Preparation of magnetic molecularly imprinted polymers for the rapid and selective separation and enrichment of perfluorooctane sulfonate

As a persistent organic pollutant, perfluorooctane sulfonate has drawn a great worldwide attention. In this contribution, a novel material of magnetic molecularly imprinted polymers, based on perfluorooctane sulfonate, as a template, molecule was prepared. The magnetic molecularly imprinted polymers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and vibrating sample magnetometry. The adsorption isotherm was measured, and adsorption kinetic tests were conducted. The adsorbents possess high recognition ability (2.460 mg/g) and short adsorption equilibration time (60 min). Besides, they show good specificity and good reusability with the adsorption capacities of adsorbent toward perfluorooctane sulfonate decreasing less than 3% after five adsorption–desorption cycles. The magnetic molecularly imprinted polymers were used successfully in the separation and enrichment of perfluorooctane sulfonate in real water sample and exhibited good prospects in environmental treatment and monitoring.     

盐酸奎宁与全氟辛烷磺酸体系的共振光散射光谱研究及其分析应用

研究了盐酸奎宁(Quinine dihydrochloride,简称Quinine)与全氟辛烷磺酸(perfluorooctane sulfonate,简称PFOS)相互作用的共振光散射(resonance light scattering,RLS)光谱,并建立了PFOS的共振光散射分析方法.在pH值为2.87的Britton-Robinson(BR)缓冲溶液中,全氟辛烷磺酸根阴离子与质子化的盐酸奎宁通过静电引力和疏水作用形成2:1的离子缔合物,引起共振光散射强度(IRLS)显著增强,最大散射波长位于283nm处,增强的散射信号强度与PFOS浓度在0.10～50.0μmol/L范围内呈线性关系,据此建立了测定PFOS的散射分析方法,检测限为9.88nmol/L.讨论了体系的最佳反应条件及外来物质的干扰,同时研究了体系的吸收光谱及荧光光谱,并探讨了反应机理.本方法用于水样及人体血清样品中PFOS的测定,RSD≤4.2%.     

全氟辛烷磺酸与蛋白质体系的共振光散射光谱及其分析应用

研究了牛血清白蛋白(BSA)与全氟辛烷磺酸(PFOS)相互作用的共振光散射(RLS)光谱,建立了PFOS的共振光散射分析方法。 在pH值为4.1的BR缓冲溶液中,全氟辛烷磺酸根阴离子与质子化的BSA通过静电引力和疏水作用形成离子缔合物,引起共振光散射强度(IRLS)显著增强,最大散射波长位于285.0 nm处,增强的散射信号强度与PFOS浓度在0.2～25.0 μmol/L范围内呈线性关系,据此建立了测定PFOS的光散射分析方法,检出限为20.0 nmol/L。 讨论了体系的最佳反应条件及外来物质的干扰,并探讨了反应机理。 建立的共振光散射法用于环境水样中PFOS的测定,RSD≤4.4%。     

Ultraviolet irradiation-induced substitution of fluorine with hydroxyl radical for mass spectrometric analysis of perfluorooctane sulfonyl fluoride

A rapid and solvent free substitution reaction of a fluorine atom in perfluorooctane sulfonyl fluoride (PFOSF) with a hydroxyl radical is reported. Under irradiation of ultraviolet laser on semiconductor nanoparticles or metal surfaces, hydroxyl radicals can be generated through hole oxidization. Among all fluorine atoms of PFOSF, highly active hydroxyl radicals specifically substitute the fluorine of sulfonyl fluoride functional group. Resultant perfluorooctane sulfonic acid is further ionized through capture of photo-generated electrons that switch the neutral molecules to negatively charged odd electron hypervalent ions. The unpaired electron subsequently initiates α O-H bond cleavage and produces perfluorooctane sulfonate negative ions. Hydroxyl radical substitution and molecular dissociation of PFOSF have been confirmed by masses with high accuracy and resolution. It has been applied to direct mass spectrometric imaging of PFOSF adsorbed on surfaces of plant leaves.     

应用于全氟辛烷磺酸萃取富集的全氟癸基修饰毛细管硅胶整体柱的制备及应用

利用溶胶-凝胶法,经过烷氧基硅烷的水解、硅羟基的缩聚、凝胶化、陈化、中孔制备、干燥和表面修饰等步骤制备了全氟癸基修饰的毛细管硅胶整体柱。采用该整体柱对全氟辛烷磺酸(PFOS)进行萃取富集,考察其富集特性和效率,并与传统的C18毛细管硅胶整体柱进行对比。结果表明,全氟癸基修饰毛细管硅胶整体柱(15 cm×75μm)对PFOS具有更高的吸附量和更好的富集选择性,其平均吸附量可以达到75 ng;样品中PFOS的质量浓度为0.25 mg/L时,富集倍数平均可以达到29倍。此全氟癸基修饰毛细管硅胶整体柱对PFOS具有良好的萃取富集性能,可用于水质中痕量PFOS的萃取富集。     

A fast and simple procedure for determination of perfluoroalkyl substances in food and feed: a method verification by an interlaboratory study

In this study, a simple, fast, and cheap sample preparation procedure for the analysis of three well-known representatives of perfluoroalkyl substances (perfluorooctane sulfonate, perfluorooctanoic acid, and perfluorooctane sulfonamide) was validated in accordance with Commission Decision 2002/657/EC. The method was based on extraction with methanol followed by a dispersive solid phase extraction cleanup step by addition of activated charcoal for fish tissue, fish feed, and milk samples. The novel analytical approach combined with liquid chromatography–tandem mass spectrometry makes it possible to achieve limits of quantification below 1 μg/kg (defined by Commission Recommendation 2010/161/EU). This method provides a high laboratory sample throughput: ten samples in 60 min. The validated procedure was successfully verified in an interlaboratory study.     

The study of interaction between PFOA/PFOS and uracil by topology quality and spectroscopic analysis

It has been established that perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) can be considered as emerging persistent organic pollutants. In recent years, there was increasing distribution of PFOA/PFOS in environmental systems, and accumulation and toxic effects of PFOA/PFOS in human body. In this paper, quantum chemistry methods were employed to study the interaction between perfluorinated organic pollutants and base (uracil). The results showed that there were four stable binding modes between the two perfluorinated compounds with uracil, especially the second mode which caused the most detrimental physiological functional response. NBO analysis showed that reactive hydrogen in the two perfluorinated compounds had the greatest effect on the hydrogen bond. The nature of the hydrogen bond formed between the two perfluorinated compounds and base was investigated using the AIM theory. The changes of spectroscopic properties in complexes were analyzed by IR and NMR spectra.     

全氟辛烷磺酰基化合物(PFOS)的污染现状与研究趋势

全氟辛烷磺酰基化合物（PFOS,perfluorooctane sulfonate）所造成的污染已经逐渐成为全球性环境问题,发达国家非常重视PFOS等全氟化合物的研究,已经成为持久性有机污染物研究的又一个热点。本文对目前PFOS研究的现状、进展,以及存在的问题做了简要回顾,并且对今后研究重点做了预测,希望对PFOS研究者提供参考。     

Evaluation of perfluorinated compounds in seven wastewater treatment plants in Beijing urban areas

The presence of perfluorinated compounds(PFCs)in seven major wastewater treatment plants(WWTPs)in Beijing was investigated in the current study.We detected nine PFCs in all the wastewater and sludge samples.Perfluorooctane acid(PFOA)is the dominant PFCs in influents and effluents,while perfluorooctane sulfonate(PFOS)is the major contaminant in sludge.The highest PFC concentration was found in plants at Qinghe and Jiuxianqiao WWTP,while the lowest was found at Fangzhuang WWTP.The total values of PFC range fr...     

Certified calibration solution reference material for the determination of perfluorooctane sulfonate from the National Metrology Institute of Japan (NMIJ)

A new calibration solution reference material for the determination of perfluorooctane sulfonate anion (PFOS) and its salts has been issued as a certified reference material (CRM) by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). The purity amount-of-substance fraction of raw material potassium perfluorooctane sulfonate (K-PFOS) was evaluated based on the results obtained using the freezing point depression method, and the purity mass fraction of the raw material was calculated using the average molar mass of impurities, the molar mass of K-PFOS, and the purity amount-of-substance fraction. The certified concentration of this CRM was obtained by multiplying the dilution ratio of the raw material in a prepared solution (methanol) determined from the gravimetric blending method by the purity of the raw material. The preparation concentration of K-PFOS as a certified value of NMIJ CRM 4220-a was determined to be 9.93?mg?kg^?1. In addition, the standard uncertainty of the certified value was evaluated from the purity evaluation as well as from sample inhomogeneity, instability, and preparation variation obtained from LC/MS measurements of different gravimetrically prepared solutions of the NMIJ CRM. Consequently, the expanded uncertainty was estimated to be 0.15?mg?kg^?1 with a coverage factor k?=?2 corresponding to the half-width of estimated confidence interval of approximately 95%.     

羟基磺基甜菜碱氟碳表面活性剂在油水界面的扩张粘弹性

氟碳表面活性剂是目前表面活性最高的特种表面活性剂,在三次采油等领域具有良好的应用前景。 用小幅周期振荡法研究了羟基磺基甜菜碱型氟碳表面活性剂(FS)在油-水界面的扩张粘弹性能,考察了振荡频率、FS质量分数、无机盐(NaCl、CaCl₂、MgCl₂)对FS在油-水界面的扩张粘弹性能的影响。 结果表明,FS溶液在油水界面的扩张模量、扩张弹性和扩张粘度随着FS质量分数的增加而出现最大值,随着频率的增大而略有增加。 加入无机盐时,扩张模量、扩张弹性随NaCl质量分数增大而出现最大值,而随着CaCl₂或者MgCl₂质量分数的增加,FS溶液的扩张模量、扩张弹性和扩张粘度减小,而当CaCl₂或者MgCl₂质量分数分别为0.05%、0.1%时,tanθ达到最大值。     

Detection of Per- and Polyfluoroalkyl Substances (PFAS) by Interrupted Energy Transfer

The ubiquitous presence of per- and polyfluoroalkyl substances (PFAS) in aqueous environments has aroused societal concern. Nonetheless, effective sensing technologies for continuous monitoring of PFAS within water distribution infrastructures currently do not exist. Herein, we describe a ratiometric sensing approach to selectively detect aqueous perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at concentrations of μg ⋅ L⁻¹. Our method relies on the excitonic transport in a highly fluorinated poly(p-phenylene ethynylene) to amplify a ratiometric emission signal modulated by an embedded fluorinated squaraine dye. The electronic coupling between the polymer and dye occurs through overlap of π-orbitals and is designed such that energy transfer is dominated by an electron-exchange (Dexter) mechanism. Exposure to aqueous solutions of PFAS perturbs the orbital interactions between the squaraine dye and the polymer backbone, thereby diminishing the efficiency of the energy transfer and producing a “polymer-ON/dye-OFF” response. These polymer/dye combinations were evaluated in spin-coated films and polymer nanoparticles and were able to selectively detect PFAS at concentrations of ca. 150 ppb and ca. 50 ppb, respectively. Both polymer films and nanoparticles are not affected by the type of water, and similar responses to PFAS were found in milliQ and well water.     

混合无机酸消解-固相萃取-高效液相色谱-串联质谱法分析贝类壳体中的3种全氟磺酸化合物

建立了采用混合无机酸消解-固相萃取(SPE)-高效液相色谱-电喷雾电离串联质谱(HPLC-ESI-MS/MS)分析贝类壳体中的3种全氟磺酸化合物的方法。将贝壳粉经硝酸/盐酸混合酸消解,用氢氧化钠调节消解液的pH值至6后采用Oasis WAX固相萃取柱富集净化,然后采用内标法通过HPLC-ESI-MS/MS在分时段选择反应监测模式下分析上述全氟磺酸化合物。结果表明,该方法对于贝壳中全氟丁烷磺酸、全氟己烷磺酸和全氟辛烷磺酸的检出限(LOD)分别为0.28, 0.42和0.43 ng/g,加标回收率为94.88%～96.24%。采用此方法对渤海湾两种双壳贝类壳体进行的采样分析也表明,贝壳中3种目标污染物的含量范围为＜LOD～0.70 ng/g,比其在贝类软组织中的含量低约1个数量级。实验结果表明混合酸消解-SPE提取是检测贝类壳体中此类污染物的有效前处理方法。     

Conductive,Stretchable,and Self-healing Ionic Gel Based on Dynamic Covalent Bonds and Electrostatic Interaction

Integrating multiple functions into one gel that can be widely applied to electronic devices as well as chemical and biomedical engineering remains a big challenge.Here,a multifunctional ionic liquid/dynamic covalent bonds (ionic/DCB) type gel was designed and synthesized via one-pot polymerization.With the assistance of electrostatic interaction provided by the imidazolium cations of IL and the reversible DCB of boronic ester,as-prepared ionic/DCB gel showed good stretchable properties and high ionic conductivity at ambient conditions.In addition,the electrostatic interaction between imidazolium cations and sulfonate anions and the reversible DCB led to enhanced chain mobility and thereby excellent self-healing properties.Particularly,sulfonate anions in ionic/DCB gel could alleviate the migration of electronegative polysulfide and promote the transportation of electropositive lithium ion in lithium-sulfur battery system.Therefore,this work provides a new insight to promote the current research on self-healing gels,hopefully expanding their applications in electronic devices.     

Solute-solvent interactions in micellar electrokinetic chromatography: IV. Characterization of electroosmotic flow and micellar markers

A wide study of the compounds and procedures mostly used to determine the electroosmotic flow (EOF) and micelle elution times has been done in seven different micellar electrokinetic chromatography (MEKC) systems. These systems are formed from mixtures of an aqueous buffer with the surfactants sodium dodecyl sulfate, lithium dodecyl sulfate, lithium perfluorooctane sulfonate, sodium cholate, sodium deoxycholate, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide. The solvation parameter model has been used to evaluate the usefulness of the compounds studied as EOF or micellar markers in each of the seven MEKC systems. It is demonstrated that methanol, acetonitrile and formamide are the best EOF markers, and that dodecanophenone is the best micellar marker.     

Organic–inorganic hybrid fluorous monolithic capillary column for selective solid‐phase microextraction of perfluorinated persistent organic pollutants

A novel construction strategy of monolithic capillary column for selectively enriching perfluorinated persistent organic pollutants was proposed. The organic–inorganic hybrid fluorous monolithic capillary column was synthesized by a “one‐pot” approach via the polycondensation of γ‐methacryloxypropyltrimethoxy‐silane, then in situ copolymerization of 1H,1H,7H‐dodecafluoroheptyl methacrylate and vinyl group on the precondensed siloxanes. The obtained monolithic columns were systematically characterized. The results demonstrated that the optimal column possessed good mechanical stability and high permeability. The adsorption capacities of the optimized monolithic column for perfluorooctanoic acid and perfluorooctane sulfonate were 0.257 and 0.513 μg/mg, respectively. Adsorption capacities of the monoliths were proved to increasing with increasing the amounts of fluorinated monomers in the fluorous monoliths. Sodium 1‐octanesulfonate, as a comparison compound, was hardly adsorbed on the fluorous monolith. In addition, the trace amounts of perfluorooctanoic acid and perfluorooctane sulfonate in water samples can be successfully concentrated about 160 times to their original concentrations by this monolithic column. These results demonstrated that the capacity and selectivity of the affinity fluorous column is high and can be applied to the selective enrichment for the perfluorinated persistent organic pollutants from environmental samples.     

Fluorescence detection of perfluorooctane sulfonate in water employing a tetraphenylethylene-derived dual macrocycle BowtieCyclophane

Because the widely used perfluorooctane sulfonate(PFOS) is harmful to both environment and human health, it is of great significance and urgency to develop sensitive and selective sensors for the detection of trace PFOS in water. In this study, a tetraphenylethylene-derived macrocycle Bowtie Cyclophane has been developed as a fluorescent sensor based on aggregation-induced emission enhancement and fluorochromism. Sensitive detection of PFOS has been achieved with a limit of detection(LOD) of47.3...     

Modified polyaniline through simultaneous electrochemical polymerization of aniline and metanilic acid

Simultaneous electropolymerization of aniline and metanilic acid in aqueous HClO₄ leads to a copolymer similar to that obtained by direct sulfonation of polyaniline. Characterization by electrochemical and spectroscopic methods (UV -visible, Fourier transform IR and proton NMR) indicated the presence of polyaniline linear chains in which metanilic acid units were inserted as spacers. Elemental analysis showed that the copolymer was 40% doped by the sulfonate side-groups intramolecularly (self-doping) and 20% doped by ClO₄⁻ intermolecularly. The presence of sulfonate functional groups decreased electronic conductivity and increased solubility in alkaline solvents, but the electtrochemical properties remained principally that of polyaniline.     

HPLC-MS/MS与ICP-MS分别测定血液中14种全氟化合物及常见金属元素

为了解广东儿童血液中全氟化合物(PFCs)和常见金属元素的含量水平,为儿童健康评估提供数据,该文采用蛋白沉淀法提取样品,高效液相色谱-串联质谱(HPLC-MS/MS)检测样品中14种PFCs。同时,以石墨全自动消解仪消解血液样品,电感耦合等离子体质谱(ICP-MS)检测血液中钙(Ca)、镁(Mg)、铁(Fe)、锌(Zn)、铜(Cu)和锰(Mn)元素。结果显示,儿童血液中14种PFCs被普遍检出,其中全氟辛基磺酸(PFOS)和全氟辛基羧酸(PFOA)的检出率及浓度最高,但在一些个体中发现较高浓度的其它碳链PFCs。PFCs浓度有随着年龄增长而下降的趋势,但除了全氟丁基磺酸外,无性别差异。另一方面,儿童血液中检出的Ca、Mg、Fe、Zn、Cu和Mn含量在正常范围内,未发现有性别差异。研究显示PFCs普遍存在儿童血液中,儿童PFCs暴露水平的研究应引起重视。在今后的监测中,不仅要关注PFOS和PFOA,也要关注其它碳链PFCs。     

Use of high-resolution mass spectrometry to identify precursors and biodegradation products of perfluorinated and polyfluorinated compounds in end-user products

Structural identification of perfluoroalkyl and polyfluoroalkyl substances found in end-user products and their biodegradation products was performed using ultra-high resolution mass spectrometry. Little attention has so far been paid to the environmental burden of perfluorooctane sulfonate and perfluorooctanoic acid from compounds with a molar mass of ~2,000. Analysis of end-user waterproofing and stain repellent products revealed the presence of numerous ions with molar masses ranging from 1,000 to 2,000 and complex mass spectra. Ultra-high resolution mass spectrometry determined the accurate mass of the observed ions, allowing the cleavage position and fragment structure to be determined. The precursor structures were determined based on reconstitution of the retrieved fragments. Products of fluorochemical manufacturers before voluntary regulation comprised compounds with plural perfluorooctyl chains. In the current product lines, compounds comprising perfluorobutyl chains were detected. Biodegradation tests using activated sludge revealed that biodegradation products consistent with those reported previously were generated even from complex end-user products. For example, the biodegradation test revealed the formation of N-ethyl perfluorooctane sulfonamido acetic acid and various fluorotelomer acids in the samples. The results of the present study suggest that the environmental burden of these compounds should be reevaluated.