS/DVB fibers were selected for further study. Several parameters of the extraction and desorption procedure were studied and optimized (such as types of fibers, desorption mode, desorption time, compositions of solvent for desorption, soaking periods and the flow rate during desorption period, extraction time, temperature, pH, and ionic strength of samples). Both CW/TPR and PDMS/DVB fibers are acceptable; a simple calibration-curve method based on simple aqueous standards can be used. The linearity of this method for analyzing standard solution has been investigated over the range 5-1000 ng mL⁻¹ for both PDMS/DVB and CW/TPR fibers. All the correlation coefficients in the range 5-1000 ng mL⁻¹ were better than 0.995 except Simazine and Atratone by CW/TPR fiber. The R.S.D.s range from 4.4% to 8.8 % (PDMS/DVB fiber) and from 2.4% to 7.2% (CW/TPR fiber). Method-detection limits (MDL) are in the range 1.2-2.6 and 2.8-3.4 ng mL⁻¹ for the two fibers. These methods were applied to the determination of trazines in environmental water samples (lake water).     

Fluorometric determination of isoniazid and its metabolites in urine by high performance liquid chromatography

Summary A rapid, simple, and accurate method was developed for the determination of isoniazid and its metabolites (isonicotinic acid, acetylisoniazid and isonicotinylglycine) in urine by high-performance liquid chromatography. Urine is diluted with the mobile phase. After centrifugation, an aliquot of the supernatant is injected into the chromatograph. Isoniazid and its metabolites are separated by reversed-phase ionpairing chromatography with a mobile phase containing propanesulfonate and detected by fluorometry using postcolumn derivatization at high temperature (150°C) with hydrogen peroxide. The method was applied to the analysis of urine from patients receiving isoniazid therapy.     

Ultratrace determination of carbamate pesticides in water samples by temperature controlled ionic liquid dispersive liquid phase microextraction combined with high performance liquid phase chromatography

A simple and sensitive method was developed for the determination of three carbamate pesticides in water samples. It is based on temperature controlled ionic liquid dispersive liquid phase microextraction combined with high-performance liquid chromatography. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extractant, and the factors affecting the extraction were investigated in detail. The detection limits obtained for isoprocarb, diethofencarb and fenothiocarb are 0.91, 0.45, and 1.40 μgL^-1, respectively, and the precisions are in the range between 1.0 and 1.8% (n?=?6). The method was validated with environmental water samples and the results indicate that it represents a viable alternative to existing methods.

Enrichment and sensitive determination of dichlorodiphenyltrichloroethane and its metabolites with temperature controlled ionic liquid dispersive liquid phase microextraction prior to high performance liquid phase chromatography

Dichlorodiphenyltrichloroethane (DDT) and its main metabolites are important environmental pollutants and have been in the focusing center. It is of great value to develop simple, rapid, sensitive and easy to operate method for monitoring them. Present work established a novel temperature controlled ionic liquid dispersive liquid phase microextraction method in combination with high performance liquid chromatography for the enrichment and determination of DDT and its metabolites. Proposed method used only ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]) for the enrichment and overcame the demerits of conventional single drop liquid phase microextraction and dispersive liquid-liquid microextraction. Temperature has two functions here, one is to promote the dispersing of ionic liquid into the solution and forming infinitesimal micro-drop and increasing the chance of the analytes extracted into ionic liquid phase, and the other one is to perform phase-separation. A series of factors that would affect the extraction performance was systematically investigated and optimized. The experimental results indicated that the detection limits obtained for p,p′-DDD, p,p′-DDT, o,p′-DDT and p,p′-DDE were 0.24, 0.24, 0.45, 0.24 ng mL⁻¹, respectively. The linear ranges for them were from 1.0 to 100 ng mL⁻¹, and the precisions were between 3.8% and 6.7% (n = 6). The proposed method was validated with four real-world samples and excellent results were achieved.     

Supramolecular-based solvent microextraction of carbaryl in water samples followed by high performance liquid chromatography determination

In this study, a simple, rapid, low cost, sensitive and environmentally friendly technique, supramolecular solvent microextraction (SM-SME) followed by high performance liquid chromatography-ultraviolet has been proposed to extract carbaryl from water samples. Parameters, affecting the SM-SME performance such as the weight of decanoic acid (DeA), volume of tetrahydrofuran (THF), pH and salt concentration, were studied and optimised. The effect of the pH on the extraction efficiency was evaluated by one–factor-at-a-time methodology, but the other variables were optimised by a face-centred cube central composite design methodology. Optimum extraction conditions were obtained: DeA: 70 mg; THF: 650 µL; salt concentration: 10% (w/v) NaCl and pH = 2–4), and the performance of the proposed method was evaluated. Under the optimum conditions, good linearity (1.0–500 µg L^?1, r² = 0.9994) was obtained. Limit of detection and limit of quantification were 0.3–1.0 µg L^?1, respectively. Also, the recoveries of the carbaryl were obtained in the ranged from 96% to 105%. Finally, proposed method was successfully applied for the determination of the carbaryl in the water samples of farms run-off and rivers and satisfactory results were obtained.     

Combination of ultrasound-assisted ionic liquid dispersive liquid-phase microextraction and high performance liquid chromatography for the sensitive determination of benzoylureas pesticides in environmental water samples

This paper describes a new method for rapid and sensitive determination of diflubenzuron, flufenoxuron, triflumuron and chlorfluazuron in water samples by ultrasound-assisted ionic liquid dispersive liquid-phase microextraction in combination with HPLC. Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) was used as the extraction solvent for the enrichment of four benzoylurea (BU) pesticides. Factors such as volume of [C(6)MIM][PF(6)], sonication time, sample pH, extraction time, centrifuging time and salting-out effect were systematically investigated. Under the optimum conditions, an excellent linear relationship was achieved in the range of 1.0-100?μg/L. The detection limits varied from 0.21 to 0.45?μg/L and the precision of the method was below 6.9% (RSD, n=6). The proposed method was successfully applied for the determination of these BU pesticides in water samples and excellent spiked recoveries were achieved. All these results demonstrated that this procedure provided a new simple, rapid, easy to operate, efficient and sensitive method for the analysis of BU pesticides in aqueous samples.     

分散液-液微萃取-高效液相色谱法测定环境水样中的多环芳烃

建立了简便、快速、有效的分散液-液微萃取-高效液相色谱-荧光检测(DLLME-HPLC-FLD)测定环境水样中15种多环芳烃(PAHs)的方法。重点探讨了萃取剂的种类和用量、分散剂的种类和用量以及萃取时间等对PAHs萃取效率的影响。在优化的条件下,评价了方法的可靠性。15种PAHs在0.01～10 μg/L范围内呈良好的线性关系,相关系数r均不小于0.9913,峰面积的相对标准偏差(RSD)在2.3%～4.7%之间(n=6)。在优化条件下,富集因子和萃取回收率良好,分别为674～1032和67.4%～103.2%,15种PAHs的检出限(S/N=3)在0.0003～0.002 μg/L之间。建立的方法应用于敖江水样中PAHs的检测,平均加标回收率在79.5%～92.3%之间,RSD在4.3%～6.7%范围内(n=5)。该方法适用于环境水样中痕量PAHs的分析。