Solid-phase Extraction Of Phthalate Esters Research Articles

Magnetic covalent organic frameworks for rapid solid-phase extraction of phthalate esters and bisphenol A in beverage samples.

Phthalate esters (PAEs) and bisphenol A (BPA) are endocrine-disrupting chemicals (EDCs), which are widely used in the production of food plastic packaging and easily migrate to food. Continuous exposure to EDCs may cause harm to human health. Herein, magnetic covalent organic framework TFP-NDA/Fe3O4 was synthesized by magnetizing covalent organic framework TFP-NDA through a facile coprecipitation method, and used as an adsorbent for rapid solid-phase extraction of PAEs (diethyl phthalate (DEP), diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP)) and BPA. The extraction equilibrium can be reached within 12 min. By combination with a gas chromatography-flame ionization detector, the limits of detection were 0.7-2.3 μg L-1 and the linear ranges were 10-500 μg L-1 for diethyl phthalate (DEP) and 10-1000 μg L-1 for diisobutyl phthalate (DIBP), dibutyl phthalate (DBP) and BPA with R2 > 0.9916. In beverage samples (plastic bottled drinking water, juice and carbonated drink), the developed method was successfully applied to extract and quantify PAEs and BPA with recoveries ranging from 81.7% to 114.2%.

Magnetic solid-phase extraction of phthalate esters from environmental water samples using fibrous phenyl-functionalized Fe3O4@SiO2@KCC-1

A new kind of phenyl-functionalized magnetic fibrous mesoporous silica (Fe3O4@SiO2@KCC-1-phenyl) was prepared by copolymerization as an efficient adsorbent for the magnetic extraction of phthalate esters from environmental water samples. The obtained Fe3O4@SiO2@KCC-1-phenyl showed monodisperse fibrous spherical morphology, fairly strong magnetic response (29 emu/g), and an abundant π-electron system, which allowed rapid isolation of the Fe3O4@SiO2@KCC-1-phenyl from solutions upon applying an appropriate magnetic field. Several variables that affect the extraction efficiency of the analytes, including the type of the elution solvent, amount of adsorbent, extraction time and reusability, were investigated and optimized. Under optimum conditions, the Fe3O4@SiO2@KCC-1-phenyl was used for the extraction of four phthalate esters from environmental water samples followed by high-performance liquid chromatographic analysis. Validation experiments indicated that the developed method presented good linearity (0.1–20 ng/mL), low limit of detection (7.5–29 µg/L, S/N =3). The proposed method was applied to the determination of phthalate esters in different real water samples, with relative recoveries of 93%−103.4% and relative standard deviation of 0.8%–8.3%.

Preparation of magnetic zeolitic imidazolate framework-67 composites for the extraction of phthalate esters from environmental water samples

In this paper, magnetic ZIF-67 composites were prepared by an in situ method and utilized in the magnetic solid-phase extraction of phthalate esters. The obtained magnetic ZIF-67 composites were characterized in detail, and the adsorption performance was evaluated. The results showed that ZIF-67 crystals in the composites had a chamfered cubic shape with about 2.0 μm diameter and Fe3O4 was attached on the surface of ZIF-67. The parameters affecting magnetic solid-phase extraction efficiency were optimized including the adsorption and desorption conditions. Under the optimum conditions, magnetic solid-phase extraction coupled with gas chromatography-mass spectrometry for analyzing seven phthalate esters in environmental water samples was established. All the analytes exhibited good linearity (1-200 ng mL-1) with correlation coefficients higher than 0.9950. The relative standard deviations were between 4.3% and 8.9%. The developed method showed high sensitivity and had good potential for analyzing trace phthalate esters in water samples.

Preparation of carboxylatocalix[4]arene functionalized magnetic polyionic liquid hybrid material for the pre-concentration of phthalate esters

In this work, we designed a novel hybrid material based on the polymerization of an ionic liquid on a magnetic core and further functionalized with carboxylatocalix[4]arene. Scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, thermal gravimetric-derivative thermogravimetric analysis, energy dispersive X-ray spectroscopy, X-ray diffractometer, and vibrating sample magnetometer were utilized to examine the physicochemical properties of the hybrid material obtained. The material was used as the adsorbent for magnetic solid-phase extraction of phthalate esters. To obtain the maximum pre-concentration efficiency, a series of parameters influencing the extraction efficiency, including sample pH, adsorbent amount, adsorption time, eluent type as well as salt addition, was examined systematically. Under the optimum conditions, a fast and feasible pre-concentration protocol for phthalate esters was established with satisfactory enrichment factors between 158.7 and 191.3. The limits of detection from high-performance liquid chromatographic analysis for the target analytes were in the range of 0.02–0.31 ng mL―1. The wide linear ranges varying from 0.1 to 100 ng mL―1 were achieved with correlation coefficients greater than 0.9977. To evaluate the feasibility of this method, it was successfully applied to analyse phthalate esters in multiple kinds of real samples including tap water, lake water, drinks, tonic lotions, and human serum samples. The results obtained demonstrated that the synthesized magnetic material had potential as a candidate in the pre-concentration field for phthalate esters due to the special properties stemming from its structure and components.

Dispersive magnetic solid-phase extraction of phthalate esters from water samples and human plasma based on a nanosorbent composed of MIL-101(Cr) metal-organic framework and magnetite nanoparticles before their determination by GC-MS.

In this study, a magnetic metal-organic framework was synthesized simply and utilized in the dispersive magnetic solid-phase extraction of five phthalate esters followed by their determination by gas chromatography with mass spectrometry. First, MIL-101(Cr) was prepared hydrothermally in water medium without using highly corrosive hydrofluoric acid, utilizing an autoclave oven heat supply. Afterward, Fe3 O4 nanoparticles were decorated into the matrix of MIL-101(Cr) to fabricate magnetic MIL-101 nanocomposite. The nanocomposite was characterized by various techniques. The parameters affecting dispersive magnetic solid-phase extraction efficiency were optimized and obtained as: a sorbent amount of 15mg; a sorption time of 20min; an elution time of 5min; NaCl concentration, 10% w/v; type and volume of the eluent 1mL n-hexane/acetone (1:1 v/v). Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.08-0.15 and 0.5-200μg/L, respectively. The intra- and interday RSD% values were obtained in the range of 2.5-9.5 and 4.6-10.4, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the model analytes in water samples, and human plasma in the range of microgram per liter and satisfactory results were obtained.

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 0.02-0.03ng/mL for the water samples and 0.03-0.15ng/mL for the sports beverage sample. The limits of quantitation (S/N=9) for the analytes were 0.06-0.09ng/mL for water samples and 0.09-0.45ng/mL for sports beverage sample. The calibration curves for the phthalate esters by the method had a good linearity from 0.1 to 80.0ng/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%.

Ionic liquid enhanced magnetic solid-phase extraction of phthalate esters in food samples with oleic acid coated-Fe3O4 nanoparticles prior to HPLC

ABSTRACTA novel method based on ionic liquid enhanced magnetic solid-phase extraction (MSPE) coupled with high-performance liquid chromatography (HPLC) for the separation/analysis of phthalate esters (PAEs) in food samples was established. 1-hexyl-3-methylimidazoliu-hexafluorophosphate ([C6MIM][PF6]) was used to coat oleic acid Fe3O4 nanoparticles with core–shell structures to prepare MSPE agents (Fe3O4@OA@IL). The main parameters affecting the extraction efficiency of PAEs were studied. Under the optimal conditions, the calibration curves were linear in the range of 5–5000 ng mL−1 (R2 = 0.9972–0.9998) of four PAEs. The limit of detections (LODs) and relative standard deviations (RSDs, n = 5) of the method were 1.27–2.95 ng mL−1 and 3.9–5.3%, respectively.

Synthesis of molecularly imprinted polymers by atom transfer radical polymerization for the solid-phase extraction of phthalate esters in edible oil.

Novel molecularly imprinted polymers of phthalate esters were prepared by atom transfer radical polymerization using methyl methacrylate as functional monomer, cyclohexanone as solvent, cuprous chloride as catalyst, 1-chlorine-1-ethyl benzene as initiator and 2,2-bipyridyl as cross-linker in the mixture of methanol and water (1:1, v/v). The effect of reaction conditions such as monomer ratio and template on the adsorption properties was investigated. The optimum condition was obtained by an orthogonal experiment. The obtained polymers were characterized using scanning electron microscopy. The binding property was studied with both static and dynamic methods. Results showed that the polymers exhibited excellent recognition capacity and outstanding selectivity for ten phthalate esters. Factors affecting the extraction efficiency of the molecularly imprinted solid-phase extraction were systematically investigated. An analytical method based on the molecularly imprinted coupled with gas chromatography and flame ionization detection was successfully developed for the simultaneous determination of ten phthalate esters from edible oil. The method detection limits were 0.10-0.25 μg/mL, and the recoveries of spiked samples were 82.5-101.4% with relative standard deviations of 1.24-5.37% (n = 6).

Magnetic solid-phase extraction of phthalate esters (PAEs) in apparel textile by core–shell structured Fe3O4@silica@triblock-copolymer magnetic microspheres

In this paper, novel core–shell structured magnetic Fe3O4/silica nanocomposites with triblock-copolymer grafted on their surface (Fe3O4@SiO2@MDN) were successfully fabricated by combining a sol–gel method with a seeded aqueous-phase radical copolymerization approach. Owing to the excellent characteristics of the strong magnetic responsivity, outstanding hydrophilicity and abundant π-electron system, the obtained core–shell structured microspheres showed great potential as a magnetic solid phase extraction (MSPE) adsorbent. Several kinds of phthalate esters (PAEs) were selected as model analytes to systematically evaluate the applicability of adsorbents for extraction followed by gas chromatography–mass spectrometry (GC–MS) analyses. Various parameters, including adsorbents amounts, adsorption time, species of eluent, and desorption time were optimized. Under the optimized conditions, Validation experiments such as recovery, reproducibility, and limit of detection were carried on and showed satisfactory results. The analysis method showed excellent linearity with a wide range of 0.2–10mg/kg (R2>0.9974) and low limits of detection (LOD) of 0.02–0.09mg/kg (S/N=3). Ultimately, the novel magnetic adsorbents were successfully employed to detect the PAEs in apparel textile samples. And the results indicated that this novel approach brought forward in the present work offered an attractive alternative for rapid, efficient and sensitive MSPE for PAEs compounds.

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.

Application of magnetic graphitic carbon nitride nanocomposites for the solid-phase extraction of phthalate esters in water samples.

Magnetic graphitic carbon nitride nanocomposites were successfully prepared in situ and used to develop a highly sensitive magnetic solid-phase extraction method for the preconcentration of phthalate esters such as di-n-butyl phthalate, butyl phthalate, dihexyl phthalate, and di-(2-ethyl hexyl) phthalate from water. The adsorption and desorption of the phthalate esters on magnetic graphitic carbon nitride nanocomposites were investigated and the parameters affecting the partition of the phthalate esters, such as adsorption, desorption, recovery, were assessed. Under the optimized conditions, the proposed method showed excellent sensitivity with limits of detection (S/N = 3) in the range of 0.05-0.1 μg/L and precision in the range of 1.1-2.6% (n = 5). This method was successfully applied to the analysis of real water samples, and good spiked recoveries over the range of 79.4-99.4% were obtained. This research provides a possibility to apply this nanocomposite for adsorption, preconcentration, or even removal of various carbon-based ring or hydrophobic pollutants.

Investigation of feasibility of bamboo charcoal as solid-phase extraction adsorbent for the enrichment and determination of four phthalate esters in environmental water samples

This paper demonstrates, for the first time, that adsorptive potential of bamboo charcoal for solid-phase extraction of phthalate esters was investigated. The four phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP) and di- n-butyl phthalate (DBP), are quantitatively adsorbed on a bamboo charcoal packed cartridge, then the analytes retained on the cartridge are quantitatively desorbed with optimum amounts of acetone. Finally, the analytes in the eluant acetone are determined by high-performance liquid chromatography-ultraviolet detectior. Important parameters influencing the extraction efficiency, such as eluant and its volume, flow rate of sample, sample volume, pH, the amount of adsorbent and ionic strength were investigated and optimized in detail. Under the optimum conditions, the limits of detection were 0.35–0.43 μg/L for four phthalate esters. The proposed method has been applied to the analysis of rainwater and tap water samples. And satisfactory spiked recoveries were obtained in the range of 75.0–114.2%. All the results indicated that the bamboo charcoal has great potential as a novel adsorbent material for the enrichment and determination of phthalate esters in real environmental water samples.

Cetyltrimethylammonium bromide-coated titanate nanotubes for solid-phase extraction of phthalate esters from natural waters prior to high-performance liquid chromatography analysis

As a novel nanomaterial, titanate nanotube has attracted considerable attention recently. However, most of the research work is focused on the preparation of this nanomaterial, and there is lack of information about its application in the fields of environmental monitoring and analytical chemistry. The purpose of our study is to investigate the feasibility of titanate nanotubes as an adsorbent for solid-phase extraction of several phthalate esters. The titanate nanotubes in this study were prepared by alkaline hydrothermal method. The cationic surfactant cetyltrimethylammonium bromide (CTAB)-titanate nanotube system was adopted based on hemimicelles/admicelles formed on the mineral oxide surface. It was shown in the batch experiment that the highest adsorption of phthalate esters onto the CTAB-titania and -titanate nanotube system occurred when the CTAB was varied from 100 to 200 mg g −1 titania or 80 to 300 mg g −1 titanate nanotube separately. According to the fluorescent spectra of a molecular probe, N-phenyl-1-naphthylamine, and the binding constant of solute in CTAB admicelles, the CTAB-titanate nanotube admicelles was more hydrophobic than CTAB-titania admicelles. Consequently, CTAB-titanate nanotube admicelles system was suitable for concentrating phthalates esters in water. An admicelle column was prepared with 100 mg of titanate nanotubes by passing through 100 mg g −1 titanate nanotube of CTAB. And excellent collection yields were obtained for all the analytes when the sample volume was up to 1000 mL. Under the optimal conditions, the detection limits found for di- n-propyl-phthalate, di- n-butyl-phthalate, di-cyclohexyl-phthalate, and di- n-octyl-phthalate were 39, 19, 35 and 20 ng L −1, respectively. The developed method was successfully applied to the analysis of several real water samples and satisfactory recoveries were achieved. All the results indicated the application potential of titanate nanotubes as solid-phase extraction adsorbents to pre-treat water samples.