Trace Estrogens Research Articles

Novel ferrofluid based on hydrophobic deep eutectic solvents for separation and analysis of trace estrogens in environmental water and urine samples.

A novel ferrofluid prepared from ahydrophobic deep eutectic solvent (DES) and Fe3O4@graphite composite materials was introduced as a green microextraction medium for the separation and enrichment of trace estrogens in real samples. It was found that the ferrofluid greatly improved the capacity and selectivity of target analytes, benefiting from the enrichment of both DES and Fe3O4@graphite composite materials. Using a combination of high-performance liquid chromatography-fluorescence detection (HPLC-FLD) and vortex-assisted liquid-liquid microextraction (VALLME), a new method was established for simultaneous rapid processing and accurate determination of three estrogens (estradiol [E2], estriol [E3], and ethinyl estradiol [EE2]) in environmental water and urine samples. Key parameters affecting the extraction efficiency were optimized using a single-factor approach and response surface methodology. Under optimal conditions, this method yielded a low limit of detection (1.01 ng L-1, 3.03 ng L-1, and 25.0 ng L-1 for EE2, E2, and E3, respectively), wide linear range (3-200,000ng L-1), high enrichment factors (9.81-47.2), and satisfactory recovery (73.8-129.0%). Compared with traditional analytical techniques, this method avoids the use of volatile toxic organic extraction solvents and cumbersome phase separation operations.

3D printed stir bar sorptive extraction coupled with high performance liquid chromatography for trace estrogens analysis in environmental water samples

BackgroundAny imaginary shape with good preparation reproducibility can be made by 3D printing technology, and it has been applied in various fields. Comparatively, its applications in sample pre-treatment are relatively less, most of which involves making extraction sorbents and producing non-functionalized devices for support assistance. 3D printing has not been applied to fabricate stir bars in stir bar sorptive extraction, mainly due to the lacking of suitable printing feedstocks. This work aimed to fabricate stir bars by 3D printing, reducing the manufacturing cost and steps and improving preparation reproducibility. (90) ResultsBy using fused deposition modeling technique and porous filament printing feedstock, stir bars were fabricated without any modifications. Adsorption performance of 3D printed stir bars were investigated for substances with different structures and polarities. Five estrogens with adsorption efficiencies of over 80 % were selected as the representatives. The 3D printed stir bars exhibited good preparation reproducibility (2.9–4.4 %) and higher extraction recoveries (73–81 %) for five estrogens than commercial polydimethylsiloxane coated stir bars (13–69 %) in a shorter time (90 vs 120 min). They showed long lifespan (160 times) with good mechanical properties and merited reduced manufacturing cost (0.064 $ per bar) and manual operation. A method of stir bar sorptive extraction coupled with high performance liquid chromatography was proposed for trace analysis of estrogens in environmental water. Under the optimized conditions, the linear ranges for estrogens were 0.5–200 μg/L with LODs of 0.13–0.17 μg/L. (136) SignificanceThe feasibility of fused deposition modeling in stir bar fabrication was demonstrated, along with the potential of porous filament printing feedstock as the sorbent for substances with medium polarity. 3D printed stir bars were featured with excellent preparation reproducibility, long lifespan, and good mechanical properties. The stir bar fabrication method can be used for mass production with minimal differences in products performance. (62)

Cyano-functionalized ionic porous polymer: A novel adsorbent for effectively enriching trace estrogens in water and milk

Estrogens have been recognized as a class of endocrine disruptors. It is of utmost significance to develop a sensitive analytical method for the reliable determination of estrogen in environmental and food samples. Herein, a series of cyano-functionalized ionic porous organic polymers (CN-iPOPs) were successfully prepared for the first time using (1-imidazolyl)acetonitrile and biphenyl dichlorobenzene as building blocks via Friedel-Crafts alkylation reaction. The optimized CN-iPOPs (CN-iPOP3) displayed exceptional sorption capacity for estrogens, making it an advanced adsorbent for solid phase extraction (SPE) of estrogens. In combination, CN-iPOP3 based SPE with high performance liquid chromatography, a sensitive and reliable method was developed for determination of four estrogens in lake water and milk samples. Under optimal conditions, good linear response was obtained to be 0.09–100.0 ng mL−1 for lake water and 0.90–1000.0 ng mL−1 for milk, with detection limits (S/N = 3) of 0.03–0.05 ng mL−1 and 0.30–0.70 ng mL−1 respectively. The method recoveries were in the range of 85.0%-119.0% with the relative standard deviations lower than 7.8%. The synergistic effect of electrostatic force, hydrogen bond, π-π stacking interaction and hydrophobic interaction was proved to be the main adsorption mechanism. This research provides a promising approach to design iPOP-based adsorbents for effectively enriching or removing organic pollutants.

Methacrylate bonded covalent organic framework monolithic column online coupling with high-performance liquid chromatography for analysis of trace estrogens in food

Covalent organic frameworks (COFs) are a burgeoning class of crystalline porous materials with unique properties and have been considered as a promising functional extraction medium in sample pretreatment. In this study, a new methacrylate-bonded COF (TpTh-MA) was well designed and synthesized via the aldehyde-amine condensation reaction, and the TpTh-MA was incorporated into poly (ethylene dimethacrylate) porous monolith by a facile polymerization reaction inside capillary to prepare a novel TpTh-MA monolithic column. The fabricated TpTh-MA monolithic column was characterized with scanning electron microscope, Fourier transform infrared spectrometer, X-ray diffraction, and N2 adsorption–desorption experiments. Then, the homogeneous porous structure, good permeability and high mechanical stability of TpTh-MA monolithic column was used as separation and enrichment media of capillary microextraction, which was coupled with high-performance liquid chromatography fluorescence detection for online enrichment and analysis of trace estrogens. The main experimental parameters influencing the extraction efficiency were systematically investigated. The adsorption mechanism for three estrogens was also explored and discussed based on hydrophobic effect, π-π affinity and hydrogen bonding interaction, which contributed to its strong recognition affinity to target compounds. The enrichment factors of the TpTh-MA monolithic column micro extraction method for the three estrogens were 107–114, indicating a significant preconcentration ability. Under optimal conditions, a new online analysis method was developed and exhibited good sensitivity and wide linearity range of 0.25–100.0 µg·L-1 with a coefficient of determination (R2) higher than 0.9990 and a low limit of detection with 0.05–0.07 µg·L-1. The method was successfully applied for online analysis of three estrogens of milk and shrimp samples and the recoveries obtained from spiking experiments were in range of 81.4–113% and 77.9–111%, with the relative standard deviations of 2.6–7.9% and 2.1–8.3% (n = 5), respectively. The results revealed the great potential for the application of the COFs-bonded monolithic column in the field of sample pretreatment.

Determination of Environmental Estrogens by Polybenzothiophene-based Solid-phase Extraction (SPE) and High-Performance Liquid Chromatography (HPLC)

Porous polybenzothiophene was synthesized using Friedel-Crafts alkylation and applied as a sorbent for phase extraction. In combination with high performance liquid chromatography, a method for the simultaneous determination of the estrogens 17β-estradiol, ethinylestradiol, and diethylstilbestrol was established for environmental samples. Under the optimized conditions, satisfactory linearity was obtained from 2.0 to 1000.0 μg/L with the coefficients of determination (R2) exceeding 0.9977. The limits of detection were less than 0.3 μg/L for all targets, and the relative standard deviations (n = 5) were below 6.7%. The developed procedure was applied for the determination of estrogens in lake water, grass carp, and chicken manure. The recoveries of the targets were from 75.3% to 106.7%, 78.8% to 109.6%, and 89.1% to 114.5%, respectively. Ethinylestradiol was detected in lake water at 5.3 μg/L. None of the target compounds were present in the grass carp. Ethinylestradiol and diethylstilbestrol were observed in chicken manure at 0.9 μg/g and 0.6 μg/g. The developed method was simple and efficient for the determination of trace estrogens in complex samples.

A molecularly imprinted fiber array solid-phase microextraction strategy for simultaneous detection of multiple estrogens.

A kind of selective enrichment material based on a homemade molecularly imprinted polymer (MIP) fiber array with high adsorption capacity was developed for the accurate analysis of estrogens in food samples. Here, the MIP with 17β-estradiol as the template was obtained by in situ polymerization. The chemical composition, morphologies, surface area, and pore size of the polymer were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer-Emmett-Teller theory. The extraction time, desorption solvent, desorption time, ionic strength, and the pH of solution were investigated to ascertain the best extraction conditions. Under the optimal extraction conditions, three fiber coatings of 17β-estradiol MIP and commercial polyacrylate (PA) were bound to a homemade handle to assemble the fiber array, respectively. The findings showed that the three-fiber array of the MIP significantly improved the extraction capacity by 145 times compared to PA. The MIP fiber array showed high adsorption capacity for the template molecule 17β-estradiol and its structural analogues estrone, bisphenol F, bisphenol B, and bisphenol A, with enrichment factors of 99.60-133.16. A molecularly imprinted polymer solid-phase microextraction fiber array (MIP-SPME fiber array) coupled with high-performance liquid chromatography-diode array detection was used for the analysis and detection of the five estrogens in milk and yogurt samples. Satisfactory recoveries were achieved ranging from 74.75-119.41% with <9.42% relative standard deviations. The developed method for the simultaneous determination of trace estrogens in food samples exhibited a limit of detection of 0.33 μg L-1. The MIP-SPME fiber array provided an available strategy for improving the selectivity and adsorption capacity of SPME for trace target component analysis in complex matrices and increasing the sensitivity of the analytical method.

Porous capillary monolithic column coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry for fast and effective separation and determination of estrogens

In this work, a porous capillary monolithic column was simply prepared by in situ thiol-alkyne click polymerization of dipentaerythritol hexakis (3-mercaptopropionate) and dimethyl dipropargylmalonate in fused-silica capillary. The capillary monolithic column shows excellent permeability, high porosity, and thoiether-rich groups, thereby, a high-efficient capacity for trace estrogens from complex samples are obtained via electron-donor-acceptor π-π interaction and hydrophobic interaction. The highest adsorption efficiency for estrogens is achieved at pH = 7.0 with a flow rate of 0.200 mL min−1. The superior adsorption capacities of the as-prepared capillary column for eight estrogens range from 0.092 mg m−1 to 0.31 mg m−1. A simple, reliable, and sensitive method for the determination of eight estrogens in biological and environmental samples is developed using the monolithic polymer as in-tube solid-phase microextraction coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS), and the total instrumental analysis time for the SPME-UPLC-MS/MS procedures was about 60 min per sample. The developed method shows a wide linear range (0.0500–5.00 μg L−1), and low limits of detection (5.34–9.63 ng L−1) for estrogens. The concentrations of estrogens in serum, urine, and pond water samples are found to be no more than 3.69, 0.741, and 1.04 μg L−1, respectively, and the satisfying recoveries for the eight estrogens range from 80.3% to 113% with relative standard deviations (n = 5) of 1.5–9.4%. The established method is highly potential for extraction and analysis of ultratrace target estrogens in complex matrices, such as biological and environmental samples.

Imine-linked porous covalent organic framework used for the solid-phase extraction of estrogens from honey prior to liquid chromatography-tandem mass spectrometry

以亚胺连接的多孔共价有机骨架材料(IL-COF-1)作为固相萃取的吸附剂,建立了液相色谱-串联质谱快速检测蜂蜜样品中痕量雌激素的方法。该研究选择雌二醇、己烯雌酚、雌三醇、β-雌二醇和炔雌醇5种雌激素作为目标分析物。在蜂蜜样品中添加雌激素,采用单因素优化法对影响萃取效果的重要因素进行优化,获得最佳条件:IL-COF-1用量为30 mg,样品流速为3 mL/min,样品溶液pH值为7,以5 mL的1%(v/v)氨水-甲醇溶液进行洗脱,流速为0.4 mL/min,萃取过程中不添加NaCl。采用高效液相色谱-三重四极杆质谱联用技术对提取物中的雌激素进行定量分析。以乙腈和5 mmol/L的乙酸铵溶液作为流动相进行梯度洗脱,经C18色谱柱分离,采用电喷雾离子源、质谱多反应监测和负离子扫描模式,实现了蜂蜜样品中5种雌激素的快速定性定量分析。在最佳条件下,方法验证结果中雌三醇、β-雌二醇和炔雌醇的线性范围为1~500 ng/g,雌二醇和己烯雌酚的线性范围为0.1~100 ng/g,相关系数(r)为0.9934~0.9972。检出限(S/N=3)为0.01~0.30 ng/g,定量限(S/N=10)为0.05~0.95 ng/g。添加50 ng/g 5种雌激素进行重复性实验,日内精密度相对标准偏差(RSD)为3.2%~6.6%,日间精密度RSD为4.2%~7.9%。基于IL-COF-1的固相萃取-液相色谱-串联质谱法具有快速准确、灵敏度高等特点,适用于蜂蜜中雌激素的分析和检测。将该方法应用于4个实际蜂蜜样品中雌激素的检测,均未检出目标物;在低中高3个水平下,5种雌激素的加标回收率为80.1%~115.2%,结果令人满意。

Magnetic polyimide nanosheet microspheres for trace analysis of estrogens in aqueous samples by magnetic solid-phase extraction-gas chromatography–mass spectrometry

Magnetic polyimide nanosheet microspheres (PI-NMs) were used for magnetic solid-phase extraction (MSPE) for the first time. The PI-NMs were modified with magnetic Fe3O4 nanoparticles by chemical coprecipitation to produce the PI-NM/Fe3O4 composite. The prepared composite possessed a nanosheet structure, large specific surface area (71.5 m2/g), high saturation magnetization (19.1 emu/g), large adsorption capacity (≥ 676 ng/mg for selected estrogens), and good extraction stability (> 10 times). Trace estrogens in environmental water and urine samples were extracted by the PI-NM/Fe3O4 composite, desorbed, derivatized, and analyzed by gas chromatography–mass spectrometry (GC-MS). The derivatization, extraction, and desorption conditions were optimized. Extraction equilibrium was achieved within 1 min due to the good dispersibility and large specific surface area of the PI-NM/Fe3O4 composite. Under the optimized conditions, the MSPE/GC–MS method validation results showed wide linearity (0.02–50 µg/L or 0.05–50 µg/L), high determination coefficients (R2 ≥ 0.9983), good intraday and interday precisions (expressed as relative standard deviation, RSDs ≤ 8.2%), and low limits of detection (LODs, 0.001–0.015 µg/L). For the real environmental water and urine samples, the recoveries and RSDs were 77.0–112.5% and 0.1–10.7%, respectively. The performance of the MSPE/GC–MS method proved that the PI-NM/Fe3O4 composite was a good alternative material for the extraction of organic pollutants in aqueous samples.

Preparation of porous polymers based on high internal phase emulsion for enrichment of estrogens in urine.

In this work, graphene oxide-hybridized high internal emulsion polymers with crosslinking and open-cell structure was prepared and applied for separation and enrichment of estrogens. The prepared graphene oxide-hybridized high internal emulsion polymer monoliths had hydrophobicity, porosity and stability, which were just obtained by one step in-situ emulsion polymerization of 2-ethylhexyl acrylate, glycidyl methacrylate, and divinylbenzene after doping with graphene oxide. Benefit from the advantages of its unique character, the graphene oxide-hybridized high internal emulsion polymers monolith with low background pressure (85kPa) and high mechanical strength could be applied for efficient separation for trace estrogens in urine. Under the optimized condition, trace estrogens, including estrone, estradiol, and diethylstilbestrol in urine, were detected by high-performance liquid chromatography, all the sample preparation process were carried out in 15min, the recovery rate was ranged from 85.0 to 106.0% and the relative standard deviation was less than 4.

Resorcinol-formaldehyde aerogel coating for in-tube solid-phase microextraction of estrogens.

Resorcinol-formaldehyde aerogel coating was in situ prepared on the surface of basalt fibers. The aerogel coating is uniformly modified onto basalt fibers, and it is very porous according to the characterization by using scanning electron microscopy. An extraction tube was prepared for in-tube solid-phase microextraction by placing the aerogel-coated basalt fibers into a polyetheretherketone tube. To evaluate the extraction performance toward five estrogenic compounds, the tube was connected with high performance liquid chromatography, the important extraction and desorption conditions were investigated. An online analytical method for detection of estrogens was developed and presented low limits of detection (0.005-0.030 µg/L), wide linear ranges (0.017-20, 0.033-20, and 0.099-20 µg/L), good linearity (r>0.9990), and satisfactory repeatability (relative standard deviation<2.7%). The method was successfully applied to detect trace estrogens in real water samples (bottled pure water and bottled mineral water), satisfactory recoveries were ranged from 80 to 125% with two spiking levels of 2 and 6µg/L.

Spiral stir bar sorptive extraction with polyaniline-polydimethylsiloxane sol-gel packings for the analysis of trace estrogens in environmental water and animal-derived food samples.

A spiral stir bar was proposed by using stainless steel spring as the extraction phase carrier to avoid the extraction phase friction and increase the amount of extraction phase for improving extraction efficiency. The extraction phase is filled in the cavity of the spring, resulting in a larger amount of the extraction phase than that conventionally coated on glass stir bar or stainless steel wire. Polyaniline-polydimethylsiloxane sol-gel packed spiral stir bar was prepared and evaluated for the extraction of five estrogens. The prepared spiral stir bar presented good extraction efficiency/preparation reproducibility and long lifetime (more than 150 reused times) for target estrogens. Based on it, a method of spiral stir bar sorptive extraction combined with high performance liquid chromatography coupled with ultra-violet detection was developed for the analysis of trace estrogens in environmental and food samples. The detection limit for five estrogens was 0.11-.31 µg/L, with the enrichment factors of 83.0-118-fold (maximal enrichment factor: 200-fold). The reproducibility evaluated with each estrogen of 5 µg/L (n=5) was 5.8-8.9%. The method was successfully applied for the determination of estrogens in environmental water and animal-derived food samples.

An ionic-liquid-modified melamine-formaldehyde aerogel for in-tube solid-phase microextraction of estrogens followed by high performance liquid chromatography with diode array detection.

A combination between an ionic liquid and melamine-formaldehyde aerogel on the carbon fibers was developed for in-tube solid-phase microextraction of estrogens with high efficiency. The sorbent has a high enrichment capability for several estrogens. Scanning electron microscopy showed that the aerogel on the carbon fibers has a porous three-dimensional network structure. Several important parameters such as sampling volume, sampling rate, the concentration of organic solvent in sample, pH value of sample as well as desorption time were optimized towards estrogen targets. Comparing with melamine-formaldehyde aerogel coating, the coating gave higher extraction efficiency. Comparing with melamine-formaldehyde aerogel coating, the new coating displays higher extraction efficiency. An online analytical method of estrogens was established, by the combination between in-tube solid-phase microextraction and high performance liquid chromatography with diode array detector. Analytical figures of merit include low limits of detection (<0.20μgL-1), wide linearity (0.15-20μgL-1), high enrichment factors (1028-1256), good extraction repeatability (RSDs<2.5%) and satisfactory preparation repeatability (RSDs<10.5%). The method was applied to the determination of trace estrogen targets in plastic bottle, tap water and surface water. Graphical abstractSchematic representation of online combination between in-tube solid-phase microextraction and high performance liquid chromatography, based on an ionic liquid (IL)-modified melamine-formaldehyde (MF) aerogel coating on carbon fibers (CFs) in a polyether-etherketone (PEEK) tube.

Trace analysis of estrogens in milk samples by molecularly imprinted solid phase extraction with genistein as a dummy template molecule and high-performance liquid chromatography–tandem mass spectrometry

Dummy molecularly imprinted polymer microspheres (DMIPMS) towards estrogens were synthesized by Pickering emulsion polymerization employing genistein (GEN) as a dummy template molecule. The FTIR analysis indicated the successful preparation of the imprinted polymers, and the characterization results of scanning electron microscopy and nitrogen adsorption desorption measurement indicated that the obtained DMIPMS are in possess of regular spherical shapes, porous structures and narrow diameter distribution, a BET surface area of 402.74 m2 g−1, a total pore volume of 0.568 cm3 g−1 and a pore diameter of 3.62 nm. The binding capacity and selectivity of DMIPMS were investigated in equilibrium binding experiments and chromatographic evaluation experiments through scatchard analysis and molecular imprinting factor (IF) analysis, respectively. The MIPs showed high binding capacity and excellent selectivity towards seven selected natural and synthetic estrogens, which are Estrone (E1), 17β-estradiol (βE2), estriol (E3), ethinylestradiol (EE2), dienestrol(DS), diethylstilbestrol (DES), and hexestrol (HEX). A method for selective determination of seven estrogens in milk samples via dummy molecularly imprinted solid phase extraction coupled with HPLC-MS/MS was developed, which showed good linearity from 2 to 500 µg L−1 with a correlation coefficient (R2) of more than 0.999. The detection limits were within the range of 0.10–0.35 µg L−1 and the recoveries of the seven estrogens at three spiking levels (10,100,250 µg L−1) ranged from 88.9% to 102.3% with relative standard deviation (RSD, n = 5) for intra-day and inter-day assays varied from 0.8% to 4.5%. The developed method is thus proven to be efficient and reliable for regular monitoring of trace estrogens in complex matrices such as milk samples.

Development of an effervescent reaction-enhanced microextraction method for preconcentration/extraction of trace estrogens in milk using a reduced graphene oxide-assisted ionic liquid-based nanofluid

Herein, we developed a novel effervescent reaction-enhanced microextraction method for preconcentration/extraction of trace estrogens in milk samples.

Efficient removal of several estrogens in water by Fe-hydrochar composite and related interactive effect mechanism of H2O2 and iron with persistent free radicals from hydrochar of pinewood

Recently, hydrochar (HC) with existed persistent free radicals (PFRs) has attracted researches' attention for the potential application in heterogeneous Fenton-like reactions, but studies on the interactive effects of H2O2, iron, and HC in removal of organic pollutants are still limited. In this paper, magnetic iron (hydr)oxides immobilized hydrochar composite (Fe/HC) derived from hydrothermal carbon (HTC) of pinewood were synthesized and characterized. The interactive effects of H2O2, iron, and HC in the removal of several estrogens were systematically investigated to understand the removal performance and related mechanism, especially at a pH range close to natural water environment. Batch experiments results showed that estrogens could be efficiently removed over Fe/HC material under a wide pH range of 4–9. Based on the analysis of electron spin resonance, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, and electrochemical impedance spectroscopy, mechanism study indicated that the carbon-centered PFRs on the surface of hydrochar can act as electron donors, and transfer the electrons on adsorbed O2 to generate O2− rapidly, while the addition of H2O2 enhanced the transmission ability of electron to produce OH(ads) on the material surface. The iron and hydrochar components contributed to the desirable removal of estrogens via the synergistic effect between catalysis and adsorption. This study provides a promising application for the use of Fe/HC materials on remediation of pollution with trace estrogens in water environment.

Adsorption of Trace Estrogens in Ultrapure and Wastewater Treatment Plant Effluent by Magnetic Graphene Oxide.

In the current study, graphene oxide, Fe3+, and Fe2+ were used for the synthesis of magnetic graphene oxide (MGO) by an in situ chemical coprecipitation method. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were used to characterize the well-prepared MGO. The prepared MGO was used as an adsorbent to remove five typical estrogens (estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (17α-E2), estriol (E3), and synthetic estrogen (EE2)) at the ppb level from spiked ultrapure water and wastewater treatment plant effluent. The results indicated that the MGO can efficiently remove estrogens from both spiked ultrapure water and wastewater treatment plant effluent in 30 min at wide pH ranges from 3 to 11. The temperature could significantly affect removal performance. A removal efficiency of more than 90% was obtained at 35 °C in just 5 min, but at least 60 min was needed to get the same removal efficiency at 5 °C. In addition, an average of almost 80% of the estrogens can still be removed after 5 cycles of MGO regeneration but less than 40% can be reached after 10 cycles. These results indicate that MGO has potential for practical applications to remove lower levels of estrogens from real water matrixes and merits further evaluation.

Facile synthesis of magnetic covalent organic framework nanobeads and application to magnetic solid-phase extraction of trace estrogens from human urine

A rapid and facile approach was developed for the synthesis of core-shell structured magnetic covalent organic framework nanobeads by using the monodisperse Fe3O4 nanoparticles (NPs) as magnetic core, and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks (denoted as Fe3O4@TbBd), which were explored as an adsorbent for magnetic solid-phase extraction (MSPE) of estrogens from human urine sample. The core-shell structured Fe3O4@TbBd nanobeads showed some attractive features involving high specific surface area (202.18 m2/g), uniform pore size distribution (2.8 nm), high magnetic responsivity (41.4 emu/g), as well as excellent thermal and chemical stability, which made it an ideal adsorbent for selective isolation and enrichment of estrogens. Some parameters influencing extraction efficiency, including adsorbent dosage, extraction time, pH, ion strength, desorption solvent and desorption time were investigated systematically. Combined with HPLC–MS, a simple, fast, and sensitive method was developed for the enrichment and sensitive determination of seven estrogens, which showed good linearity (r > 0.9978) in the range of 0.005–10 μg/L, low limits of detection (0.2–7.7 ng/L, S/N = 3), low limits of quantification (0.6–25.6 ng/L, S/N = 10), high enrichment factors (75–197 fold), and good precision with relative standard deviations (RSD) lower than 4.8% for intra-day and 6.7% for inter-day. The proposed method was successfully applied to the analysis of trace estrogens in urine sample of pregnant woman with good recoveries (80.6–111.6%), demonstrating the promising potential of the Fe3O4@TbBd nanobeads as adsorbent in sample pretreatment.

Polymeric ionic liquid-based portable tip microextraction device for on-site sample preparation of water samples

On-site sample preparation is highly desired because it avoids the transportation of large-volume samples and ensures the accuracy of the analytical results. In this work, a portable prototype of tip microextraction device (TMD) was designed and developed for on-site sample pretreatment. The assembly procedure of TMD is quite simple. Firstly, polymeric ionic liquid (PIL)-based adsorbent was in-situ prepared in a pipette tip. After that, the tip was connected with a syringe which was driven by a bidirectional motor. The flow rates in adsorption and desorption steps were controlled accurately by the motor. To evaluate the practicability of the developed device, the TMD was used to on-site sample preparation of waters and combined with high-performance liquid chromatography with diode array detection to measure trace estrogens in water samples. Under the most favorable conditions, the limits of detection (LODs, S/N = 3) for the target analytes were in the range of 4.9–22 ng/L, with good coefficients of determination. Confirmatory study well evidences that the extraction performance of TMD is comparable to that of the traditional laboratory solid-phase extraction process, but the proposed TMD is more simple and convenient. At the same time, the TMD avoids complicated sampling and transferring steps of large-volume water samples.

Simultaneous determination of six estrogens in dairy products by high performance liquid chromatography-triple quadrupole-ion trap mass spectrometry coupled with matrix solid-phase dispersion and solid phase extraction

Matrix solid-phase dispersion (MSPD) and solid-phase extraction (SPE) were respectively developed for the pretreatment six estrogens in milk powder and liquid milk. It was implied that MSPD was suitable for the treatment of milk powder, while SPE was suitable for liquid milk treatment. Based on the optimized pretreatment procedures, the method for the simultaneous determination of the six estrogens in different dairy products was established by high performance liquid chromatography-triple quadrupole-ion trap mass spectrometry (HPLC-Q-TRAP-MS). The proposed method provided low limits of detection (LODs, 0.01-0.05 mg/L) and limits of quantification (LOQs, 0.05-0.10 mg/L), wide linearity range of 0.1-200 mg/L (except for estriol of 0.1-20 mg/L) with excellent correlation coefficients (R2)> 0.99. The average recoveries of the six estrogens in milk powder pretreated by MSPD ranged from 71.8% to 106.0% with RSD of 1.6%-9.2% (n=3), while the corresponding average recoveries in liquid milk pretreated by SPE ranged from 70.3% to 108.4% with RSD of 2.0% and 11.0% (n=3) with spiking levels of 1.0, 5.0, and 10 mg/kg, respectively. This sensitive and reliable method meets the demand for the analysis of trace estrogen residues in complex matrices.