离子色谱法测定土壤中的Cl~–和SO_4~(2–)

采用离子色谱法测定土壤浸提液中的Cl–和SO42–。选择2.0 mmol/L Na2CO3–1.3 mmol/L NaHCO3混合液为淋洗液,流速为2 mL/min,在此条件下,Cl–保留时间为1.96 min,SO42–保留时间约为12.26 min,Cl–,SO42–的质量浓度分别在2~8,10~30 mg/L范围内与色谱参数线性相关,相关系数分别为0.999 4和0.999 7,Cl–,SO42–的平均加标回收率分别为93.8%,105.4%,测量结果的相对标准偏差均小于1%(n=6)。该法适用于土壤中Cl–和SO42–的测定。     

二维离子色谱法同时测定环境水样中的碘离子、硫氰酸根和高氯酸根

建立了二维离子色谱法同时测定环境水样中的碘离子、硫氰酸根离子和高氯酸根离子的方法。先采用常规阴离子色谱柱(IonPac AS16, 250 mm×4 mm)将水样中的碘离子、硫氰酸根离子和高氯酸根离子与干扰离子进行分离。样品溶液通过抑制器后,将含有碘离子、硫氰酸根离子和高氯酸根离子的淋洗液导入富集柱(MAC-200, 80 mm×0.75 mm),再通过毛细管阴离子色谱柱(IonPac AS20 Capillary, 250 mm×0.4 mm)进行分离和定量分析。方法的线性范围为0.05～100 μg/L,相关系数达到0.9999,检出限为0.02～0.05 μg/L。样品中碘离子、硫氰酸根离子和高氯酸根离子的加标回收率在85.1%～100.1%之间,回收率的相对标准偏差(RSD)(n=6)在1.7%～4.9%之间。该法试剂用量小,灵敏度比常规离子色谱提高30～40倍,同时去除了样液中的高浓度基体杂质,适用于水样中低含量碘离子、硫氰酸根离子和高氯酸根离子的检测。     

甲苯间接电氧化作用──铂电极上Ag（Ⅰ）在Mn（Ⅱ）／Mn（Ⅲ）电偶转化过程中的催化作用

酸性溶液中铂电极表面生成的Ａｇ（Ⅱ）能氧化溶液中的Ｍｎ（Ⅱ）为Ｍｎ（Ⅲ）．甲苯氧化反应的速率对Ａｇ（Ⅰ）与Ｍｎ（Ⅲ）皆为一级反应。     

离子色谱法同时测定氟、磷酸根和六氟磷酸根离子

氟、磷酸根和六氟磷酸根离子在流速为0．25ml.min^-1,淋洗液为0．001mol.l^-1Na2CO3和0．005mol.L^-1NaOH溶液,在离子色谱仪上能较好地分离。氟,磷酸根和六氟磷酸根离子的检出限分别为7．29,70．5和295ng.ml^-1,该方法具有良好的线性,测定结果有较好的重现性,样品测定结果满意。     

聚冠醚的合成和性质——Ⅵ.聚冠醚为载体的碱金属离子选择性电极

本文报道以含有12-冠-4、15-冠-5和18-冠-6结构单元的双酚A型聚冠醚为载体的钠、钾和铯离子选择性电极的制备及电极响应特性的研究。结果表明三种电极都有较好的Nernstian响应特性和对碱金属及碱土金属的良好选择性。     

Potentiometric Measurements in Non-Aqueous Media Using Bromide and Iodide Ion Selective Membrane Electrodes

Abstract

Solid membrane bromide and iodide ion selective membrane electrodes were evaluated for their performance in non-aqueous media. The electrodes were evaluated in several alcohols and glacial acetic acid.     

离子色谱法快速分析饮用水中的四种阴离子

用Dionex DX-120离子色谱仪对饮用水中F^-1、Cl^-1、NO3^-1及SO4^2- 4种阴离子进行测定，分析中采用了Dionex AS14阴离子分离柱对上述4种阴离子进行分离。作者等对Dionex公司所建议的色谱条件作了修改和改进，使方法的分析效能大大提高，达到了快速分析的要求。按改进后的色谱条件，4种离子的分离度达到了3．9的数值，4种阴离子测定结果的相对标准偏差值均小于2．5％，回收率在94％-108%之间。对有标准值的水样用此文的方法和国家标准方法同时进行比较分析，并用卜检验法对两方法的结果的可靠性，以及与标准值的比较，结果表明各离子（Cl^-1、NO3^-1及SO4^2-）的测定结果之间均无显著性差异。     

含嘧啶环的双冠醚——V.双冠醚为载体的碱金属离子选择性电极的研究

本文报道由5-硝基-6-三氟甲基嘧啶环桥联苯并-12-冠-4、苯并-15-冠-5和苯并-18-冠-6的三种新的双冠醚的合成。用它们作为载体分别制成钠、钾和铯离子选择性电极，测定了电极的响应功能、选择性系数和适用的pH范围。结果表明三种电极都有较好的性能。     

Solvent-dependent chromogenic sensing for Cu and fluorogenic sensing for Zn and Al: a multifunctional chemosensor with dual-mode

A new multifunctional chemosensor 1 was synthesized and characterized by spectroscopic tools along with a single crystal X-ray crystallography. It can exhibit selective recognition responses toward Cu²⁺, Zn²⁺ and Al³⁺ in different solvent systems with bimodal methods (colorimetric and fluorescence). This sensor 1 detected Cu²⁺ ions through a distinct color change from colorless to yellow in aqueous solution. Interestingly, the receptor 1 was found to be reversible by EDTA. The detection limit (11 μM) of 1 for Cu²⁺ is much lower than WHO guideline (30 μM) in drinking water. In addition, the sensor 1 showed significant fluorescence enhancements in the presence of Zn²⁺ ion and Al³⁺ ion in two different organic solvents (DMF and MeCN), respectively. The binding modes of the three complexes were determined to be a 1:1 complexation stoichiometry through Job plot, ESI-mass spectrometry analysis, and ¹H NMR titration.     

Different binding thermodynamics of Ni2+, Cu2+, and Zn2+ to bacitracin A1 determined by capillary electrophoresis

Thermodynamics of the binding of Ni(2+), Cu(2+) and Zn(2+) to bacitracin A(1) was studied by capillary electrophoresis measuring the peptide effective mobility at different pH in the presence of increasing concentration of the three ligands. The affinity follows the order Ni(2+) > Cu(2+) > Zn(2+), with association constant values of (2.3 +/- 0.1)x10(4), (4.9 +/- 0.2)x10(3), and (1.5 +/- 0.1)x10(3) M(-1), respectively. The only model able to rationalize mobility data implies that metal ion binds to the P(0) peptide form. Moreover, mobility values indicated a change of bacitracin A(1) acidic properties on Ni(2+) and Cu(2+) binding, with a shift of the pK(a) of N-terminal Ile-1 from 7.6 to about 5 and of the pK(a) of the delta-amino group of D-Orn-7 from 9.7 to about 7. Even though on Zn(2+) binding a shift of the N-terminal Ile-1 pK(a) was observed, restrictions in the pH range suitable for investigation, due to precipitation phenomena, did not allow establish if the shift of D-Orn-7 lateral chain pK(a) also occurred. Nonetheless, if present, the shift should be limited to the 7.8-9.7 range. Mobility data indicated that the Stokes radius of the complexes is ca. 3 A lower than that of the free peptide. The present results indicate that metal-ion binding to bacitracin A(1) is more complex than previously assumed.     

铵盐离子对中有机阴离子交换排序的研究

本文用测定ClO_4~-离子选择性电极电势选择性系数K_(ij)~(pot)的方法,研究了七种长链季铵大阳离子与十余种有机阴离子在水、油两相中交换能力的排序。即: C_2O_4~-相似文献   

Strategies for generating peptide radical cations via ion/ion reactions

Several approaches for the generation of peptide radical cations using ion/ion reactions coupled with either collision induced dissociation (CID) or ultraviolet photo dissociation (UVPD) are described here. Ion/ion reactions are used to generate electrostatic or covalent complexes comprised of a peptide and a radical reagent. The radical site of the reagent can be generated multiple ways. Reagents containing a carbon–iodine (C―I) bond are subjected to UVPD with 266‐nm photons, which selectively cleaves the C―I bond homolytically. Alternatively, reagents containing azo functionalities are collisionally activated to yield radical sites on either side of the azo group. Both of these methods generate an initial radical site on the reagent, which then abstracts a hydrogen from the peptide while the peptide and reagent are held together by either electrostatic interactions or a covalent linkage. These methods are demonstrated via ion/ion reactions between the model peptide RARARAA (doubly protonated) and various distonic anionic radical reagents. The radical site abstracts a hydrogen atom from the peptide, while the charge site abstracts a proton. The net result is the conversion of a doubly protonated peptide to a peptide radical cation. The peptide radical cations have been fragmented via CID and the resulting product ion mass spectra are compared to the control CID spectrum of the singly protonated, even‐electron species. This work is then extended to bradykinin, a more broadly studied peptide, for comparison with other radical peptide generation methods. The work presented here provides novel methods for generating peptide radical cations in the gas phase through ion/ion reaction complexes that do not require modification of the peptide in solution or generation of non‐covalent complexes in the electrospray process. Copyright © 2015 John Wiley & Sons, Ltd.     

Er~(3 ),Ho~(3 )和Tm~(3 )在硫氧化钆中的余辉发光

非放射性长余辉磷光粉作为美化和清洁光源在发光陶瓷、交通安全标志、紧急突发事件的照明设施、工艺美术涂料等众多领域得到越来越广泛的应用,引起人们的重视.到目前为止,文献报道的稀土长余辉磷光体的激活离子主要有铕离子(Eu3+和Eu2+[1-4]、三价铈离子(Ce3+)[5]、三价铽离子(Tb3+)[6]、三价镨离子(Pr3+)[7]、三价钐离子(Sm3+)[8].Ho3+,Er3+,Tm3+等稀土离子作为红外上转换发光材料的激活离子[9～12],而关于它们的长余辉发光的报道极少.最近,雷炳富等在Tm3+离子[13]激活的硫氧化钇体系中发现了长余辉发光.在此,我们通过高温固相法合成了Er3+,Ho3+和Tm3+掺杂的硫氧化钆长余辉磷光粉,观察到该体系中迄今未见文献报道的Er3+,Ho3+和Tm3+离子的长余辉发光.     

Er3+，Ho3+和Tm3+在硫氧化钆中的余辉发光

The new Er^3 , Ho^3 and Tm^3 doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photolumineseenee spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S:Er^3 , Mg, Ti showed typical transitions of Er^3 at 528(2H11/2→4I15/2), 548 (^4S3/2 →^4I15/2) and 669 nm (^4F9/2→^4I15/2). In the afterglow spectra of Gd2O2S: Ho^3 , Mg, Ti,typical transitions of Ho^3 at 546 nm (^5S2→^5I8), 651 and 661 nm (^2F5→^5I8) were observed. In Gd2O2S:Tm^3 , Mg,Ti, the afterglow emission at 800 nm (^1G4→^3H5) of Tm^3 was seen. The meehnism and model of afterglow energy transfer were proposed.     

Smart DNA Hydrogel Integrated Nanochannels with High Ion Flux and Adjustable Selective Ionic Transport

Nanochannels based on smart DNA hydrogels as stimulus‐responsive architecture are presented for the first time. In contrast to other responsive molecules existing in the nanochannel in monolayer configurations, the DNA hydrogels are three‐dimensional networks with space negative charges, the ion flux and rectification ratio are significantly enhanced. Upon cyclic treatment with K⁺ ions and crown ether, the DNA hydrogel states could be reversibly switched between less stiff and stiff networks, providing the gating mechanism of the nanochannel. Based on the architecture of DNA hydrogels and pH stimulus, cation or anion transport direction could be precisely controlled and multiple gating features are achieved. Meanwhile, G‐quadruplex DNA in the hydrogels might be replaced by other stimulus‐responsive DNA molecules, peptides, or proteins, and thus this work opens a new route for improving the functionalities of nanochannel by intelligent hydrogels.     

含嘧啶环的双冠醚——Ⅲ.用双冠醚作载体的PVC膜离子选择性电极性质的研究

合成了九种用嘧啶环桥联的新的双冠醚,其中分别含有苯并-12-冠-4、(1、47)、苯并-15-冠-5(2、5、8)和苯并-18-冠-6(3、6、9 )。用它们作为载体分别制成钠、钾和铯离子选择性电极,测定了电极的选择性系数。结果表明,电极(7)(8)(9)具有较好的性能。     

Die Kristallstrukturen von [Ph3PMe]Cl·CH2Cl2, [Ph4P]NO3·CH2Cl2 und [Ph4P]2[SiF6]·CH2Cl2

Crystal Structures of [Ph₃PMe]Cl·CH₂Cl₂, [Ph₄P]NO₃·CH₂Cl₂, and [Ph₄P]₂[SiF₆]·CH₂Cl₂ The crystal structures of the title compounds are determined by X‐ray diffraction. In all cases, the included dichloromethane molecules as well as the phosphonium cations are involved to form hydrogen bridges with the anions. [Ph₃PMe]Cl·CH₂Cl₂ ( 1 ): Space group , Z = 2, lattice dimensions at 100 K: a = 890.3(1), b = 988.0(1), c = 1162.5(1) pm, α = 106.57(1)°, β = 91.79(1)°, γ = 92.60(1)°, R₁ = 0.0253. [Ph₄P]NO₃·CH₂Cl₂ ( 2 ): Space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1057.0(1), b = 1666.0(1), c = 1358.9(1) pm, β = 100.10(1)°, R₁ = 0.0359. [Ph₄P]₂[SiF₆]·CH₂Cl₂ ( 3 ): Space group , Z = 2, lattice dimensions at 193 K: a = 1063.9(1), b = 1233.1(1), c = 1782.5(2) pm, α = 76.88(1)°, β = 83.46(1)°, γ = 72.29(1)°, R₁ = 0.0332.     

Highly Selective Potentiometric Oxalate Ion Sensors Based on Ni(Ⅱ) Bis-(m-aminoacetophenone)ethylenediamine

A plasticized PVC (polyvinyl chloride) membrane based oxalate ion selective electrode has been developed by using the condensation product of m‐aminoacetophenone and ethylenediamine. The transition metal complexes of the ligand N,N′‐bis(m‐aminoacetophenene)ethylenediamine (L) were synthesized and incorporated as ionophore for the synthesis of oxalate ion selective electrodes. Most appropriate result in terms of dynamic range, detection limit and response behavior was determined for the Ni(II) bis‐(m‐aminoacetophenone)ethylenediamine complex. The electrode demonstrated higher selectivity for oxalate ion with improved performance as compared to other carriers reported in past. The electrode shows Nernstian slope of (?28.5±0.4) mV·decade^?1 with improved linear range of 1×10^?1?1×10^?7 mol·L^?1, with a comparatively lower detection limit in the pH range of 5–10.5, giving a relatively fast response within 10 s and reasonable reproducibility. The selectivity coefficient was calculated using matched potential method and fixed interference method. The lifetime of the electrode was found to be nearly 2 months. The response mechanism and the interaction of oxalate ion with the complexes have been discussed by UV‐visible spectroscopic technique. Further the electrode was also successfully applied to determine the oxalate content in water samples.     

Conductance Studies of Alkali Metal Acetates in Acetic Acid-Acetonitrile Mixtures

Abstract

Conductance behaviour of lithium, sodium and potassium acetates in 20% and 80% acetic acid-acetonitrile mixtures at 35° have been measured. The association constants were evaluated by Fuoss-Hsia equation of 20% acetic acid-acetonitrile mixtures by making use of TDC-12 Computer. Shedlovsky, Fuoss-Kraus extrapolation techniques were also employed to evaluate the association constants for these salts in both the solvent mixtures. The association constants obtained by these three methods were compared. The results were discussed in terms of various theories of ion pair formation i.e., Bjerrum, Fuoss, Denison-Ramsay, and Ebeling, Kraft, Yokoyama and Yamatera. Hydrodynamic radius was also calculated to understand the solvation of ions, in 20% and 80% acetic acid-acetonitrile mixtures.