同时测定海水中K+、Na+、Ca2+、Cl-的流动注射离子选择电极分析

建立了一种用于海水中K+、Na+、Ca2+、Cl-同时快速、自动测定的流动注射离子选择电极自动方法(FI-ISE-M),优化了方法的最佳条件:总离子强度调节液(TISAB)的组成为0.3 mmol/L K+、6.0 mmol/L Na+、1.4 mmol/L Ca2+、21.0 mmol/L Cl-及pH8.0的80 mmol/L的tris-H3BO3缓冲溶液,其流量为1.25mL/min;每次测定的样品用量仅为160μL,载流流量为1.42 mL/min,混合盘管长度为30cm(I.D.0.5 mm)。本方法的分析速度为100样/h,相对标准偏差为2.0%(n=11),标准添加回收率为94.9%～104.3%,测定范围分别为1.0～8.0 mmol/L K+、50～290 mmol/L Na+、3.2～16.0 mmol/L Ca2+、70～430 mmol/LCl-。本方法已应用于反渗透海水淡化系统的水质检测。     

离子色谱法同时测定大气可吸入颗粒物PM10中14种水溶性离子

采用离子色谱法同时测定了大气可吸入颗粒物PM10中的多种水溶性阴阳离子。样品采用超纯水超声萃取各种水溶性离子,优化的萃取溶液体积为40mL,萃取时间为15 min,萃取液用0.45μm纤维滤膜过滤,阴、阳离子分别采用响应的离子色谱柱分离,流动相分别采用3.6 mmol/L Na2CO3溶液+0.6 mmol/L NaHCO3溶液,2 mmol/L HNO3溶液,其中阳离子检测未使用抑制器,电导检测器检测。14种离子在一定浓度范围内线性关系良好,相关系数r都>0.999,F-,BrO3-,Cl-,NO2-,Br-,NO3-,PO42-,SO42-等8种阴离子的检出限分别为1.5,7.5,1.6,4.2,6.5,12.5,10.4,3.3μg/L,Li+,NH4+,Na+,K+,Mg2+,Ca2+等6种阳离子的检出限分别为4.6,12.3,8.5,19.8,12.4,17.9μg/L,平均回收率为92.3%~99.7%,标准偏差小于5%。方法适用于同时测定PM10中的多种水溶性离子。     

亚甲基蓝及NH4+,Na+,K+与SiO2的表面配位常数测定

采用动电位、等温吸附方法研究了不同pH条件下SiO2的表面电性和对有机染料-亚甲基蓝的吸附行为,运用WinSGW软件计算得出亚甲基蓝在SiO2颗粒表面配位常数.研究发现亚甲基蓝通过静电和氢键作用吸附,相应的化学反应模型和表面配位常数分别为≡Si2O-+MB+≡Si2OMB(lg K=4.48)和≡SiOH+MB+≡SiOHMB+(lg K=2.30).在此基础上研究了一价阳离子NH+4,Na+,K+对亚甲基蓝在SiO2表面吸附的影响,根据WinSGW软件模拟得到的NH+4,Na+,K+与SiO2表面的配位常数分别为:≡Si2O-+M+≡Si2OM[lg K=3.76,2.73,2.58(M+=NH+4,Na+,K+).在铵根离子浓度高时,还会在表面上发生≡SiOH+NH3+MB+≡SiOHNH3MB+(lg K=6.69)化学反应而生成包含有三种组分的≡SiOHNH3MB+表面三元配合物.研究结果可为了解有机染料和氨氮在被污染土壤和水体中的分布提供一定的理论依据.     

五元交互体系Li+,Na+,K+//CO32-,Cl--H2O在298.15K的相平衡研究

针对西藏扎布耶盐湖卤水组成,采用等温溶解平衡法研究了五元交互体系Li+,Na+,K+//CO32-,Cl--H2O于298.15K时的相平衡,并绘制了相图(空间立体图和Li2CO3饱和的投影图).结果表明,该五元体系相图含有7个结晶区、13条单变量线和4个无变量点.7个结晶区由6个单盐结晶区和1个复盐结晶区组成,分别为LiCl·H2O,NaCl,KCl,Li2CO3,K2CO3·3/2H2O,Na2CO3·10H2O和NaKCO3·6H2O,没有形成固溶体和天然碱(Na2CO3·NaHCO3·2H2O).4个无变量点标记成K1,K2,K3和K4,所对应的平衡固相盐分别是:Li2CO3+NaKCO3·6H2O+Na2CO3·10H2O+KCl,Li2CO3+NaKCO3·6H2O+K2CO3·3/2H2O+KCl,Li2CO3+NaCl+KCl+LiCl·H2O和Li2CO3+NaCl+Na2CO3·10H2O+KCl.     

Ni2+和Cd2+跨人红细胞膜的比较研究

以往对金属离子跨红细胞膜转运多集中在体内的宏量金属离子, 如Na+, K+, Ca2+, Mg2+及某些必需的重金属元素Fe2+, Cu2+, Zn2+等[1～3], 对其它重金属离子的跨膜转运研究较少. 我们曾研究了具有不同电荷的Co(Ⅲ)配合物的红细胞摄入动力学及机理[4]. 在此基础上进一步选择离子电荷数相同, 但电子组态不同的两个金属离子Ni2+和Cd2+为研究对象. Ni2+为d8组态, 动力学上是惰性的, 为体内必需的微量元素; 而Cd2+为d10组态, 动力学上是活性的, 却为有毒重金属, 本研究比较了它们跨人红细胞膜传递的动力学以及其与人红细胞作用的差异性.     

新型荧光粉Ca2Zn4Ti16O38∶Pr3+，Na+的合成和红色长余辉性质

采用溶胶-凝胶法合成了Ca2Zn4Ti16O38:Pr3+,Na+荧光粉.通过X-射线衍射和荧光光谱表征样品的物相组成和发光性质.X射线衍射(XRD)分析表明添加适量的H3BO3作助熔剂有利于形成良好的Ca2Zn4Ti16O38晶体结构.荧光光谱表明Ca2Zn4Ti16O38:Pr3+,Na+在可见光区(450～495 nm)呈现Pr3+离子的4f→4f厂特征激发光谱以及613 nm(1D2→3H4)和644 nm(3P0→3F2)特征发射.Ca2Zn4Ti16O38:Pr3+,Na+被可见光(475 nm)激发产生的(3P0→3F2)(644 nm)红色发射呈现出极慢的衰减特性.Ca2Zn4Ti16O38:Pr3+,Na+是一种新型的可见光激发红色长余辉荧光粉.     

Dy3+单掺及Dy3+,Er3+共掺GdVO4纳米粒子的制备及发光性能的研究

用水热法制备了Dy3+单掺及Dy3+,Er3+双掺GdVO4纳米荧光粉,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FTIR)和荧光(FL)光谱对合成样品的结构、形貌和发光性能进行表征;探讨了Dy3+掺杂浓度、络合剂对GdVO4:Dy3+纳米晶的结构、形貌和发光性能的影响;考察了不同波长的近红外光和紫外光激发的GdVO4:Dy3+,Er3+,得到不同颜色的上转换和下转换荧光光谱。以760~830 nm近红外光和210~380 nm紫外光激发GdVO4:Dy3+纳米晶,可获得Dy3+蓝绿色双模发光;其中蓝光来自于Dy3+离子的4F9/2→6H15/2跃迁,绿光由Dy3+离子4F9/2→6H13/2跃迁产生。     

离子色谱法测定中药女贞子浸煮液中的碱金属和碱土金属

用离子色谱法测定了中药女贞子水浸煮液中K+、Na+、Ca2+、Mg2+的含量,色谱柱为IonPAC CS 12A(4 mm×250 mm)阳离子交换柱,淋洗液为11.0 mmol/L的硫酸溶液,流速1.00mL/min,电导检测器检测。结果表明,4种离子的检出限分别为:Na+0.021 mg/L,K+0.020 mg/L、Mg2+0.015 mg/L,Ca2+0.100 mg/L,相对标准偏差在0.72%~3.92%之间,回收率为98.3%~103.1%。结论:该法操作简便、快速,准确,为测定其它中药中Na+、K+、Mg2+、Ca2+的含量提供了一种有效的方法。     

ICP-AES法测定油田采出水中钙、镁

为确定ICP-AES法测定油田采出水中Ca,Mg元素的影响因素以及消除方法,研究了不同浓度阳离子和油含量对Ca,Mg元素测定的影响。采用湿式消解法处理油田采出水对油进行消解,并通过测定电导率选择合适的基体匹配系列测定样品。Ca,Mg元素的检出限分别为0.01和0.002 mg/L,Na+,K+的存在测定结有较大影响,而在油田采出水油含量变化范围内,稀释后油含量对测定结果影响较小。通过基体匹配系列能降低Na+,K+的干扰,湿式消解法可消除油对测定的影响;方法的加标回收率在98%~102%之间,RSD在0.5%~2.1%之间,ICP-AES法与滴定法测定值进行比较,差异无统计学意义(P0.05),说明所建立的方法是一种适合油田采出水中Ca,M g元素定量测定的方法。     

ICP–AES法测定黄瓜中的8种元素

利用微波消解法消解样品,建立电感耦合等离子体原子发射光谱(ICP–AES)法,对大黄瓜和荷兰小黄瓜两种黄瓜样品中的K,Ca,Mg,Fe,Mn,Cu,Zn,Se 8种元素进行含量测定。K+线性范围为0~100μg/m L,Ca2+,Mg2+线性范围为0~20μg/m L,其余离子线性范围为0~2.0μg/m L,相关系数在0.999 6~1.000 0之间,样品加标回收测定结果的相对标准偏差均小于5%(n=6),加标回收率为93.4%~103.2%。结果表明人体所必须的常量元素K,Ca,Mg在两种黄瓜样品中均大量存在,荷兰小黄瓜中K,Ca,Cu,Mn的含量高于大黄瓜,而Fe,Mg,Se的含量低于大黄瓜,Zn在两种黄瓜样品中含量相当。该法可用于测定黄瓜样品中的K,Ca,Mg,Fe,Mn,Cu,Zn,Se元素含量。     

Estimation of Li+, K+ and Ca2+ Complexation with [12] crown-4, [15] crown-5 and [18] crown-6 Using a Na+ ISE in Dioxane-Water, Part IV*

 The (1:1) Na⁺ equilibrium constants, Ke1, of macrocyclic ethers of [12]crown-4, [12]crown-5 and [18]crown-6 were determined with a Na⁺ ISE in the presence of a second cation e.g. Li⁺, K⁺ and Ca²⁺ in dioxane/water (50/50). We estimated the (1:1) equilibrium constants, K e2 of the macrocyclic ethers with Li⁺, K⁺ and Ca²⁺ by this way. The binding selectivity of a macrocyclic ether between two cations was estimated in the same binary solvent mixture where the water hydration role is diminished. Results showed clearly the effect of macrocyclic size and cation radii in a solution. Received October 27, 1998. Revision March 22, 1999.     

Effect of matrix modifier and furnace material on the determination of traces of fluoride by electrothermal molecular absorption spectrometry of aluminum monofluoride

In the determination of fluoride by AlF absorbance measurements, the interference from strontium nitrate is avoided by using magnesium nitrate or barium nitrate added to aluminum solution as the matrix modifier. The effects of the graphite-furnace material on AlF absorbance are investigated. Glassy carbon and synthetic carbon gave longer furnace lifetimes and better sensitivity than the other materials tested. The maximum sensitivity (4.2 μg ml^?1 fluoride for 0.0044 absorbance with a 10-μl injection) was obtained with synthetic carbon. The r.s.d, was <5% for 0.1 μg ml^?1 fluoride (n=10). Na⁺, K⁺, Pb²⁺, Zn²⁺, Cu²⁺ and Ag⁺ did not affect the measurements up to 500 μg ml^?1, but Ni²⁺, Co²⁺, Fe²⁺, Sr²⁺ and especially Ca²⁺ depressed the absorbance.     

Nonempirical conformational analysis of oubaine molecule chelate complexes with Ca2+ and possible mechanism of modulation of transductor function of Na+,K+-ATPhase

Complete conformational analysis of chelate complex of oubaine molecule with Ca²⁺ in 1:1 stoichiometry is carried out. Complete ab initio optimization of geometric parameters of all possible structures of the complexes is performed in the framework of restricted Hartree-Fock method with 6–31G* basis using GAMESS program. Influence of the complex formation on the steric structure and electronic structure of oubaine molecule is analyzed. Oubaine molecule is found capable of binding Ca²⁺ by two modes. Mechanism of binding of oubaine molecule with transductor site of Na⁺,K⁺-ATPhase is proposed: ligand-receptor interaction is assumed to be realized in account of formation of trial complex oubaine-Ca²⁺-Na⁺,K⁺-ATPhase, with main contribution to the interaction energy of ion-ion bonds formation between Ca²⁺ and nucleophilic functional groups in the composition of the mentioned binding site of Na⁺,K⁺-ATPhase.     

A new sulfonamide derivative as magnesium ion receptor: N-tosyl-2,6-diisopropyl-4-(2,3-dimethoxylbenzoylamide)aniline

N-Tosyl-2,6-diisopropyl-4-(2,3-dimethoxylbenzoylamide)aniline (1) has been synthesized and its metal ion (Na⁺, K⁺, Ca²⁺, Mg²⁺) coordinating properties investigated by FT-IR, ESI-MS, and ¹H NMR methods. Among the tested metal ions, the overall stability constant (log K) for Mg²⁺ (6.89) is the highest (Na⁺, 5.64; K⁺, 5.43; Ca²⁺, 5.51) in 10% water/THF at 25.0 ± 0.5 °C determined by UV-vis spectroscopy, indicating that 1 is a potent ionophore for Mg²⁺ ion.     

Interaction of a Schiff-base fluorescent sensor with Al3+: experimental and computational studies

A fluorescent Al³⁺ chemo-sensor, 1-phenyl-3-methyl-5-hydroxypyrazole-4-acetone-(3′,4′-dimethylpyrrole-2′-formyl) hydrazone (L), has been synthesized and characterized. L can detect Al³⁺ in ethanol solution with a significant fluorescence enhancement of a turn-on ratio over 155-fold due to the formation of a 1?:?1 complex which is based on the molar ratio between L and Al³⁺ ions, and the 1?:?1 stoichiometric complexation can be obtained from density functional theory calculations. No significant interference of other metal ions such as Na⁺, K⁺, Mg²⁺, Ca²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Co²⁺, Cu²⁺, Fe³⁺, Cr³⁺, Pb²⁺, and Ag⁺ was found. The detection limit for Al³⁺ was 5?×?10^?9?M in ethanol.     

Complexation Properties of a Carbon-Bridged Cryptand with Metal Ions in Aqueous Solution at 25°C

Abstract

Thermodynamic quantities (log K, ΔH, and ΔS) for the interactions of a carbon-bridged cryptand with Li⁺, Na⁺, K⁺, Ca²⁺, Sr²⁺, Ba²⁺, and Pb²⁺ were determined at 25° C by calorimetric titration in aqueous solution. The cryptand forms complexes with Na⁺, Sr²⁺, Ba²⁺, and Pb²⁺ with log K ≤ 2. Complexation was not detected for Li⁺, K⁺, and Ca²⁺. Weak interactions with Li⁺ and K⁺ and a log K value of 2.4 for Na⁺ suggest that the cavity size of the cryptand is close to that of Na⁺ but too small for K⁺ and too large for Li⁺. The carbon-bridged cryptand selectively binds Sr²⁺ (log K = 3.2) over Ca²⁺ and Ba²⁺ by more than one order of magnitude.     

Use of zwitterionic micelles in the eluent II: a new approach to ion chromatographic analysis of inorganic cations in biological fluids with direct sample injection

A new ion chromatographic (IC) technique has been developed for the determination of inorganic cations in biological fluids with direct sample injection. This involved the use of a mixed zwitterionic-micelle/electrolyte solution as an eluent. The proteins in the sample became bound to the zwitterionic micelles in the eluent and were thus eliminated from the column. The cations were separated by cation exchange. This method is ideal for the on-line, simultaneous determination of common inorganic cations (Na⁺, NH₄ ⁺, K⁺, Mg²⁺, and Ca²⁺) in urine and serum samples. Such an application was demonstrated experimentally. Non-suppressed conductivity was used for analyte detection. The detection limits obtained using this IC system were 2.94, 5.22, 34.9, 32.6, and 56.7 μg/L for Na⁺, NH₄ ⁺, K⁺, Mg²⁺, and Ca²⁺, respectively.     

Effects of La<Superscript>3+</Superscript> and Eu<Superscript>3+</Superscript> on outward potassium channels in Vicia guard cells

Effects of La³⁺ and Eu³⁺ on outward potassium channels (K_out⁺) in Vicia guard cells have been studied by patch clamping technique. Extracellular La³⁺ inhibited K_out⁺ currents with a half-inhibition concentration (IC₅₀) of 81 μmol·L⁻¹. Interestingly, intracellular La³⁺ activated K_out⁺ currents at a free concentration of 1.13 × 10⁻¹⁴ mol·L⁻¹, and inhibited K_out⁺ currents at a free concentration of 5.86 × 10⁻¹⁴ mol·L⁻¹. Extracellular Eu³⁺ also activated K_out⁺ currents at concentrations of 10 μmol·L⁻¹ and 50 μmol·L⁻¹, and inhibited K_out⁺ currents at concentrations of more than 1 mmol·L⁻¹. The effects of La³⁺ and Eu³⁺ on K_out⁺ currents may contribute to regulation of the plant water status, which may be one of the mechanisms of the biological effect of rare earth elements.     

Ion chromatographic method for the determination of cations of group IA and IIA in water samples, pharmaceuticals and energy drinks by non-suppressed conductometric detection

An efficient ion chromatographic (IC) method was developed for the simultaneous quantitative determination of Li⁺, Na⁺, NH₄ ⁺, K⁺, Cs⁺, Ca²⁺, Mg²⁺, Sr²⁺, Ba²⁺ and Be²⁺ in energy drinks, pharmaceutical and drinking water samples by non-suppressed conductometric detection. The separation of ten cations including ammonium was achieved using a cation-exchange column and low conductivity mobile phase. The mobile phase consisted of tartaric acid, dipicolinic acid and boric acid. The separation of the cations was completed in less than 18 min, with a flow rate of 1.2 mL min⁻¹. The separation was not affected by the existence of cations Co²⁺, Cr³⁺, Cd²⁺, Cu²⁺, Bi³⁺, Ag⁺, Fe³⁺ and Zn²⁺ in concentrations up to 20 mg L⁻¹. Using an injection volume of 20 μL the obtained detection limits were 0.003 mg L⁻¹, 0.02 mg L⁻¹, 0.01 mg L⁻¹, 0.01 mg L⁻¹, 0.10 mg L⁻¹, 0.01 mg L⁻¹, 0.02 mg L⁻¹, 0.02 mg L⁻¹, 0.003 mg L⁻¹ and 0.1 mg L⁻¹, for Li⁺, Na⁺, NH⁴⁺, K⁺, Cs⁺, Ca²⁺, Mg²⁺, Sr²⁺, Be²⁺ and Ba²⁺ respectively. The intra-day repeatability (RSD%, n=5) ranged from 1.1% to 4.8%, and the inter-day (n=5) between 1.8% and 5.4% respectively. The method was applied to the analysis of various bottled and tap water, pharmaceutical preparations and energy drinks commercially available.      

Zur Reproduzierbarkeit von Na+-, K+- und Ca2+-selektiven Diskelektroden in Abh?ngigkeit vom Anzeigefehler des verwendeten Potentialme?ger?tes

Zusammenfassung Für die Na⁺-, K⁺- und Ca²⁺ -Bestimmung mit ionenselektiven Diskelektroden im medizinischen Bereich empfiehlt sich die Zweipunkteichung. Die mit diesem Verfahren erzielbare Reproduzierbarkeit wird theoretisch aufgrund des Ablesefehlers am Meßinstrument berechnet und mit experimentellen Werten verglichen. Die theoretisch berechneten und experimentellen Standardabweichungen liegen für 1-wertige Ionen bei 0,3 % und für 2-wertige bei 0,6 %. Die Genauigkeit wird nicht durch die Elektroden, sondern die gegenwärtig verfügbaren Meßgeräte begrenzt.

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On the reproducibility of Na⁺-, K⁺- and Ca²⁺-selective disc electrodes as dependent on the indicating error of the potential measuring device

Summary In clinical analysis it is recommendable to use a two-point calibration for the determination of Na⁺, K⁺ and Ca²⁺ ions by ion-selective disc electrodes. The accuracy, which can be obtained by this calibration method, is treated theoretically, and the results are compared with experimental data. Theoretical and experimental standard deviations are in very good agreement, with 0.3 % for Na⁺ and K⁺ and 0.6 % for Ca²⁺. The precision is limited by the measuring instrument and not by the disc electrodes.

Wir danken dem Fonds der Chemischen Industrie, dem Bundesministerium für Forschung und Technologie der Bundesrepublik Deutschland und der Dr. E. Fresenius KG, Bad Homburg v.d.H., für die Unterstützung der Arbeiten.