Solid-phase Extraction Of Phenolic Compounds Research Articles

A poly(glycidyl-co-ethylene dimethacrylate) nanohybrid modified with β-cyclodextrin as a sorbent for solid-phase extraction of phenolic compounds.

A hybrid material made of β-cyclodextrin anchored to a polymeric network is described and evaluated as a sorbent for solid-phase extraction of phenolic compounds (phenol, cresol isomers, 2-methoxy-4-vinylphenol, 4-ethylphenol, 4-vinylphenol, 4-ethylguaiacol, guaiacol, and eugenol). The polymeric backbone of the sorbent consists of a poly(glycidyl-co-ethylene dimethacrylate) network, whose surface has been modified with β-cyclodextrin by a click-chemistry based procedure. The resulting material has been characterized by different techniques, and it has shown to be viable as a sorbent for its use in extraction cartridges. In this way, a method for the determination of the above analytes in tea has been validated. Under optimum conditions, the method has good repeatability, with coefficients of variation between 0.6 and 7.2%. In addition, recoveries from spiked samples at the level of 50μgL-1 are between 57 and 101%. The method has been then applied to the determination of phenolic compounds in the drinkable portion of infusions made from tea bags. The quantification has been carried out by using gas chromatography coupled to a mass spectrometry detector. Following their elution from the sorbent with a mixture of acetonitrile and methanol, the limits of quantification reached are between 4.6 and 400μgL-1. Results have been compared with those obtained with a reference method by using the paired t-test for comparing individual differences. The solid phase is reusable, and no cyclodextrin is lost during extraction due to its covalent anchoring to the polymeric support. Graphical abstract Schematic representation of the structure and characterization of the hybrid material made of β-cyclodextrin anchored to a polymeric network. The material is described and evaluated as a sorbent for the solid-phase extraction of phenolic compounds.

Carbon quantum dots-modified ferrofluid for dispersive solid-phase extraction of phenolic compounds in water and milk samples

In this study, novel carbon quantum dots/oleic acid-coated Fe3O4 composites (Fe3O4-OA/CQDs) were successfully synthesized via a simple synthesis strategy and used to prepare the ferrofluid for the extraction and determination of phenolic compounds from water and pretreated milk samples followed by HPLC. The ferrofluid was composed of ionic liquids (ILs) and Fe3O4-OA/CQDs. With the introduction of CQDs, the ferrofluid showed good dispersing capability in aqueous samples, and the method exhibited lower relative standard deviations (RSDs) (1.1–2.1%), which indicated its good reproducibility. In addition, a proper carbon chain length for ILs might maintain the integrity of the ferrofluid during the extraction process and increase the extraction efficiency of the method. Under the optimum conditions, the limits of detection were in the range of 0.09–0.17μgL−1. And the intra-day and inter-day precision (RSD%) for the analytes at 20 and 100μgL−1 were in the range of 1.5–2.6% and 1.6–2.8%, respectively. The recoveries of bisphenols and 4-tert-octylphenol in water and milk samples were between 94.5 and 102.1%, and the RSDs were all in range of 1.7 to 4.1%.

Enrichment of phenolic compounds from water samples by using magnetic Fe3O4 nanoparticles coated with a Keggin type heteropoly acid of type H6[BFe(OH2)W11O39] as a sorbent

The paper describes a new sorbent referred to as BW11Fe which is a Keggin-type heteropolyacid of type H6[BFe(OH2)W11O39] supported on aminopropyl modified silica-coated magnetite nanoparticles (BW11Fe@APSCM-NPs). The sorbent combines the advantages of heteropoly acid and magnetic nanoparticles and possesses large capacity, good interactions with analytes, tunability of the active sites, rapid removal and easy separation of the solid phase. This makes it an excellent sorbent for extracting the phenolic compounds from water samples. Materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and FT-IR. The BW11Fe@APSCM-NPs were applied to the magnetic solid-phase extraction of phenolic compounds from water samples prior to their determination by gas chromatography with flame ionization detection. Under optimal conditions, the calibration plots for the phenols studied (phenol, 4-chlorophenol, o-cresol, m-cresol and 4-aminophenol) are linear in the range from 0.04 to 200 ng⋅mL−1. The method displays detection limits (at an S/N ratio of 3) that range between 0.01 and 0.2 ng⋅mL−1. The repeatability was investigated and gave relative standard deviations of <7.5% (for n = 5). The method was successfully employed to the extraction of the phenolic compounds from water samples and recoveries are in the order of 90.1 to 99.4%.

Facile synthesis of poly(ionic liquid)‐bonded magnetic nanospheres as a high‐performance sorbent for the pretreatment and determination of phenolic compounds in water samples

Poly(ionic liquid)-bonded magnetic nanospheres were easily synthesized and applied to the pretreatment and determination of phenolic compounds in water samples, which have detrimental effects on water quality and the health of living beings. The high affinity of poly(ionic liquid)s toward the target compounds as well as the magnetic behavior of Fe3 O4 were combined in this material to provide an efficient and simple magnetic solid-phase extraction approach. The adsorption behavior of the poly(ionic liquid)-bonded magnetic nanospheres was examined to optimize the synthesis. Different parameters affecting the magnetic solid-phase extraction of phenolic compounds were assessed in terms of adsorption and recovery. Under the optimal conditions, the proposed method showed excellent detection sensitivity with limits of detection in the range of 0.3-0.8 ng/mL and precision in the range of 1.2-3.3%. This method was also applied successfully to the analysis of real water samples; good spiked recoveries over the range of 82.5-99.2% were obtained.

Microwave-assisted synthesis of ionic liquid-modified silica as a sorbent for the solid-phase extraction of phenolic compounds from water

In this work, N-methylimidazolium ionic liquid-modified silica was synthesized using microwave irradiation. The modified silica was characterized by Fourier transform infrared analysis, elemental analysis, energy spectrum analysis, thermogravimetric analysis, and scanning electron microscopy. The synthesized material was used as a sorbent for the solid-phase extraction of four phenolic compounds from water. The extraction conditions including the type and consumption of eluent, the amount of sorbent, the pH, and the flow rate of the water samples were optimized. Satisfactory extraction recoveries were achieved using 200 mg of functionalized silica, 5 mL of methanol as eluent, a sample pH of 5, and a flow rate of 3 mL min−1. The analytes were separated and detected using high-performance liquid chromatography. Analyte recoveries were found to be between 88% and 102% under optimized conditions with a relative standard deviation of ≤7%. The method was successfully applied for the extraction of phenolic compounds from water samples, indicating that ionic liquid-functionalized silica cartridges performed better than bare silica cartridges in the extraction of these analytes.

Сорбционно-хроматографическое определение галловой, кофейной кислот, рутина и эпикатехина в лекарственных растениях

The sorption processes of solid-phase extraction of phenolic compounds from water extracts of medicinal herbs followed by chromatographic technique have been studied. Using model aqueous solutions and water extracts of Hypericum perforatum and Achillea millefolium the Diapak C18 recoveries overcome versus Diapak P (hypercross-linked polystyrene) and liquid-liquid extraction technique. The conditions of sorption extraction and determination of gallic acid, trans-caffeic acid and rutin using the sorbent Diapak C18 were optimized. Key words : solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), phenolic compounds, medicinal herbs (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.012 Z.A. Temerdashev, V.V. Milevskaya, N.V. Kiseleva, N.A. Vernikovskaya, V. А . Korobkov Kuban State University, Krasnodar, Russian Federation

Octadecyltrimethylammonium surfactant-immobilized cation exchange membranes for solid-phase extraction of phenolic compounds

In this study, octadecyltrimethylammonium surfactant was immobilized onto a cation exchange membrane for the application in solid-phase extraction of phenolic compounds. The results indicate that an HCl prewashing step and the use of hydroxide (or methoxide) counter ion could greatly improve the immobilized surfactant capacity. Through elemental and thermogravimetric analyses, the resulted immobilization percentage on the membrane (compared to membrane ion exchange capacity) was about 50, 100, and 150%, respectively, for the feed surfactant amount of 150, 2000, and 5000 μmol (volume = 20 mL). Phenol, 4-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, and bisphenol A were the tested compounds in a breakthrough volume experiment. The order of the obtained breakthrough volume values is similar to that of K ow values of the phenolic compounds. In the solid-phase extraction process from a feed mixture of 0.1 ppm for 4-nitrophenol, 2,4-dichlorophenol, and 4-chloro-3-methylphenol, high concentration factors and almost complete recoveries were achieved. Moreover, by increasing the membrane volume, a larger sample volume could be processed without any deterioration in performance.

The role of capacity factor in method development for solid-phase extraction of phenolic compounds. II

Recently, a simple method was developed for the determination of capacity factors of phenolic compounds on solid-phase extraction cartridges [ J. Chromatogr. A, 693 (1995) 217]. In the present paper the capacity factors determined by this method are used to predict recoveries of phenolic compounds in solid-phase extraction at three different sample volumes. The values are compared with those of recovery tests from both model solutions and spiked surface water samples. Based on calibration data the minimum sample concentrations which can be determined by the SPE procedure are also calculated from the capacity factors.

Comparative study of solid-phase extraction of phenolic compounds. Influence of the ion pair reagent

A comparative study of the solid phase extraction of phenolic compounds in water was carried out. Three different sorbents, C18, CH and PLRP-S, were tested for the preconcentration process in order to determine phenolic compounds in water at μg l−1 levels by reversed-phase LC separation and diode-array detection. The addition of an ion-pair reagent in the extraction process was also studied in order to increase the breakthrough volume of some compounds. Using the optimized conditions the limit of detection was less than 0.5 μg l−1, the maximum admissible concentration (MAC) in drinking water. The method was applied to determine phenolic compounds in Ebro river water however no phenols were found within the detection limits of the method.