Ionic liquid sensitized fluorescence determination of four isoquinoline alkaloids

The fluorescence spectra of berberine, palmatine, jatrorrhizine, and coptisine in ionic liquids were studied and found to increase significantly in ionic liquids, with [C(8)MIM][PF(6)] having the greatest increase. Further studies showed that these drugs could be extracted from an aqueous solution by [C(8)MIM][PF(6)] using the temperature-assisted ionic liquid dispersive liquid phase microextraction method. The enrichment factors were 81.8-82.3, and the extraction recovery was 98.5%, 98.1%, 98.3%, and 98.8% for berberine, palmatine, jatrorrhizine, and coptisine, respectively. Based on the [C(8)MIM][PF(6)] preconcentration, separation, and sensitized fluorescence for these drugs, a new selective and sensitive method for the determination of concentration of these four drugs in aqueous samples was presented. At optimum conditions, the linear relationship was obtained in the ranges of 0.8-130 ng mL(-1), 0.9-160 ng mL(-1), 0.7-140 ng mL(-1), and 0.6-110 ng mL(-1), respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine, and plasma samples.     

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.     

Ionic liquid-based liquid-phase microextraction, a new sample enrichment procedure for liquid chromatography

Room temperature ionic liquids (RTILs) were used as extraction solvent in liquid-phase microextraction (LPME) coupled with liquid chromatography. Using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) as extraction solvent, some parameters related to LPME of 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP) were optimized. Although [C6MIM][PF6] can suspend a much larger volume of drop on the needle of the microsyringe than the conventional solvents such as 1-octanol and carbon tetrachloride, the method sensitivity was analyte dependent because of the different partition coefficients and the relatively large viscosity of [C6MIM][PF6]. The proposed procedure has a detection limit and enrichment factor of 0.3 microg l(-1) and 163 for 4-NP, and 0.7 microg l(-1) and 130 for 4-t-OP, respectively. Aqueous samples including tap water, river water, and effluent from sewage treatment plant were analyzed by the proposed method and the recoveries at 10 microg l(-1) spiked level were in the range of 90-113%.     

Quantitation of antioxidants in water samples using ionic liquid dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection

A simple and efficient method, ionic liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), has been applied for the extraction and determination of some antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) in water samples. The microextraction efficiency factors were investigated and optimized: 1-hexyl-3-methylimidazolium hexafluorophosphate [C(6)MIM][PF(6)] (0.06 g) as extracting solvent, methanol (0.5 mL) as disperser solvent without salt addition. Under the selected conditions, enrichment factors up to 48-fold, limits of detection (LODs) of 5.0-10.0 ng/mL and dynamic linear ranges of 25-1500 ng/mL were obtained. A reasonable repeatability (RSD≤11.8%, n=5) with satisfactory linearity (r(2)≥0.9954) of the results illustrated a good performance of the presented method. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 85 to 118%. Finally, the method was successfully applied for determination of the analytes in several real water samples.     

Screening the extractability of some typical environmental pollutants by ionic liquids in liquid-phase microextraction

The extractability of some typical environmental pollutants in ionic liquids (ILs) was screened by using a simple one-step liquid phase microextraction procedure. It was demonstrated that 1-alkyl-3-methylimidazolium hexafluorophosphate ([CnMIM][PF6], n = 4, 8), two typical ILs, could effectively extract a set of 45 typical environmental pollutants including BTEX (benzene, toluene, ethylbenzene, and xylene), polycyclic aromatic hydrocarbons, phthalates, phenols, aromatic amines, herbicides, organotin, and organomecury. Analytes in 10 mL sample solution held in a 15 mL vial were extracted by a 5 microL drop of ILs suspended on the needle of a high-performance liquid chromatography (HPLC) microsyringe; this was followed by HPLC, atomic absorption spectrometry, or cold-vapor atomic fluorescence spectrometry determination. The enrichment factors determined were in the range of 5-168 for 15 min extraction by [C4MIM][PF6] and 4-178 for 30 min extraction by [C8MIM][PF6], respectively, which indicates that ILs might be considered as potential environmentally benign alternative recyclable solvents for the enrichment of environmental pollutants.     

Dispersive liquid-liquid microextraction of pesticides and metabolites from soils using 1,3-dipentylimidazolium hexafluorophosphate ionic liquid as an alternative extraction solvent

In this work, the use of the ionic liquid (IL) 1,3-dipentylimidazolium hexafluorophosphate ([PPIm][PF?]) as an alternative extractant for IL dispersive liquid-liquid microextraction (IL-DLLME) of a group of pesticides and metabolites (2-aminobenzimidazole, carbendazim/benomyl, thiabendazole, fuberidazole, carbaryl, 1-naphthol, and triazophos) from soils is described. After performing an initial ultrasound-assisted extraction (USE), the IL-DLLME procedure was applied for the extraction of these organic analytes from soil extracts. Separation and quantification was achieved by high-performance liquid chromatography (HPLC) with fluorescence detection (FD). Calibration, precision, and accuracy of the described USE-IL-DLLME-HPLC-FD method using [PPIm][PF?] as an alternative extractant was evaluated with two soils of different physicochemical properties. Accuracy percentages were in the range 93-118% with RSD values below 20%. A comparison of the performance of [PPIm][PF?] versus that of the so-common 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF?]) was accomplished. Results indicate a comparable extraction efficiency with both ILs, being slightly higher with [HMIm][PF?] for the metabolite 2-aminobenzimidazole, and slightly higher with [PPIm][PF?] for triazophos. In all cases, LODs were in the low ng/g range (0.02-14.2 ng/g for [HMIm][PF?] and 0.02-60.5 ng/g for [PPIm][PF?]). As a result, the current work constitutes a starting point for the use of the IL [PPIm][PF?] for further analytical approaches.     

Application of ionic‐liquid‐supported magnetic dispersive solid‐phase microextraction for the determination of acaricides in fruit juice samples

In this study, ionic liquid (IL) supported magnetic dispersive solid‐phase microextraction was developed and a systematic investigation was conducted on imidazolium ILs for their extraction performance. This nano‐based pretreatment procedure was then applied for the determination of acaricides in fruit juice samples for the first time. A feature of this technique is that the commonly laborious chemical modification of magnetic nanoparticles (MNPs) was skillfully circumvented. Because of the combination of ILs, dispersive liquid–liquid microextraction, and dispersive MNP solid‐phase microextraction, the extraction efficiency can be significantly improved using commercial MNPs. Parameters of the extraction method were investigated by one‐factor‐at‐a‐time approach. The optimal experimental conditions were as follows: emulsification for 2 min by sonication with the addition of 50 μL [C₆MIM][NTf₂] in the dispersive liquid–liquid microextraction step and vortexing for 90 s after adding 40 mg spherical barium ferrite nanoparticles (20 nm). The desorption time was 2 min. Good linearity (0.5–500 ng/mL) and detection limits within the range of 0.05–0.53 ng/mL were achieved. The application of the proposed method was demonstrated by the analysis of real fruit juice samples, in which recoveries between 85.1 and 99.6% were obtained.     

Extraction and Determination of Two Antidepressant Drugs in Human Plasma by Dispersive Liquid–Liquid Microextraction‒HPLC

In this study, an effective method of ultrasound-assisted ionic liquid based dispersive liquid–liquid microextraction (UA?IL?DLLME) coupled with HPLC was applied for extraction and determination of two antidepressant drugs: venlafaxine hydrochloride and amitriptyline hydrochloride from human plasma samples. Three ionic liquids were studied: 1-butyl-3-methyl imidazolium hexafluorophosphate, 1-hexyl-3- methyl imidazolium hexa-fluoro-phosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate [C8MIM][PF6]. Various factors affect the stages and efficiency of extraction, some of which are pH of sample solution, type and volume of ionic liquid, the time of ultrasonication, centrifuging time and rate, and the ionic strength of solution. In this research, optimum conditions were obtained as 55 μL of [C8MIM][PF6] selected as ionic liquid, pH 11, 2% NaCl, 4 min ultrasonication and 5 min centrifuging at 3500 rpm. Under the optimized conditions, the linearity was obtained in the range of 0.2 to 250 μg/L. The limits of detection were 0.5 μg/L for venlafaxine and 0.8 μg/L for amitriptyline. Pre-concentration factors were 1.3 × 10³ for venlafaxine and 1.2 × 10³ for amitriptyline. The UA?IL?DLLME method coupled with HPLC was successfully used for the determination of venlafaxine and amitriptyline spiked into the real samples of human plasma.     

Ionic liquid for high temperature headspace liquid-phase microextraction of chlorinated anilines in environmental water samples

Based on the non-volatility of room temperature ionic liquids (IL), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) IL was employed as an advantageous extraction solvent for high temperature headspace liquid-phase microextraction (LPME) of chloroanilines in environmental water samples. At high temperature of 90 degrees C, 4-chloroaniline, 2-chloroaniline, 3,4-dichloroaniline, and 2,4-dichloroaniline were extracted into a 10 microl drop of [C4MIM][PF6] suspended on the needle of a high-performance liquid chromatography (HPLC) microsyringe held at the headspace of the samples. Then, the IL was injected directly into the HPLC system for determination. Parameters related to LPME were optimized, and high selectivity and low detection limits of the four chlorinated anilines were obtained because the extraction was performed at high temperature in headspace mode and the very high affinity between IL and chlorinated anilines. The proposed procedure was applied for the analysis of the real samples including tap water, river water and wastewater samples from a petrochemical plant and a printworks, and only 3,4-dichloroaniline was detected in the printworks wastewater at 88.2 microg l(-1) level. The recoveries for the four chlorinated anilines in the four samples were all in the range of 81.9-99.6% at 25 microg l(-1) spiked level.     

超声辅助离子液体分散液相微萃取-高效液相色谱法测定废水中雌激素的研究

将离子液体、分散液相微萃取与超声萃取技术结合,采用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C4 MIM][PF6])为萃取剂,建立了超声辅助离子液体分散液相微萃取-高效液相色谱法分析废水中3种雌激素物质(己烯雌酚、双烯雌酚、己烷雌酚)方法.试验采用50μL的离子液体,考察了溶液体积、溶液pH值、超声时间、静置时间、离心时间等因素对富集效果的影响.最佳的萃取条件为:溶液体积为6 mL,甲醇体积0.3 mL,溶液pH值为2.0,超声时间6min,静置时间30min,离心时间10 min.在优化的萃取条件下,3种雌激素的富集倍数可达到96.8～112.4倍;方法的线性范围为0.5-100.0μg/L;检出限为0.25～0.50μ/L.对浓度为5.0μg/L的3种物质测定6次的相对标准偏差为9.2%～10.8%.     

超声辅助离子液体液相微萃取-高效液相色谱法分析水样中加替沙星或氟罗沙星

建立了一种采用离子液体1-己基-3-甲基咪唑六氟磷酸([C6mim][PF6])为萃取剂,超声辅助离子液体液相微萃取-高效液相色谱法分析水样中加替沙星和氟罗沙星的方法。 实验考察了溶液酸度、离子液体用量等因素对萃取的影响。在pH值分别为3.3、2.1的加替沙星和氟罗沙星水样中,加入0.4 mL [C6mim][PF6],超声,离心,离子液体相直接用于HPLC进行分析。 该方法的线性范围为0.5~50 mg/L,测定加替沙星和氟罗沙星的相对标准偏差(n=5)为2.80%和5.93%,二者的检出限分别为0.46、0.97 μg/L,该方法萃取水样中加替沙星的加标回收率为80.5%~89.5%,氟罗沙星的加标回收率可达93.3%~99.0%。     

Determination of sudan dyes in red wine and fruit juice using ionic liquid-based liquid-liquid microextraction and high-performance liquid chromatography

The liquid-liquid microextraction (LLME) was developed for extracting sudan dyes from red wine and fruit juice. Room temperature ionic liquid was used as the extraction solvent. The target analytes were determined by high-performance liquid chromatography. The extraction parameters were optimized. The optimal conditions are as follows: volume of [C(6)MIM][PF(6)] 50 μL; the extraction time 10 min; pH value of the sample solution 7.0; NaCl concentration in sample solution 5%. The extraction recoveries for the analytes in red wine and fruit samples are 86.79-108.28 and 68.54-85.66%, whereas RSDs are 1.42-5.12 and 1.43-6.19%, respectively. The limits of detection and quantification were 0.428 and 1.426 ng/mL for sudan I, 0.938 and 3.127 ng/mL for sudan II, 1.334 and 4.445 ng/mL for sudan III, 1.454 and 4.846 ng/mL for sudan IV, respectively. Compared with conventional liquid-liquid extraction (CLLE) and ultrasonic extraction (UE), when LLME was applied, the sample amount was less (LLME: 4 mL; CLLE: 10 mL; UE: 10 mL), the extraction time was shorter (LLME: 15 min; CLLE: 110 min; UE: 50 min) and the extraction solvent amount was less (LLME: 0.05 mL IL; CLLE: 15 mL hexane; UE: 20 mL hexane). The proposed method offers a simple, rapid and efficient sample preparation for determining sudan dyes in red wine and fruit juice samples.     

Determination of triclosan and triclocarban in environmental water samples with ionic liquid/ionic liquid dispersive liquid-liquid microextraction prior to HPLC-ESI-MS/MS

A hydrophobic ionic liquid was finely dispersed in aqueous solution along with a hydrophilic ionic liquid. Following centrifugation, the two phases aggregate to form relatively large droplets. Based on this phenomenon, a method termed ionic liquid/ionic liquid dispersive liquid-liquid microextraction was developed. It was applied to the enrichment of triclosan (TCS) and triclocarban (TCC) from water samples prior to HPLC with electrospray tandem MS detection. The type and volume of the hydrophobic ionic liquid (the extraction solvent) and the hydrophilic ionic liquid (the disperser solvent), salt content, and extraction time were optimized. Under optimum conditions, the method gives a linear response in the concentration ranges from 0.5 to 100???g L^?1 for TCC and from 2.5 to 500???g L^?1 for TCS, respectively. The limits of detection are 0.23 and 0.35???g L^?1, and the repeatability is 5.4 and 6.4% for TCC and TCS, respectively. The method was validated with four environmental water samples, and average recoveries of spiked samples were in the range from 88% to 111%. The results indicate that the method is a promising new approach for the rapid enrichment and determination of organic pollutants.

苄基功能化离子液体对有机磷和苯环化合物的分散液-液微萃取性能研究

以苄基功能化的离子液体1-苄基-3-甲基咪唑双三氟甲烷磺酰亚胺(1-Benzyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide,[BeMIM][Tf2 N])作为分散液-液微萃取的萃取剂,与高效液相色谱联用,用于环境水样中5种有机磷农药(辛硫磷、杀螟松、毒死蜱、甲拌磷和对硫磷)以及2种苯环化合物(氯化萘和蒽)的萃取与富集。并与其它离子液体([OMIM][Tf2 N])以及普通有机溶剂(CCl4和 C2 Cl4)的萃取效能进行了对比。萃取优化条件为：40μL [BeMIM][Tf2 N]作为萃取剂,1 mL 甲醇作为分散剂,离心时间5 min,样品溶液中不添加盐。在优化的条件下,本方法的线性关系良好(R2=0.9994~0.9998);对10,40和100μg/ L 不同添加浓度重复测定5次的日内和日间 RSD 分别为1.1%~4.3%和0.8%~4.8%,LOD 为0.01~1.0μg/ L (S/ N=3)。将本方法用于3种实际水样中目标分析物的测定,加标回收率和 RSD 分别为82.7%~118.3%和0.7%~5.6%。由于在咪唑环上引入了苄基基团,[BeMIM][Tf2 N]与目标分析物之间除存在疏水作用外,还存在π-π作用,故对目标物的萃取效率明显提高,富集倍数和回收率分别高达339和81.4%。测定了分析物在[BeMIM][Tf2 N]-DLLME 体系中的分配系数,对萃取机制进行初步探讨。     

Ionic liquid-based dispersive liquid-liquid microextraction with back-extraction coupled with capillary electrophoresis to determine phenolic compounds

Ionic liquid (IL) based dispersive liquid-liquid microextraction (DLLME) with back-extraction coupled with capillary electrophoresis ultraviolet detection was developed to determine four phenolic compounds (bisphenol-A, β-naphthol, α-naphthol, 2, 4-dichlorophenol) in aqueous cosmetics. The developed method was used to preconcentrate and clean up the four phenolic compounds including two steps. The analytes were transferred into room temperature ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate, [C(8) MIM][PF(6) ]) rich-phase in the first step. In the second step, the analytes were back-extracted into the alkaline aqueous phase. The effects of extraction parameters, such as type and volume of extraction solvent, type and volume of disperser, extraction and centrifugal time, sample pH, salt addition, and concentration and volume of NaOH in back-extraction were investigated. Under the optimal experimental conditions, the preconcentration factors were 60.1 for bisphenol-A, 52.7 for β-naphthol, 49.2 for α-naphthol, and 18.0 for 2, 4-dichlorophenol. The limits of detection for bisphenol-A, β-naphthol, α-naphthol and 2, 4-dichlorophenol were 5, 5, 8, and 100 ng mL(-1), respectively. Four kinds of aqueous cosmetics including toner, soften lotion, make-up remover, and perfume were analyzed and yielded recoveries ranging from 81.6% to 119.4%. The main advantages of the proposed method are quick, easy, cheap, and effective.     

Comparison of two ultrasound‐enhanced microextractions combined with HPLC for determining acaricides in water

An ultrasound‐enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound‐enhanced ionic‐liquid‐assisted dispersive liquid–liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C₈MIM][PF₆]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic‐liquid‐assisted dispersive liquid–liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.     

Ionic liquid-based single-drop liquid-phase microextraction combined with high-performance liquid chromatography for the determination of sulfonamides in environmental water

A simple, rapid and environment‐friendly technique of single‐drop liquid‐phase microextraction has been developed for the determination of sulfonamides in environmental water. Several important parameters including stirring rate, extraction solvent, extraction pH, salinity and extraction time were optimized to maximize the extract efficiency. Extraction solvent 1‐octyl‐3‐methylimidazolium hexafluorophosphate [C₈MIM][PF₆] ionic liquid showed better extraction efficiency than 1‐butyl‐3‐methylimidazolium hexafluorophosphate [C₄MIM][PF₆] and 1‐octanol. The optimum experimental conditions were: pH, 4.5; sodium chloride content, 36% w/v; extraction time, 20 min. This method provided low detection limits (0.5–1 ng/mL), good repeatability (the RSD ranging from 4.2 to 9.9%, n=5) and wide linear range (1–1500 ng/mL), with determination coefficients (r²) higher than 0.9989 for all the target compounds. Real sample analysis showed relative recoveries between 63.5 and 115.8% for all the target compounds.     

Sensitive determination of free benzophenone-3 in human urine samples based on an ionic liquid as extractant phase in single-drop microextraction prior to liquid chromatography analysis

Benzophenone-3 (BZ3), one of the compounds most commonly used as UV filter in cosmetic products, can be absorbed through the skin into the human body, since it can be found at trace levels in urine from users of cosmetic products that contain BZ3. Moreover, different undesirable effects have been attributed to this compound. Thus, sensitive analytical methods to monitor urinary excretion of this compound should be developed. This paper presents a selective and sensitive methodology for BZ3 determination at ultratrace levels in human urine samples. The methodology is based on a novel microextraction technique, known as single-drop microextraction (SDME). An ionic liquid (IL) has been used as extractant phase instead of an organic solvent. After the microextraction process, the extractant phase was injected into a liquid chromatography system. The variables of interest in the SDME process were optimized using a multivariate optimization approach. A Plackett-Burman design for screening and a circumscribed central composite design for optimizing the significant variables were applied. Ionic strength, extraction time, stirring speed, pH, ionic liquid type, drop volume and sample volume were the variables studied. The optimum experimental conditions found were: sodium chloride concentration, 13% (w/v); extraction time, 25 min; stirring speed, 900 rpm; pH, 2; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]); drop volume, 5 microL; and sample volume, 10 mL. The proposed method requires a standard addition calibration approach, and it has been successfully employed to determine free BZ3 in urine samples coming from human volunteers who applied a sunscreen cosmetic containing this UV filter. The limit of detection was in the order of 1.3 ng mL(-1) and repeatability of the method, expressed as relative standard deviation, was 6% (n=8).     

Determination of some organophosphorus pesticides in water and watermelon samples by microextraction prior to high-performance liquid chromatography

A novel method based on simultaneous liquid-liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-liquid phase microextraction has been developed for the determination of six organophosphorus pesticides, i.e. isocarbophos, phosmet, parathion-methyl, triazophos, fonofos and phoxim, in water and watermelon samples prior to high-performance liquid chromatography (HPLC). Under the optimum conditions, the method shows a good linearity within a range of 1-200 ng/mL for water samples and 5-200 ng/g for watermelon samples, with the correlation coefficients (r) varying from 0.9990 to 0.9997 and 0.9986 to 0.9995, respectively. The limits of detection (LODs) were in the range between 0.1 and 0.3 ng/mL for water samples and between 1.0 and 1.5 ng/g for watermelon samples. The recoveries of the method at spiking levels of 5.0 and 50.0 ng/mL for water samples were between 85.4 and 100.8%, and at spiking levels of 5.0 and 50.0 ng/g for watermelon samples, they were between 82.6 and 92.4%, with the relative standard deviations (RSDs) varying from 4.5-6.9% and 5.2-7.4%, respectively. The results suggested that the developed method represents a simple, low-cost, high analytes preconcentration and excellent sample cleanup procedure for the determination of organophosphorus pesticides in water and watermelon samples.     

Direct determination of chlorophenols in environmental water samples by hollow fiber supported ionic liquid membrane extraction coupled with high-performance liquid chromatography

The 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) ionic liquid was immobilized in the pores of a polypropylene hollow fiber for hollow fiber-protected liquid-phase microextraction. Analytes including 4-chlorophenol (4-CP), 3-chorophenol (3-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) were extracted into this ionic liquid membrane, and back extracted into 10microL sodium hydroxide acceptor solution in the lumen of the hollow fiber. Then, the acceptor solution was withdrawn into the high-performance liquid chromatography (HPLC) microsyringe connected to the hollow fiber, and directly injected into the HPLC system for analysis. Some parameters that might affect the extraction efficiency were optimized, and low detection limits (0.5microgL(-1) for 4-CP, 3-CP, DCP and 1.0microgL(-1) for TCP) were obtained. Good repeatability was achieved because of the stability of the hollow fiber-supported ionic liquid membrane. The proposed procedure was applied for direct determination of the four chlorophenols in some real water samples including groundwater, river water, wastewater and tap water. All of the four chlorophenols in these water samples were under the limits of determination, and the recoveries were in the range of 70.0-95.7% at 5microgL(-1) spiked level.