Rapid Synergistic Cloud Point Extraction (RS-CPE) with Partial Least Squares (PLS) for the Simultaneous Determination of Chlorophenols (CPs) in Environmental Water Samples Using a Microplate Assay (MPA)

Monolithic fibers were synthesized and applied for the solid-phase microextraction and determination of chlorophenols in environmental water samples by coupling with HPLC. The fibers were prepared by copolymerization of vinylimidazole and ethylene dimethacrylate as functional monomer and cross-linker, respectively. The effect of the preparation conditions of monolithic fibers on the extraction efficiencies was investigated in detail. Several characteristic techniques, such as elemental analysis, infrared spectroscopy, mercury-intrusion porosimetry, and SEM were used to characterize the monolithic material. The effect of the extraction parameters, including desorption solvent, extraction and desorption time, pH values, and ionic strength in sample matrix on the extraction performance was investigated thoroughly. Under the improved extraction conditions, the linear ranges of 2-chlorophenol, 2,4-dichlorophenol and pentachlorophenol were 1.0-200 μg/L and 2.0-200 μg/L for 2,4,6-trichlorophenol. The detection limits (S/N = 3) were in the range of 0.16-0.45 μg/L, the RSDs for intraday and interday precisions were <7.0%. Finally, the proposed method was successfully used to detect different environmental water samples. The recoveries of spiked water samples were ranged from 90.0 to 115%. At the same time, satisfactory repeatability was achieved with RSDs < 9.0%.

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

Solid phase extractive preconcentration coupled to gas chromatography–atomic emission detection for the determination of chlorophenols in water samples

Molecularly imprinted photocatalyst with a structural analogue of template and its application

Preconcentration of chlorophenols in water samples using three-dimensional graphene-based magnetic nanocomposite as absorbent

Dispersive liquid-liquid microextraction (DLLME) coupled with CE was developed for simultaneous determination of five types of chlorophenols (CPs), namely 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,6-dichlorophenol (2,6-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) in water samples. Several parameters affecting DLLME and CE conditions were systematically investigated. Under the optimized DLLME-CE conditions, the five CPs were separated completely within 7.5min and good enrichment factors were obtained of 40, 193, 102, 15, and 107 for 4-CP, 2,4,6-TCP, 2,4-DCP, 2-CP, and 2,6-DCP, respectively. Good linearity was attained in the range of 1-200μg/L for 2,4,6-TCP, 2,4-DCP, 2-300μg/L for 4-CP and 2-CP, and 1-300μg/L for 2,6-DCP, with correlation coefficients (r) over 0.99. The LOD (S/N=3) and the LOQ (S/N=10) were 0.31-0.75μg/L and 1.01-2.43μg/L, respectively. Recoveries ranging from 60.85 to 112.36% were obtained with tap, lake, and river water spiked at three concentration levels and the RSDs (for n=3) were 1.31-11.38%. With the characteristics of simplicity, cost-saving, and environmental friendliness, the developed DLLME-CE method proved to be potentially applicable for the rapid, sensitive, and simultaneous determination of trace CPs in complicated water samples.

The current routes to couple dispersive liquid-liquid microextraction with capillary electrophoresis are the evaporation of water immiscible extractants and the back-extraction of analytes. In this study, a new methodology for this combination using water-in-oil microemulsion electrokinetic chromatography coupled with normal stacking mode on-line sample concentration was developed to analyze chlorophenols in water samples. The analytes were extracted with tributyl phosphate and the extractant dilution (3×) was directly injected into an electrophoresis buffer (7.7cm) containing 5% sodium dodecyl sulfate, 78% 1-butanol, 2% 1-heptane, and 15% sodium acetate solution (pH 8.0). This proposed method is very simple and convenient compared to the conventional procedures. The key parameters affecting separation and concentration were systematically optimized. Under the optimized conditions, dispersive liquid-liquid microextraction contributed an enrichment factor of 45-50, and the overall sensitivity improvement was 312-418-fold. Limits of detection between 1.4 and 3.0ng/mL and limits of quantification between 4.5 and 10.2ng/mL were achieved. Acceptable repeatability lower than 3.0% for migration time and 9.0% for peak areas were obtained. The developed method was successfully applied for analysis of the chlorophenols in real water samples.

Direct determination of chlorophenols in water samples through ultrasound-assisted hollow fiber liquid–liquid–liquid microextraction on-line coupled with high-performance liquid chromatography

Determination of chlorophenols in water samples using simultaneous dispersive liquid–liquid microextraction and derivatization followed by gas chromatography-electron-capture detection

A porous and highly efficient polyaniline-based solid-phase microextraction (SPME) coating was successfully prepared by the electrochemical deposition method. A method based on headspace SPME followed by HPLC was established to rapidly determine trace chlorophenols in water samples. Influential parameters for the SPME, including extraction mode, extraction temperature and time, pH and ionic strength procedures, were investigated intensively. Under the optimized conditions, the proposed method was linear in the range of 0.5-200 μg/L for 4-chlorophenol and 2,4,6-trichlorophenol, 0.2-200 μg/L for 2,4-dichlorophenol and 2-200 μg/L for 2,3,4,6-tetrachlorophenol and pentachlorophenol, with satisfactory correlation coefficients (>0.99). RSDs were <15% (n = 5) and LODs were relatively low (0.10-0.50 μg/L). Compared to commercial 85 μm polyacrylate and 60 μm polydimethylsiloxane/divinylbenzene fibers, the homemade polyaniline fiber showed a higher extraction efficiency. The proposed method has been successfully applied to the determination of chlorophenols in water samples with satisfactory recoveries.

Development of a solid-phase microextraction method with micellar desorption for the determination of chlorophenols in water samples: Comparison with conventional solid-phase microextraction method

Solid-phase extraction (SPE) procedure followed by derivatization and gas chromatography electron capture detection was evaluated for the determination of trace amounts of chlorophenols (CPs) in waters samples. Different parameters affecting extraction efficiency such as, volume of elution solvent, volume and pH of water sample, quantity of sorbent phase were studied and optimized. SPE was carried out on polystyrene-divinylbenzene (Bond Elut ENV) and high recoveries were obtained using 1000 mg of this cartridge for the treatment of 500 mL of acidified water sample. The described method was then tested on spiked tap, mineral, ground and surface water samples. The overall procedure provided limits of detection lower than 20 ng L(-1), recoveries of 70%-106% and an enrichment factor of 500 for the examined CPs in 500 mL water samples. Among the studied compounds, pentachlorophenol was detected in tap water at a concentration level of 0.06 µg L(-1).

In-column micro-high-performance liquid chromatographic concentration-separation prior to ultraviolet detection for the determination of chlorophenols in water samples

Application of surfactant assisted dispersive liquid–liquid microextraction for sample preparation of chlorophenols in water samples

Rapid prediction of multiple wine quality parameters using infrared spectroscopy coupling with chemometric methods