离子液体键合固相微萃取涂层用于水样中五氯酚的测定

合成了1-甲基-3-三乙氧基硅基丙基咪唑二(三氟甲基磺酸酰)亚胺盐([TPMIM][NTf2])离子液体, 其热稳定性可达480 ℃, 并用其通过溶胶-凝胶法制备了一种含键合离子液体的固相微萃取(SPME)涂层. 该涂层的使用温度可达340 ℃. 优化了萃取温度、萃取时间、溶液的pH、盐效应、解析温度以及解析时间. 在最优条件下, 采用顶空固相微萃取结合GC/FID的方法测定水样中五氯酚(PCP)的检出限为1 ng/L, 线性范围为10-3~102 μg/L, 线性相关系数为0.9994, 相对标准偏差(RSD, n=5)为3.5%, 加标回收率为84.5%.     

Fe_3O_4@SiO_2-NH_2磁性复合材料对水中全氟化合物的检测研究

利用三步法(热溶剂还原法,硅烷化和氨基功能化)制备了Fe3O4@SiO2-NH2磁性纳米复合材料用于水体中全氟化合物的萃取,结合超高效液相色谱-串联三重四极杆质谱(UPLC-MS/MS)技术,建立了水体中7种典型全氟化合物的检测方法。通过扫描电镜(SEM)、透射电镜(TEM)和傅立叶红外光谱(FT-IR)等手段对材料进行表征,详细研究了解析溶剂、解析溶剂体积、解析时间、吸附时间和p H值等因素对萃取效率的影响。结果表明:氨基被成功修饰在Fe3O4@SiO2纳米粒子的表面,Fe3O4@SiO2-NH2磁性纳米材料对目标全氟化合物有较好的萃取效果,在萃取时间为20 min,解析溶剂为3 m L×4含0.28%氨水的甲醇,解析时间为5 min,p H 5.0时,萃取效率最佳。在最优实验条件下,全氟化合物的检出限为0.2~0.5 ng/L,线性范围为1~500 ng/L。方法用于实际水体中目标全氟化合物的检测,样品的加标回收率不低于82.0%。     

基于水滑石-金纳米粒子的阻抗型核酸适配体传感器的研究

在玻碳电极表面用电化学沉积法一步合成钴铝水滑石-金纳米粒子(CoAl LDH-GNPs)复合纳米材料,以复合纳米材料作为核酸适配体(Apt)的固定化基质,建立了一种高灵敏的阻抗型适配体传感器.采用扫描电镜(SEM)和能量色散谱仪(EDS)对CoAl LDH-GNPs复合纳米材料进行了表征,对电极的组装过程采用循环伏安法和电化学阻抗进行表征,对传感器的性能采用电化学阻抗进行研究.复合纳米材料CoAl LDH-GNPs构筑的传感器对凝血酶(THR)具有良好的信号响应,线性相关系数R=0.995,检出限为0.3 ng/L(S/N=3),检测范围为1.0 ng/L～ 100 μg/L.     

羧基化单壁碳纳米管涂层同时测定纯净水中的烷基酚和双酚A

用溶胶-凝胶方法制备了羧基化碳纳米管溶胶凝胶固相微萃取涂层,采用顶空固相微萃取-气相色谱法测定纯净水中的烷基酚和双酚A.优化了萃取涂层的萃取时间、萃取温度、盐浓度以及解析时间等实验参数.结果表明,在萃取温度为90℃和盐浓度为0.36 g/mL的条件下萃取30 min,250℃下解析3 min,涂层的萃取效果最好.与商用...     

磁性氮掺杂石墨烯固相萃取环境水样中的4种有机氯污染物

采用化学共沉淀法成功合成了磁性氮掺杂石墨烯纳米材料, 对其吸附性能进行了初步探讨.此磁性纳米材料对对氯间二甲苯酚的吸附不局限于均匀的单分子层吸附,吸附动力学符合准二级动力学模型.将其作为磁性固相吸附剂,通过对吸附剂用量、超声萃取时间、水样pH值、上样体积等条件的优化,建立了超声辅助磁性固相萃取-气相色谱/串联质谱同时测定环境水样中的三氯生(TCS)、对氯间二甲苯酚(PCMX)、六氯苯(HCB)和2,2′,4,4′,5,5′-六氯联苯(PCB-153) 4种有机氯污染物的方法. 在优化条件下,将6.0 mg Fe3O4/N-G分散于100 mL水样中,调节水样至pH 5,超声萃取15 s,磁性分离,3 mL乙醇和2 mL二氯甲烷分步洗脱,洗脱液氮吹定容,进行气相色谱-质谱联用分析.4种有机污染物在0.1~10 μg/L范围内与峰面积呈良好的线性关系,相关系数为0.9983~0.9999,检出限(S/N=3)和定量限(S/N=10)分别为0.05~0.6 ng/L和0.4~2.4 ng/L,3个加标浓度水平的回收率为68.3%~103.4%,日内、日间测定的相对标准偏差分别为3.3%~6.9%和3.4%~9.4%(n=6).本方法简单方便,易于操作,适用于环境水样中有机氯污染物的检测.     

顶空固相微萃取/气相色谱-质谱联用测定水中6种挥发性硅氧烷

建立了水中4种环形和2种线形硅氧烷的顶空固相微萃取/气相色谱-质谱联用分析方法.考察了萃取纤维、萃取温度、萃取时间、水样pH值、解析时间、盐效应等因素对实验结果的影响.优化后的条件为:40mL水、40 μL内标(M4Q,500 μg/L)、NaCl(0.1 g/mL)加入60 mL顶空瓶中,选用65μm聚二甲基硅氧烷-二乙烯基苯(PDMS/DVB)纤维于24℃顶空萃取45 min.萃取完成后将纤维插入气相色谱进样口,于200℃解吸2 min进行定性、定量分析.结果表明,6种目标物的方法检出限为(LOD)2.6～7.8 ng/L,回收率为82％～ 96％,相对标准偏差(RSD)为1.1％～7.9％.     

热解析-高场非对称波形离子迁移谱(FAIMS)技术快速检测合成色素

采用热解析-高场非对称波形离子迁移谱(FAIMS)技术快速检测柯衣定、 孔雀石绿、 罗丹明B和甲基红4种合成色素. 通过对热解析温度和载气流量进行优化, 确定了不同色素的离子特征信号. 在最佳分析条件下, 热解析温度为160 ℃, 载气流量为1.6 L/min, 采用不同模式下补偿电压(CV)值定性, 以FAIMS在正模式下检测柯衣定(CV=0.41 V)和罗丹明B(CV=-0.89 V), 在负模式下检测甲基红(CV=-0.67 V)和孔雀石绿(CV=0.02 V); 用外标法定量检测了样品中的4种合成色素, 线性关系R²≥0.9967, 检出限为2.5~10 μg/L, 定量限为5~20 μg/L, 加标回收率≥78.2%, 相对标准偏差RSD≤8%. 本文为FAIMS技术快速检测合成色素提供了一定的技术基础.     

非晶纳米材料用于电解水的研究进展

电催化水分解产氢作为一种有前途的制氢技术被全世界研究者广泛关注.然而,此领域仍然缺少一种高效、无污染的催化剂,以降低能耗,提升反应动力学,进而推进电解水的实际应用.近年来研究发现,具有短程有序、长程无序特征的非晶纳米材料在电解水领域表现出极其优异的性能.有趣的是,固有的无序结构赋予了非晶纳米材料丰富的高活性位点.鉴于此,本文综述了非晶纳米材料的制备策略以及表征方法,并且对其高活性来源进行了系统地分析.此外,本文通过分析近几十年的研究成果指出了非晶纳米材料在电解水领域面临的挑战和应用前景.非晶纳米材料的合成方法主要分为两类:直接合成和间接合成.直接合成主要包括:电沉积、光化学金属-有机沉积、气溶胶-喷雾辅助法、反胶束溶胶-凝胶法、水热法、共沉淀法和氧化还原法.其中,气溶胶-喷雾辅助技术可以通过控制母液中金属离子的浓度精准地控制非晶纳米材料中各种金属元素的组成,从而有目的地调控并优化催化活性.间接合成主要分为原位转化和非原位转化.原位转化是指晶体材料在反应过程中表面会原位转化为非晶结构作为反应的真实活性物质.非原位转化是指当纳米材料尺度非常小时,高表面能将会破坏材料的结晶度得到非晶材料.另外,非晶材料长程无序的特点给其表征带来极大挑战.目前,对于非晶材料表征的一般流程是:首先通过X射线粉末衍射确定非晶结构,并通过透射电子显微镜以及扫描电子显微镜探索其形貌结构;再通过选区电子衍射以及高角度环形暗场扫描透射电子显微镜进一步确定非晶结构;然后,通过能谱、电感耦合等离子体发射光谱和X射线光电子能谱分析其化学组成及化学态;最后,采用拉曼光谱和同步辐射数据提供晶体结构信息.本文对非晶纳米材料高活性的起源进行了探究.在电解水领域,非晶纳米材料通常表现出优于晶体材料的性能.优异的活性与活性位点数量的增多以及活性位点活性的提升有关:(1)非晶纳米材料具有长程无序的特征,可以暴露更多活性位点,并且其表面存在的大量悬挂键也可以作为活性位点;(2)非晶纳米材料的活性位点可以拓展至催化剂体相内部,大幅提升了活性位点数量;(3)非晶纳米材料结构灵活性高,活性位点在催化反应过程中可以转变成任意形状,提升了活性位点的活性;(4)非晶纳米材料的高韧性和应变能力赋予其较高的稳定性.非晶纳米材料已广泛应用于电解水领域,但仍然存在一些问题:(1)非晶纳米材料由于原子级结构不确定,其电催化机理很难探究;(2)理论模拟作为研究电化学反应途径的有力工具很难应用于非晶纳米材料的研究;(3)随着无序程度的增加,活性位点数量和活性逐渐增加,但电导率逐渐下降.尽管如此,由于非晶纳米材料结构灵活性高和自重组能力快速,人们对其在电解水领域的研究兴趣越来越大,并且该领域显示出良好的应用前景,高效非晶纳米材料的设计合成及其催化机理的研究将成为今后研究的重点.     

纳米金-钛酸纳米管复合材料的合成与表征

以氯金酸和钛酸钠米管(NTA)为原料,柠檬酸三钠为稳定剂,硼氢化钠为还原剂,于室温条件下合成了一种金纳米颗粒-钛酸纳米管(GNPs-NTA)复合纳米材料;利用红外光谱仪、透射电镜、X射线粉末衍射仪等分析了产物的化学键合特征、微结构及相组成,并考察了产物对辣根过氧化酶(HRP)结构和生理活性的影响.结果表明,合成的纳米金颗粒粒径(平均5.3nm)分布窄,且均匀分布于钛酸纳米管表面.此外,HRP与GNPs-NTA复合纳米材料充分振荡混合后仍能保持其二级结构不变,有利于保持其生理活性.     

2-乙基己基膦酸单(2-乙基己基)酯对两价金属离子的萃取平衡

本文报导用2-乙基己基膦酸单(2-乙基己基)酯在煤油溶剂中萃取Sn(II),Pb(II), Zn(II)和Cd(II)等的平衡, 应用斜率法研究了萃取平衡; 合成了与Zn(II)和Pb(II)固体萃合物, 在元素分析和有关离子分析的基础上结合最小二乘法线性回归探讨了萃取机理及有关萃合物组成; 考察了在加入三辛基氧化膦(TOPO)时, 2,乙基己基膦酸单(2-乙基己基)酯对金属离子萃取性能的影响.     

Magnetic graphene oxide modified by imidazole‐based ionic liquids for the magnetic‐based solid‐phase extraction of polysaccharides from brown alga

Magnetic graphene oxide was modified by four imidazole‐based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid‐phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field‐emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single‐factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid–liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid‐modified magnetic graphene oxide materials, and amount of 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic‐liquid‐modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties.     

Facile synthesis of a novel magnetic covalent organic frameworks for extraction and determination of five fungicides in Chinese herbal medicines

A novel magnetic covalent organic framework was synthesized via a one-step coating approach with solvothermal reaction employing 2,4,6-tris(4-aminophen-yl)-1,3,5-triazine and 2,4,6-triformylphloroglucinol as two building blocks by covalent bonding. The prepared magnetic covalent organic frameworks were properly characterized by different techniques and employed as adsorbents of magnetic solid-phase extraction. An analytical method was developed for the simultaneous determination of five fungicides in two Chinese herbal medicine samples via magnetic solid-phase extraction coupled to ultra high performance liquid chromatography with tandem mass spectrometry analysis. Under optimized magnetic solid-phase extraction conditions, the method exhibited satisfactory recoveries (74.0−109.6%) with relative standard deviations of 0.4−4.6%, low limits of detection (0.003−0.015 μg/kg), and good linearity (R² > 0.9960). Compared with the traditional extraction method, the proposed method required a lower amount of adsorbent (3 mg) and extraction time (5 min). The adsorbent also had favorable reusability (not less than eight times). Therefore, the magnetic covalent organic frameworks could be a promising adsorbent for the extraction and quantitation of fungicides in Chinese herbal medicines.     

Extraction of ochratoxin A in red wine with dopamine‐coated magnetic multi‐walled carbon nanotubes

A new, rapid, green, and cost‐effective magnetic solid‐phase extraction of ochratoxin A from red wine samples was developed using polydopamine‐coated magnetic multi‐walled carbon nanotubes as the absorbent. The polydopamine‐coated magnetic multi‐walled carbon nanotubes were fabricated with magnetic multi‐walled carbon nanotubes and dopamine by an in situ oxidative self‐polymerization approach. Transmission electron microscopy, dynamic light scattering, X‐ray photoelectron spectroscopy and vibrating sample magnetometry were used to characterize the absorbents. Ochratoxin A was quantified with high‐performance liquid chromatography coupled with fluorescence detection, with excitation and emission wavelengths of 338 and 455 nm, respectively. The conditions affecting the magnetic solid‐phase extraction procedure, such as pH, extraction solution, extraction time, absorbent amount, desorption solution and desorption time were investigated to obtain the optimal extraction conditions. Under the optimized conditions, the extraction recovery was 91.8–104.5% for ochratoxin A. A linear calibration curve was obtained in the range of 0.1–2.0 ng/mL. The limit of detection was 0.07 ng/mL, and the limit of quantitation was 0.21 ng/mL. The recoveries of ochratoxin A for spiked red wine sample ranged from 95.65 to 100.65% with relative standard deviation less than 8%. The polydopamine‐coated magnetic multi‐walled carbon nanotubes showed a high affinity toward ochratoxin A, allowing selective extraction and quantification of ochratoxin A from complex sample matrixes.     

磁性多壁碳纳米管固相萃取-气相色谱-质谱法检测水样中的13种邻苯二甲酸酯类化合物

建立了磁性多壁碳纳米管(MWCNTs)固相萃取结合气相色谱-质谱检测水样中13种邻苯二甲酸酯类化合物(PAEs)的方法。优化了萃取时间、水样pH值、解吸溶剂的种类和用量、解吸时间等影响萃取效率的主要条件。最终确定萃取时间为10 min,水样pH 5～7,解吸溶剂为2 mL丙酮,解吸时间为5 min。在优化的条件下,各组分的萃取回收率为89.7%～100.5%。方法具有较高的灵敏度,检出限(信噪比(S/N)为3)为0.08～0.47 μg/L。3种实际样品的加标回收率为84.5%～107.5%,相对标准偏差为1.9%～12.8%。该方法操作简便、省时,准确、灵敏、环保,可用于水样中PAEs的检测,并成功地应用于自来水、瓶装饮用水和湖水样品的分析,13种PAEs均未检出。     

Preparation of bamboo-derived magnetic biochar for solid-phase microextraction of fentanyls from urine

In this study, a biochar-based magnetic solid-phase microextraction method, coupled with liquid chromatography–mass spectrometry, was developed for analyzing fentanyl analogs from urine sample. Magnetic biochar was fabricated through a one-step pyrolysis carbonization and magnetization process, followed by an alkali treatment. In order to achieve desired extraction efficiency, feed stocks (wood and bamboo) and different pyrolysis temperatures (300–700°C) were optimized. The magnetic bamboo biochar pyrolyzed at 400°C was found to have the greatest potential for extraction of fentanyls, with enrichment factors ranging from 58.9 to 93.7, presumably due to H-bonding and π–π interactions between biochar and fentanyls. Various extraction parameters, such as type and volume of desorption solvent, pH, and extraction time, were optimized, respectively, to achieve the highest extraction efficiency for the target fentanyls. Under optimized conditions, the developed method was found to have detection limits of 3.0–9.4 ng/L, a linear range of 0.05–10 μg/L, good precisions (1.9–9.4% for intrabatch, 2.9–9.9% for interbatch), and satisfactory recoveries (82.0–111.3%). The developed method by using magnetic bamboo biochar as adsorbent exhibited to be an efficient and promising pretreatment procedure and could potentially be applied for drug analysis in biological samples.     

Magnetic solid-phase extraction using Schiff base ligand supported on magnetic nanoparticles as sorbent combined with dispersive liquid-liquid microextraction for the extraction of phenols from water samples

ABSTRACT

In this work, the magnetic sorbent was developed by covalent binding of a Schiff base ligand, N,N’-bis(3-salicyliden aminopropyl)amine (salpr), on the surface of silica coated magnetic nanoparticles (Salpr@SCMNPs). The core-shell nanoparticle was applied for the magnetic solid-phase extraction (MSPE) combined with dispersive liquid-liquid microextraction (DLLME) of phenolic compounds from water samples prior to gas chromatography-flame ionisation detector (GC?FID). Characterisation of the Salpr@SCMNPs was performed with different physicochemical methods such as Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Variables affecting the performance of both extraction steps such as pH of the water sample, the sorbent amount, the desorption conditions, the extraction time; and extraction solvent were studied. Under the optimised conditions, the analytical performances were determined with a linear range of 0.01–100 ng mL^?1 and a limit of detection at 0.003–0.02 ng mL^?1 for all of the analytes studied. The intra-day (n = 5) and inter-day (n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 6.9–8.9% and 7.3–10.1%, respectively. The proposed method was executed for the analysis of real water samples, whereby recoveries in the range of 92.9–99.0% and RSD% lower than 6.1% were attained.     

Preparation of functionalized magnetic nanoparticulate sorbents for rapid extraction of biphenolic pollutants from environmental samples

A new solid-phase extraction coupled with magnetic carrier technology was developed for extraction of bisphenol A (BPA) and diethylstilbestrol (DES) from water samples. The SPE sorbents, functionalized magnetic nanoparticles (Fe₃O₄@SiO₂/β-CD, core/shell), were synthesized in a two-stage system. The material was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and a vibrating sample magnetometer. SPE extraction parameters, such as volume and pH of sample, adsorption time, and desorption conditions were optimized. Under selected conditions: 250 mL of water sample, 0.1 g of sorbents and elution with methanol (3 mL with 1% acetic acid), the extraction was completed in 25 min. SPE followed by HPLC was employed to determine BPA and DES in environmental samples. The developed method provided spiked recoveries of 80–105%, relative standard deviations of less than 7%, and LOD of BPA (20.0 ng/L) and DES (23.0 ng/L), respectively. The proposed method offered easy preparation of sorbents, rapid analysis, high enrichment yields, and reliable quantitative assay.     

A highly sensitive method for detection of bisphenol A in water samples based on functionalised Fe3O4@SiO2@nylon66

A simple and sensitive method was developed for preconcentration and determination of bisphenol A (BPA) in environmental samples by high performance liquid chromatography (HPLC). The hydrophilic silicon-dioxide- and nylon66-functionalised magnetic material (Fe₃O₄@SiO₂@nylon66) was used as a sorbent for magnetic solid-phase extraction (MSPE). With the anhydrous microemulsion reaction, the Fe₃O₄@SiO₂@nylon66 had shown great characteristics such as good magnetic responsivity, water dispersibility and stability. Based on the materials, various extraction parameters including pH, extraction time, elution time, the number of sorbents, sample volume and elution times were optimised. The whole extraction procedure could be accomplished within 20 min and the materials could be used more than 10 times after regeneration. Under the optimised conditions, different types of water samples (Tap water, river water, sea water and underground water) were successfully analysed to verify the applicability of the proposed method. The recoveries of different samples ranged from 88.54% to 104.46%. An enrichment factor of 250 was achieved with 0.05 μg/L detection limit. Thus, the developed MSPE is a potential technique that can be used for water samples preconcentration or combined with other analytical methods for determination of BPA.     

The use of graphene-based magnetic nanoparticles as adsorbent for the extraction of triazole fungicides from environmental water

A graphene-based magnetic nanocomposite (graphene-ferriferrous oxide; G-Fe(3) O(4) ) was synthesized and used as an effective adsorbent for the preconcentration of some triazole fungicides (myclobutanil, tebuconazole, and hexaconazole) in environmental water samples prior to high-performance liquid chromatography-ultraviolet detection. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid the time-consuming experimental procedures commonly involved in the traditional solid phase extraction such as centrifugation and filtrations. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, the pH values of the sample solution, salt concentration, and desorption conditions were investigated. Under the optimum conditions, the enrichment factors of the method for the three analytes were 5824, 3600, and 4761, respectively. A good linearity was observed in the range of 0.1-50 ng/mL for tebuconazole and 0.05-50 ng/mL for myclobutanil and hexaconazole, respectively, with the correlation coefficients ranging from 0.9992 to 0.9996. The limits of detection (S/N = 3) of the method were between 0.005 and 0.01 ng/mL. The results indicated that as a magnetic solid-phase extraction adsorbent, the graphene-ferriferrous oxide (G-Fe(3) O(4) ) has a great potential for the preconcentration of some compounds from liquid samples.     

Extraction of Rutin and Rhoifolin by Inorganic Borate Functionalized Magnetic Particles

We demonstrate a facile approach for smart time‐saving extraction of active components of rutin and rhoifolin by a new kind of magnetic particles (MPs). The inorganic borate functionalized magnetic particles are quasi‐spherical with an average diameter of 200–220 nm. The MPs were characterized by scanning electron microscopy and X‐ray diffraction techniques. The inorganic boron content in MPs was confirmed by electron‐dispersive X‐ray spectroscopy. The extraction and release efficiency of MPs were investigated. The smart borate‐decorated magnetic particles show a specific extraction towards the active components containing cis‐1,2 diol moieties. Rutin and rhoifolin were extracted at 16.55 and 22.49 mg/g, respectively. The recycling test shows that MPs can be reused and maintain a significant efficiency for seven cycles. Hence, a novel structured and reusable magnetic nanomaterial for extracting rutin and rhoifolin was developed. This strategy of specific extraction will be an important method to obtain the active components with some structure features through designing various structured particles.