镁离子荧光探针

镁离子（Mg²⁺）在许多生理过程中扮演着重要的角色,因此对镁离子的选择性识别引起了人们极大的关注。本文综述了近年来镁离子荧光探针的最新研究进展。镁离子荧光探针体系主要分为：喹啉类、β-二酮类、冠醚/多醚类、羧酸类、荧光素/罗丹明类、配合物类、聚合物类和纳米材料类等。本文列举了每类探针分子代表性的化合物并总结比较了不同类型的镁离子荧光探针体系。     

Elektrochemische Untersuchungen über das enantiomerenselektive Verhalten von chiralen Ionophoren in flüssigen Membranen

Electrochemical Investigations of the Enantiomer Selectivity of Chiral Ionophores in Liquid Membranes The enantiomer selectivity of a series of chiral neutral ionophores was investigated by electrochemical methods using ionophore-solvent-polymer membranes and chiral ammonium salts as substrates. The potentiometrically determined enantiomer selectivities are in good agreement with the results of electrodialytic transport studies.     

A new approach to the analysis of nicarbazin and ionophores in eggs by HPLC/MS/MS

An HPLC/MS/MS method has been developed and validated for the quantification and confirmation of nicarbazin and ionophores (lasalocid, monensin, salinomycin, and narasin) in eggs. Nicarbazin is determined in the negative electrospray mode with a basic mobile phase that supports creation of negative ions. Consequently, our ability to maintain instrument sensitivity over time has significantly improved. The analysis of the ionophores is done in the positive electrospray mode using ammonium buffer for HPLC separation. Monitoring ammonium adduct parent ions resulted in enhanced sensitivity and better reproducibility of the ionophore analysis. The validation of this improved HPLC/MS/MS method for the detection of nicarbazin and the ionophores demonstrated excellent precision of below 10% RSD and lower LOD values (microg/kg) for nicarbazin (0.018), lasalocid (0.015), monensin (0.015), salinomycin (0.033), and narasin (0.039).     

Symmetrical, unsymmetrical and bridged calix[4]arene derivatives as neutral carrier ionophores in poly (vinyl chloride) membrane sodium selective electrodes

The complexing ability of a range of 19 symmetrical, unsymmetrical and bridged calix[4]arene derivatives having ester, ketone, amide, amine and thioether functionalities were determined by the picrate extraction method. On incorporating these calix[4]arene derivatives as neutral carrier ionophores in sodium-selective poly (vinyl chloride) membrane electrodes the performance was assessed on the basis of the sensitivity and selectivity over the alkali, alkaline earth metals and hydrogen and ammonium ions. The temperature dependence, response times and lifetimes were also determined. Four ionophores in particular gave excellent sensitivity and selectivity and lifetimes of > 200 days. These electrodes were then tested without additional lipophilic additives and one ionophore was incorporated into poly (vinyl chloride) membrane electrodes with plasticizing solvents of varying polarity.     

Application of azoles as neutral carriers in liquid membrane ion-selective pH electrodes

New synthetic H⁺-selective carriers, derivatives of pyrazole, have been used as ionophores in liquid membrane electrodes for pH measurements in the acidic range. Selectivity coefficients toward sodium, potassium and calcium have been determined in this range and they are comparable to or better than those for previously described carriers.     

Second harmonic studies of ions crossing liposome membranes in real time

The transport kinetics of the positively charged triphenylmethane dye, malachite green (MG(+)), across liposome bilayers effects the transport of monovalent inorganic cations when ionophores are present in the membrane. Three different types of ionophores characterized by different transport mechanisms have been studied. The ionophores are gramicidin A (gA) (a channel former), valinomycin (VAL) (a lipophilic cyclopeptide that encloses an alkali ion), and carbonyl cyanide-m-chlorophenylhydrazone (CCCP) (a weak acid that functions as a protonophore). The effects of these ionophores on the kinetics and extent of MG(+) crossing into the liposome, investigated using the interface selective second harmonic generation method, were found to be markedly different.     

Binding and Ionophoric Properties of Polythioamide Compounds. Ag(I) and Hg(II) Selectivities

The synthesis of tetrathiolactams and related di- and tetrathioamide compounds is described. The formation constants of their heavy-metal complexes are determined by using the strong UV absorption of the thioamide chromophore. Extraction and transport abilities of tetrathioamide ionophores show selectivities for Ag(I) and Hg(II) cations over alkali, alkaline-earth or other heavy metal cations including transition metals such as Co(II).     

Synthesis and electrode properties of 19-membered azo- and azoxycrown ethers. Structure of dibenzo-19-azocrown-7

19-Membered azo- and azoxycrown ethers have been synthesized by reductive macrocyclization of respective bis-(nitrophenoxy)oxaalkanes. The behavior of these compounds as ionophores in ion-selective membrane electrodes has been studied. The structure of the 19-membered dibenzoazocrown ether has been determined.     

Hydrogen-Bonding Ionophores for Inorganic Anions and Nucleotides and Their Application in Chemical Sensors

The potential and limits of hydrogen-bonding ionophores and their use in chemical sensors are discussed. Several hydrogen-bonding bis-thiourea ionophores have been found to complex inorganic anions, among them most strongly H2PO4-. Using such ionophores, ion-selective electrodes for chloride and sulfate have been developed. Furthermore, hosts that bind nucleotides with up to five hydrogen bonds have been synthesized. They have been applied in nucleotide selective electrodes, optodes and voltammetric sensors mimicking ion channels.     

Responses of H(+) selective solvent polymeric membrane electrodes fabricated from modified PVC membranes

Potentiometric responses of a novel class of pH sensitive ionophores, namely several phenoxazine derivatives, were tested in different modified PVC matrices. The ionophores were compounded into liquid membranes as usual or were covalently coupled to the polymeric matrix. The general analytical performance of the membranes and other membrane characteristics (i.e., resistance and response time, as measures of membrane decomposition or structural changes) were followed in time. The transient responses of membranes with mobile ionophores in high molecular weight (HMW) and carboxylated PVC (PVC-COOH) were compared to those with immobilized ionophores. The response time of membranes with immobilized ionophores was found to be between those with mobile ionophores in HMW (fast response) and PVC-COOH (sluggish response). Accordingly, the rate of response was correlated primarily to the -COOH content of the membranes.     

Lead(II)-polyethoxylate-tetraphenyl borate compounds as ionophores in membranes of selective electrodes

Lead-selective electrodes were proposed on the basis of tetraphenyl borates of lead(II) complexes of polyhydroxyethylated nonylphenols with various number of hydroxyethyl groups. The composition and some physicochemical properties of the ionophores were determined. Electroanalytical properties of the proposed selective electrodes were examined.     

Synthesis and characterization of covalently immobilized bis-crown ether based potassium ionophore

The synthesis of a novel covalently immobilized crown ether based potassium ionophore is presented. Apart from previously proposed methods for the preparation of PVC linked ionophores based on the chemical modification of functionalized PVC polymers, the hereby proposed procedure involves the direct copolymerization of a suitable derivative of the bis-crown ether type potassium ionophore (BME 44) and vinyl chloride monomer. The analytical performance of the potentiometric ion selective electrodes incorporating the PVC bound ionophore were optimized and determined. Compared with electrodes based on other bis-crown ether type immobilized potassium selective ionophores a slightly improved logK(K, Na)(Pot) and a longer lifetime was found. Spectral imaging and chronoamperometry were used to study the mobility of different bis-crown ether derivatives in plasticized PVC membranes.     

对钠离子有选择性的中性载体

合成了十一种中性离子载体,用它们制成钠离子选择性电极,测定了电极的选择性系数并与文献报道的类似电极进行了比较。     

Extraction of Cupric Ions with Ionic Liquids Containing Polypyridine‐type Small Molecules or Peripherally Pyridine‐modified Dendrimers

The hydrophobic ionic liquid N‐butyl‐N‐methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP‐TFSA IL), which contains a series of flexible ionophores of polypyridine‐type small molecules or two rigid ionophores of peripherally pyridine‐modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine‐type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine‐modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.     

Ion-Selective Electrodes for the Determination of Nitrogen-Containing Medicinal Substances

Stoichiometric ratios and solubility products were determined for medicinal substance–tetraphenyl borate ion pairs. The influence of the nature of the medicinal substance cation incorporated into ionophores and the effect of the solvent–plasticizer on analytical characteristics were studied. The optimal composition of membranes was determined. Ion selective electrodes were used for the potentiometric determination of dimedrol, papaverine, novocaine, and lidocaine in medicinal forms.     

Ion-selective electrode for the determination of dimethylbenzylammonium ions

A sensor is proposed for the direct potentiometric determination of dimethylbenzylammonium in acid and neutral aqueous solutions. The sensor membrane is made of a polymeric composition on the basis of polyvinylchloride containing an ion associate and a solvent as a plasticizer. Salts of the tetraphenylborate anion and its derivatives served as ionophores. Basic electroanalytical parameters of the developed potentiometric sensors are studied and the pH range of their possible application is determined. The developed sensor is used as a reference electrode in the potentiometric titration of dimethylbenzylammonium with tetraphenylborate anions.     

Bestimmung von Stabilitätskonstanten in Ethanol für Li+-selektive Ionophore mittels differentieller Dampfdruckosmometrie

Determination of Stability Constants in Ethanol for Li⁺-selective Ionophores by Differential Vapour Pressure Osmometry Stability constants of some neutral carriers and their bridged isologues in interaction with Li⁺ and Na⁺ are determined by a differential vapour pressure osmometry method in ethanol utilizing Bjerrum formation curves. All ionophores studied induce high Li⁺ selectivity in solvent polymeric membranes.     

Tripodal lipophilic ionophores: synthesis, cation binding and transport through liquid membranes

New C₃-symmetric lipophilic tripodal ionophores, Et(CH₂OCH₂COR)₃; R=NMePh (1), R=NEtPh (2), R=piperidyl (3), have been prepared and their binding abilities for alkali and alkaline earth metal cations evaluated by extraction equilibrium and cation transport through bulk liquid membranes. Experiments show that these ionophores have considerable potential for transporting lithium, sodium and calcium ions relative to potassium and magnesium ions. The cation transport rates by ionophores 1 and 2 decrease in the order Li⁺>Na⁺>Ca²⁺>Ba²⁺>K⁺>Mg²⁺, and the selectivities of Li⁺/K⁺, Na⁺/K⁺ and Ca²⁺/Mg²⁺ are 6.47–7.24, 6.05–6.19 and 9.39–16.13, respectively. The extraction selectivity sequences of the ionophores 1 and 2 are in agreement with the descending order of the cation transport rate, and the complexation constants in chloroform phase were estimated.     

Ion-selective electrodes based on molecular tweezer-type neutral carriers

Potentiometric properties of cholic and deoxycholic acid derivatives substituted with various ion-recognizing moieties, such as dithiocarbamate, bipyridyl, glycolic and malonic diamides, urea and thiourea, and trifluoroacetophenons (TFAP), have been studied using solvent polymeric membranes. The dithiocarbamate and bipyridyl group containing ionophores exhibit high silver ion selectivity. The cholic acid derivatized with glycolic diamides exhibited high calcium selectivity, but its complex formulation constant was 10⁵ times smaller than that of ETH 1001. The reduced calcium binding ability of the glycolic diamide-substituted ionophore was advantageous for eliminating anionic interference. The bi- or tripodal malonic diamide-substituted ionophores exhibited substantially increased magnesium selectivity. Anion-selective ionophores have been designed by substituting urea and thiourea group containing chains to the hydroxyl linkers of chenodeoxycholic acid frames; their selectivity closely followed the sequence of Hoffmeister series, except the unusually large response of the thiourea-substituted ionophore to sulfate. The most successful examples of cholic or deoxycholic acid frame-based ionophores are those functionalized with two carbonate-selective TFAP groups: bipodal TFAP groups behaves like a tweezers for the incoming carbonate, and exhibit analytically interference free and quantitative responses to the carbonate in serum and seawater samples.