Solid-phase Microextraction Of Phthalate Esters Research Articles

Quinoxaline core-conjugated microporous polymer coating for highly sensitive solid-phase microextraction of phthalate esters in liquid food samples

Quinoxaline core-conjugated microporous polymer coating for highly sensitive solid-phase microextraction of phthalate esters in liquid food samples

Ethane-bridge periodic mesoporous organosilica materials as a novel fiber coating in headspace solid-phase microextraction of phthalate esters from saliva and PET container samples.

The current study presents a periodic mesoporous organosilica (PMO) with a high surface area and uniform-porosity material. The PMO materials were successfully synthesized and modified. The resultant material was characterized by different characterization techniques. The prepared PMO was immobilized on a stainless steel wire surface and was evaluated for headspace solid-phase microextraction of the ultra-trace amount of phthalate esters from saliva and polyethylene terephthalate containers which were in contact with hot and cold water. Separation and determination of the phthalate esters (PEs) were performed by the GC-FID and GC-MS instruments. The key parameters affecting the extraction efficiencies, including extraction temperature, extraction time, ionic strength, and desorption temperature and time, were investigated and optimized. Under optimum conditions, the repeatability for one fiber (n = 7) was 4.8-8.7%, and fiber-to-fiber reproducibility (n = 3) was 7.5-10.6% for the extracted compounds. The limits of detection of the developed method for the studied compounds were between 0.01 and 1μg L-1. The results showed suitable coefficients of determination (R2 ≥ 0.99) for all of the analytes in the 0.05-300μg L-1 calibration range. Acceptable recovery values of 91-107%, 82-110%, and 98-104% were obtained in saliva, polyethylene terephthalate containers hot water, and cold water, respectively.

Biopolymer-imidazolium based dicationic ionic liquid modified clay bionanocomposite coating for solid-phase microextraction of phthalate esters

In this study, biopolymer-ionic liquid modified clay bionanocomposite was used as a coating for solid phase microextraction fiber to improve the analysis of plasticizers. Montmorillonite (MMT) clay intercalated with carboxymethyl cellulose (CMC) and dicationic imidazolium-based ionic liquid (Im-DIL) was coated onto an etched and hydroxyl functionalized stainless steel wire. The prepared MMT/CMC/Im-DIL coated fiber was assessed for the determination of six phthalate esters (PAEs) using direct immersion solid-phase microextraction (DI-SPME) with gas chromatography/mass spectrometer (GC/MS). Compared to MMT, MMT/CMC, MMT/Im-DIL, MMT/CMC/Im-DIL coating displayed much better extraction performance (>nearly 486–20 times). Under optimized conditions, the proposed method performed wide linearity (0.01–400.0 µg L-1), low limit of detection (1.0 ng L-1), satisfactory extraction repeatability (RSD%, ⩽ 3.86) and preparation repeatability (RSD%, ⩽ 5.79). The proposed method was applied successfully for analyzing of PAEs in beer, mineral water and carbonated lemonade drink.

Solid-Phase Microextraction of Phthalate Esters from Aqueous Media by Functionalized Carbon Nanotubes (Graphene Oxide Nanoribbons) and Determination by GC–FID

Multiwalled carbon nanotubes were exposed to hydrothermal treatment for obtaining graphene oxide nanoribbons (GONRs). The fabricated graphene oxide nanoribbons have been morphologically and compositionally characterized via FE-SEM, XRD, and FT-IR techniques. The as-synthesized GONRs have been used as sorbent phase for headspace solid-phase microextraction of phthalate esters (PEs) from aqueous solutions. In this regard, the GC–FID analysis route has been used for quantification of PEs. The new SPME fiber shows remarkable analytical figures of merit including broad dynamic linear ranges, low limits of detection, as well as good stability and reasonable relative standard deviations for evaluation of PEs. The linearity of the method for analysis of PEs including DnBP, DnPP, DEHP, DEHA, BBP, and DMP was between the range of 0.05–100, 0.05–100, 0.1–100, 0.1–100, 0.2–100, and 0.5–100 μg L−1, respectively. The limits of detection (based on S/N = 3) and correlation coefficients were found to be in the range of 0.02–0.2 μg L−1 and 0.9907–0.9952, correspondingly. The prepared GONR-coated SPME fiber shows larger extraction yield in comparison to pristine MWNTs and commercial PDMS SPME fibers. Furthermore, real sample analysis showed that there is no significant matrix effect for evaluation of PEs from environmental water samples and proposed method could be used for evaluation and determination of PEs from aqueous samples in a precise and accurate manner. The existence of functional groups, π–π interactions, as well as hydrogen bonding between adsorbent phase and PE analytes could be the reason for observing such a high extraction yield.

Copper ferrite nanoparticles as novel coating appropriated to solid-phase microextraction of phthalate esters from aqueous matrices

The prepared CuFe2O4 nanoparticles (NPs) resulting from a facile citrate–nitrate combustion method were adhesived on stainless steel wire with epoxy glue as a novel fiber coating. A direct immersion solid-phase microextraction (DI-SPME) method based on the prepared coating was established through sensitively detecting four phthalate esters (PAEs) from aqueous media with gas chromatography-flame ionization detection (GC-FID). The effects of various parameters on the efficiency of SPME process such as extraction time, extraction temperature, pH, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the limit of detections (LODs) and quantifications (LOQs) for the phthalate esters varied in the range of 0.12–0.40 μg·L−1 and 0.40–1.33 μg·L−1, respectively. The inter-day and intra-day relative standard deviations for these varied phthalate esters at 10 μg·L−1 concentration level (n = 6) using a single fiber were 3.9–12.4% and 6.6–15.1%, respectively. The fiber to fiber repeatabilities (n = 3), expressed as relative standard deviation (RSD%), were between 9.9% and 16.5% at 10 μg·L−1 concentration levell, and the the linear ranges varied between 1 and 500 μg·L−1. The prepared fiber can be repeatedly used to exceed 80 times, revealing a long lifetime and good stability. The method was successfully applied to analysis of the mineral water samples with recoveries from 81.1 to 103.7%. This work also provided an interesting insight for stable SPME fiber prepared by spinel materials for efficient extraction of PAEs.

Reduced graphene-decorated covalent organic framework as a novel coating for solid-phase microextraction of phthalate esters coupled to gas chromatography-mass spectrometry.

Schiff base network-1 (SNW-1), as a new generation of covalent organic frameworks (COFs), was synthesized and modified by fabrication of a composite with graphene oxide (GO). The fabricated nanocomposite was characterized with FT-IR spectroscopy, XRD, FE-SEM, EDX, TGA, and the nitrogen adsorption-desorption technique. Characterization results showed that SNW-1 can reduce GO during the fabrication procedure and produce an effective and stable nanocomposite. This nanocomposite was deposited on the surface of a stainless steel wirevia a single phase inversion method with the help of polyethersulfone, as a porous adhesive material. This robust and stable coating was used for head space solid-phase microextraction of phthalate esters (PhEs) from water samples. Determination of the PhEs was performed with gas chromatography coupled to mass spectrometry. SNW-1 is N-rich, and reduced-GO is full of hexagonal conjugated rings. Therefore, due to hydrogen binding and π-interaction, the coating has a high tendency to PhEs. Effective adsorption and desorption parameters were optimized. The performance of the method was evaluated in terms of linear ranges (LRs from 0.05 to 100μgL-1 with R2 ≥ 0.9942) and limits of detection (LODs in the range of 0.01-0.50μgL-1). The average repeatability and fiber-to-fiber reproducibility were 6.8% and 9.2%, respectively. The method was employed to trace determination of PhEs in drinking water and pickled cucumber solution with good recovery (80.5-111.0%) and reliable reproducibility (5.5-9.5%). Graphical abstract Schematic representation of headspace-solid phase microextraction (HS-SPME) of phthalate esters (PhEs) from pickled cucumber solution and determination with gas chromatography-mass spectrometry (GC-MS).

An electrodeposited terephthalic acid-layered double hydroxide (Cu-Cr) nanosheet coating for in-tube solid-phase microextraction of phthalate esters.

A CuCr-layered double hydroxide nanosheet intercalated with terephthalic acid (TPA/LDH) was introduced as a coating for the in-tube solid phase microextraction (IT-SPME). The coating was placed on the inner surface of a stainless steel tube by using two-electrode electrodeposition. The sorbent was characterized by X-ray diffraction, scanning electronic microscopy, and Fourier transform infrared spectroscopy. The TPA/LDH coating, compared to a nitrate-LDH coating, exhibits enhanced extraction efficiency, long lifetime, good mechanical stability, and a large specific surface. The method was used for the extraction, preconcentration, and subsequent HPLC-based determination of dimethyl phthalate (DMP), dibutyl phthalate (DBP), diallyl phthalate (DAP), and diethylhexyl phthalate (DEHP). The effects of pH value of the solution, salt concentration, extraction and desorption conditions, and the effect of the alcohol content of the solution on the extraction efficiency were optimized. Under optimal conditions, the response is linear in the 0.05 to 1000μgL-1 ester concentration range, and the limits of detection (at S/N = 3) range between 0.01 to 0.1μgL-1. The inter- and intra-assay precisions (RSD%, for n = 3) range from 3.8 to 6.8% and from 3.5 to 5.7%, respectively. The method was successfully applied to the determination of four phthalate esters in different beverage samples. Graphical abstractA CuCr-layered double hydroxide nanosheet intercalated with terephthalic acid was used as a coating for in-tube solid phase microextraction of some phthalate esters from beverage samples.

Magnesium/aluminum-layered double hydroxide modified with hydrogen peroxide as a novel fiber coating for solid-phase microextraction of phthalate esters in aqueous samples

A novel coating material for solid-phase microextraction (SPME) was synthesized by treating magnesium/aluminum-layered double hydroxide (Mg/Al-LDH) with hydrogen peroxide in the presence of potassium iodide and was confirmed to be chemically and thermally stable. A direct immersion solid-phase microextraction method to determine phthalate esters (PAEs) in aqueous samples was developed using the constructed fiber coating to couple with gas chromatography. Several factors on SPME procedure were investigated in detail. Under the optimized conditions, the linear ranges of the developed method were between 1 and 500 μg L−1. The limits of detection and the limits of quantification for various phthalates were in the range of 0.42–1.29 μg L−1 and 1.40–4.13 μg L−1, respectively. The run-to-run RSD (n = 5) and the fiber-to-fiber RSD (n = 3) were 8.30–20.0% and 8.50–20.4%, respectively. This method was successfully applied to the analysis of PAEs from Yangtze River water samples and bottled mineral samples.

Electrochemical preparation of zinc oxide/polypyrrole nanocomposite coating for the highly effective solid-phase microextraction of phthalate esters.

In this work, zinc oxide/polypyrrole nanocomposite coating was fabricated on stainless steel and evaluated as a novel headspace solid-phase microextraction fiber coating for extraction of ultra-trace amounts of environmental pollutants, namely, phthalate esters, in water samples. The fiber nanocomposite were prepared by a two-step process including the electrochemical deposition of polypyrrole on the surface of stainless steel in the first step, and electrochemical deposition of zinc oxide nanosheets in the second step. Porous structure together with zinc oxide nanosheets with the average diameter of 30nm were observed on the surface by using scanning electron microscopy. The effective parameters on extraction of phthalate esters (i.e., extraction temperature, extraction time, desorption temperature, desorption time, salt concentration, and stirring rate) were investigated and optimized by one-variable-at-a-time method. Under optimized conditions (extraction temperature, 90°C; extraction time, 40min; desorption temperature, 270°C; desorption time, 5min; salt concentration, 25% w/v; and stirring rate, 1000rpm), the limits of detection were in the range of 0.05-0.8μg/L, and the repeatability and fiber-to-fiber reproducibility were in the ranges of 6.1-7.3% and 8.7-10.2%, respectively.

Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents

In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2–99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5–100.8% (<3.7% RSDs), 77.2–97.6% (<5.6% RSDs) and 75.5–99.7% (<6.2% RSDs), respectively. The developed AC-poly(STY-DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%–104.6% (<5.5% RSDs).

Electropolymerization of carbon nanotubes/poly-ortho-aminophenol nanocomposite on a stainless steel fiber for the solid-phase microextraction of phthalate esters

A nanoporous composite film of poly-o-aminophenol (PoAP) and oxidized multiwalled carbon nanotubes (MWCNTs), which is electrochemically co-deposited on a stainless steel wire, has been synthesized. It was used as a new coating for direct immersion solid-phase microextraction (DI-SPME) of phthalate esters in various aqueous samples. In order to obtain an adherent, smooth and stable film, experimental parameters related to the coating process were optimized. These parameters include mode of electropolymerization, potential range, scan rate, the number of cycles, concentration of the monomer and oxidized MWCNTs. The coating was highly stable and extremely adherent to the surface of the steel fiber. The effects of various parameters on the efficiency of the SPME process consisting of desorption temperature, desorption time, extraction time, extraction temperature, ionic strength and pH were also studied. Under optimized conditions, detection limits for the phthalate esters varied between 0.03 and 0.08 ng mL−1. The intra-day and inter-day relative standard deviations for various phthalate esters at 1.0 ng mL−1 concentration level (N = 7) using a single fiber were 4.1–11.1% and 4.6–12.5%, respectively. The fiber-to-fiber RSD% (N = 3) was 6.5–13.1% at 1.0 ng mL−1. The method was linear at three orders of magnitude with correlation coefficients varying from 0.9878 to 0.9995. The method was successfully applied to the analysis of bottled mineral water samples and three injectable infusion solutions with recoveries from 91 to 115%.

Solid-phase microextraction of phthalate esters from aqueous media by electrophoretically deposited TiO2 nanoparticles on a stainless steel fiber

A novel SPME fiber was prepared by electrophoretic deposition of titanium dioxide nanoparticles (nano-TiO2) on a stainless steel wire. It was used in the direct immersion solid-phase microextraction (DI-SPME) of four phthalate esters from aqueous samples prior to gas chromatographic (GC) analysis. The effects of various parameters on the efficiency of the SPME process such as the mode of extraction, extraction temperature, film thickness of the SPME fiber, salt content, extraction time and stirring rate were investigated. The comparison of the fiber with another homemade poly(3,4-ethylenedioxythiophene)-TiO2 (PEDOT-TiO2) nanocomposite fiber and a commercial polydimethylsiloxane (PDMS) fiber showed the better extraction efficiency of the nano-TiO2 fiber for phthalate esters. Under optimized conditions, the limit of detection (LOD) for the phthalate esters varied between 0.05 and 0.12μgL−1. The inter-day and intra-day relative standard deviations for various phthalate esters at 10μgL−1 concentration level (n=6) using a single fiber were 6.6–7.5% and 8.3–11.1%, respectively. The fiber to fiber repeatabilities (n=4), expressed as relative standard deviation (RSD%), were between 8.9% and 10.2% at 10μgL−1 concentration level. The linear ranges varied between 0.5 and 1000μgL−1. The method was successfully applied to the analysis of the bottled mineral water sample with recoveries from 86 to 107%.

Solid-phase microextraction of phthalate esters from aqueous media by electrochemically deposited carbon nanotube/polypyrrole composite on a stainless steel fiber

A novel direct immersion solid-phase microextraction (DI-SPME) method using a stainless steel wire electrochemically coated with oxidized multiwalled carbon nanotubes–polypyrrole composite (MWCNTs–PPy) was used in the gas chromatographic (GC) determination of phthalate esters in aqueous samples. The composite coating did not swell in organic solvents nor did it strip off from the substrate. It was also highly stable and extremely adherent to the surface of the steel fiber. The effects of various parameters on the efficiency of SPME process such as extraction time, extraction temperature, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the detection limits for the phthalate esters varied between 0.05 and 0.1 ng mL −1, the inter-day and intra-day relative standard deviations for various phthalates at 1.0 ng mL −1 concentration level ( N = 7) using a single fiber were 6.2–10.2% and 7.7–10.5, respectively. The fiber-to fiber RSD% ( N = 3) was 9.3–12.1% at 10 ng mL −1. The linear ranges varied between 0.5 and 300 ng mL −1. The method was successfully applied to the analysis of mineral water samples with the recoveries from 90 to 113%.

Comparison of different fibers for the solid-phase microextraction of phthalate esters from water

Solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC–MS) has been applied to determine six phthalate esters and one adipate ester in water. The SPME parameters were optimized for several commercially available fibers. A 65-μm polydimethylsiloxane-divinylbenzene (PDMS-DVB) was the fiber selected and was applied to analysis of water from the Ebro river and the industrial port of Tarragona. The studied compounds were found at concentrations ranging from 0.4 μg l −1 for di- n-butyl phthalate ester (DnBP) to 3.2 μg l −1 for bis(2-ethylhexyl) phthalate ester (DEHP). The linear range for real samples was from 0.1 to 10 μg l −1 for most phthalates, and the limits of detection of the method were between 3 and 30 ng l −1. Repeatability and reproducibility between days ( n=5) for 1 μg l −1 samples were below 13 and 18%, respectively.