亲水作用色谱柱与阳离子交换树脂柱结合分离无机离子（英文）

A combination of hydrophilic interaction chromatographic(HILIC) column and a weakly acidic cation-exchange resin(WCX) column was used for simultaneous separation of inorganic anions and cations by ion chromatography(IC).Firstly,the capability of HILIC column for the separation of analyte ions was evaluated under acidic eluent conditions.The columns used were SeQuant ZIC-HILIC(ZIC-HILIC) with a sulfobetaine-zwitterion stationary phase(ZIC-HILIC) and Acclaim HILIC-10 with a diol stationary phase(HILIC-10).When using tartaric acid as the eluent,the HILIC columns indicated strong retentions for anions,based on ion-pair interaction.Especially,HILIC-10 could strongly retain anions compared with ZIC-HILIC.The selectivity for analyte anions of HILIC-10 with 5 mmol/L tartaric acid eluent was in the order of I-> NO-3 > Br-> Cl-> H2PO-4.However,since HILIC-10 could not separate analyte cations,a WCX column(TSKgel Super IC-A/C) was connected after the HILIC column in series.The combination column system of HILIC and WCX columns could successfully separate ten ions(Na+,NH+4,K+,Mg2+,Ca2+,H2PO-4,Cl-,Br-,NO-3 and I-) with elution of 4 mmol/L tartaric acid plus 8 mmol/L 18-crown-6.The relative standard deviations(RSDs) of analyte ions by the system were in the ranges of 0.02%-0.05% in retention times and 0.18%-5.3% in peak areas through three-time successive injections.The limits of detection at signal-to-noise ratio of 3 were 0.24-0.30 μmol/L for the cations and 0.31-1.2 μmol/L for the anions.This system was applied for the simultaneous determination of the cations and the anions in a vegetable juice sample with satisfactory results.     

On-chip type cation-exchange chromatography with ferrocene-labeled anti-hemoglobin antibody and electrochemical detector for determination of hemoglobin A1c level

An on-chip type cation-exchange chromatography system with electrochemical detection of HbA_1c, which is one of the most important diabetes marker protein, was developed using ferrocene-conjugated anti-human hemoglobin (Hb) monoclonal antibody (FcAb). The FcAb was used as an electrochemical probe for the detection of each Hb. The system contains syringe pump, on-chip type cation-exchange column consisted of PDMS and cation-exchange resin beads, and a three-electrode flow-cell system. The separation conditions of HbA_1c in blood calibrator samples from other Hbs, e.g. HbA₀, HbA_1a or HbA_1b, were optimized using the on-chip type system. The electrochemical oxidation current from FcAb reacting with each Hb was measured at 350 mV (vs. Ag/AgCl). Hbs including HbA_1a and HbA_1b, HbA_1c and HbA₀ fractions were eluted in this order. A linear relationship between HbA_1c levels and electrochemical oxidation currents was obtained in the range from 4.0% to 12.6% HbA_1c. All procedure including antigen-antibody reaction was completed in 15 min. Furthermore, a good correlation was obtained between KO500 method (HPLC) and our proposed method. These results indicate that the on-chip type system with electrochemical detection can be applied to a novel POCT device for rapid and precise detection of HbA_1c.     

Hybrid organic–inorganic silica monolith with hydrophobic/strong cation-exchange functional groups as a sorbent for micro-solid phase extraction

A hybrid organic–inorganic silica monolith with hydrophobic and strong cation-exchange functional groups was prepared and used as a sorbent for micro-solid phase extraction (micro-SPE). The hybrid silica monolith functionalized with octyl and thiol groups was conveniently synthesized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), n-octyltriethoxysilane (C8-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) via a two-step catalytic sol–gel process. Due to the favorable chemical reactivity of mercapto pendant moieties, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups, which provided strong cation-exchange sites. The obtained hybrid monolith was characterized by diffused infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The results show that the resulting monolith contains much higher carbon (31.6%) and sulfur (4.8%) contents than traditionally bonded silica materials. The extraction performance of the hybrid monolith was evaluated using sulfonamides as testing analytes by micro-SPE on-line coupled to HPLC. The results show that the hybrid monolith with hydrophobic and strong cation-exchange functional groups exhibits high extraction efficiency towards the testing analytes. The column-to-column RSD values were 1.3–9.8% for the extraction of SAs investigated. The extraction performance of the hybrid silica monolith remained practically unchanged after treated with acid (pH 1.0) and basic solutions (pH 10.5). Finally, the application of the hybrid monolith was demonstrated by micro-SPE of sulfonamide residues from milk followed by HPLC–UV analysis. The limits of detection (S/N = 3) for eight SAs were found to be 1.0–3.0 ng/mL in milk. The recoveries of eight SAs spiked in milk sample ranged from 80.2% to 115.6%, with relative standard deviations less than 11.8%.     

HZSM-5的表面B酸与催化活性

用离子交换法测定了不同温度下焙烧的HZSM-5沸石表面的B酸量;对用离子交换、TPD及IR等方法测定的酸性结果进行了关联;讨论了表面酸性质对乙酸和乙醇的酯化及乙醇分子间缩合反应活性的影响。结果表明,当焙烧温度低于550℃时,HZSM-5表面的B酸量(0.745—0.727mmol/g)基本上与根据骨架铝计算的理论值(0.735mmol/g)相吻合,说明交换下来的酸与沸石骨架铝密切相关。这部分B酸与HZSM-5的TPD谱图中峰Ⅱ相对应,说明它们是沸石表面的强酸中心,L酸与其它与骨架铝无直接联系的酸是较弱的酸中心。HZSM-5的催化活性随表面B酸量的下降而有规律的下降,而经Na~+充分交换后,用TPD测定的酸量与其催化活性基本无关的事实,说明酯化和乙醇缩合反应主要是在B酸中心上进行的。     

A weak cation-exchange phase for the separation of biogenic amines by open tubular liquid chromatography

Summary The preparation and performance of a weak cation-exchange stationary phase for Open Tubular Liquid Chromatography (OT-LC) was investigated. The stationary phase was prepared in 5.4 μm I.D. fused silica capillaries byin situ photopolymerization of a mixture of silicon acrylate and acrylic acid. The influence of pH, counter ion concentration and organic modifier concentration of the mobile phase on the retention was studied with catecholamines as test solutes using LIF detection. Other biological amines like amino acids, small peptides and nucleic acid derivatives could be separated on this stationary phase as well. The kinetic performance of the stationary phase was studied with several cations and neutral solutes.     

高亲水性强阳离子交换色谱填料的制备及其在蛋白质分析中的应用

以具有双孔结构的聚甲基丙烯酸环氧丙酯(PGMA)微球为基质,以葡萄糖进行表面亲水改性,制备了强阳离子交换色谱填料,并将其用于复杂生命体系中生物大分子的快速而高效的分离、分析与纯化。葡萄糖亲水改性增进了填料的生物相容性,提高了蛋白质样品的回收率;双孔结构及较高的比表面积赋予填料良好的柱渗透性和样品负载量。以标准蛋白质为样品,考察了该填料对生物样品的分离性能。以100 mm×4.6 mm的色谱柱分离4种蛋白质,在6 min内实现了基线分离;以溶菌酶为样品,填料的吸附容量为39.5 g/L,在蛋白质快速分离纯化分析中显示了良好的应用前景。     

一种弱阳离子交换材料的亲水模式糖肽富集新方法

亲水作用色谱(HILIC)材料在糖肽的富集与分离中得到越来越广泛的应用. 针对目前HILIC材料糖肽选择性不足的缺点, 发展新的糖肽富集方法十分必要. 本工作发展了一种商品化的弱阳离子交换材料(WCX)在亲水模式下对糖肽的富集方法. 首先考察了微固相萃取(SPE)模式下WCX上多肽保留的机理. 结果显示, WCX上糖肽的保留同时受乙腈含量和pH的影响. 将WCX用于牛胎球蛋白(fetuin)胰蛋白酶酶解液中糖肽的富集, 获得了39条糖肽信号. 当fetuin与牛血清白蛋白(BSA)酶解液以物质的量比1:5混合时, 富集到26条糖肽信号. 富集人免疫球蛋白(IgG)胰蛋白酶酶解液时获得25条糖肽信号, 1:5时获得23条糖肽信号. 实验说明WCX对唾液酸化和非唾液酸化糖肽的富集均有高选择性. 该方法拓展了WCX的应用范围, 丰富了HILIC材料的种类.     

L-色氨酸和L-苯丙氨酸在732树脂上的吸附平衡

研究了L-色氨酸和L-苯丙氨酸在732阳离子交换树脂上的单组分等温吸附平衡,分别采用Freundlich方程和Langmuir方程拟合吸附平衡数据.料液初始pH值介于3.5～6.5时,pH值对平衡吸附量影响不大,而料液中过多H+存在会降低氨基酸在树脂上的吸附量.当温度处于25～40℃范围,随着温度的升高,树脂的吸附量略有下降.在不同的pH和温度下,分别用Freundlich方程拟合L-色氨酸和L-苯丙氨酸平衡数据,其平均相对误差在3.63%～4.93%范围.     

手持技术数字化实验探究夹心式膜电池的创新改进*

借助手持技术,用阳离子交换膜代替盐桥,滤纸代替烧杯,将双液铜锌原电池改进为高效化、微型化的夹心式阳离子交换膜原电池。通过实验探究、微观分析得出阳膜电池具有电流示数大且较稳定、装置简易、操作方便、药品用量小、绿色无污染等优点。本实验不仅揭示膜电池的工作原理、还原高考膜电池实验、构建化学电源的基本模型,还贴近生活,提高学生的自主实验探究能力,培养学生宏观辨识与微观探析、科学探究与创新意识的核心素养。