Abstract: Compositions comprising a tripeptide having the sequence XC1C2; wherein X is any amino acid such that XC1C2 is capable of binding a metal in a square planar orientation or square pyramidal orientation or both; and wherein C1 and C2 are the same or different; and wherein C1 and C2 individually are chosen from a cysteine and a cysteine-like nonnatural amino acid, as well as metal-XC1C2 complexes and methods for forming such complexes.

Abstract: Methods and assay for the portable colorimetric detection of an antioxidant in a food sample. The method includes the steps of providing a colorimetric reagent, the reagent including a plurality of ceria nanoparticles immobilized to a support, contacting the colorimetric reagent with the food sample, and detecting an optical property of the colorimetric reagent, where a change in the optical property of the colorimetric reagent is associated with the presence of antioxidant in the food sample. The change in the optical property of the colorimetric reagent is dependent upon the concentration of the antioxidant in the food sample.

Abstract: A general methodology to design label-free fluorescent functional nucleic acid sensors using a vacant site approach and an abasic site approach is described. In one example, a method for designing label-free fluorescent functional nucleic acid sensors (e.g., those that include a DNAzyme, aptamer or aptazyme) that have a tunable dynamic range through the introduction of an abasic site (e.g., dSpacer) or a vacant site into the functional nucleic acids. Also provided is a general method for designing label-free fluorescent aptamer sensors based on the regulation of malachite green (MG) fluorescence. A general method for designing label-free fluorescent catalytic and molecular beacons (CAMBs) is also provided. The methods demonstrated here can be used to design many other label-free fluorescent sensors to detect a wide range of analytes. Sensors and methods of using the disclosed sensors are also provided.

Abstract: This invention provides methods of using modified magnetic microspheres to extract target ions from a sample in order to detect their presence in a microfluidic environment. In one or more embodiments, the microspheres are modified with molecules on the surface that allow the target ions in the sample to form complexes with specific ligand molecules on the microsphere surface. In one or more embodiments, the microspheres are modified with molecules that sequester the target ions from the sample, but specific ligand molecules in solution subsequently re-extract the target ions from the microspheres into the solution, where the complexes form independent of the microsphere surface. Once the complexes form, they are exposed to an excitation wavelength light source suitable for exciting the target ion to emit a luminescent signal pattern. Detection of the luminescent signal pattern allows for determination of the presence of the target ions in the sample.

Abstract: According to the present invention, there is provided a method of determining a concentration of uranium including: a) a primary measuring step of measuring luminescence intensity or luminescence attenuation of uranium (VI) of an oxidant added sample obtained by adding an oxidant composition to a detection target sample; b) a secondary measuring step of adding different volumes of standard solution containing uranium (VI) having a predetermined concentration to a plurality of oxidant added samples, respectively, and then measuring luminescence intensity or luminescence attenuation of uranium (VI) contained in each standard solution added sample; and c) a calculating step of calculating a concentration of uranium (VI) contained in the detection target sample by a standard addition method based on the primary and secondary measurements. With the method for determining a concentration of uranium according to the present invention, the concentration of uranium may be further rapidly and accurately analyzed.

Abstract: Disclosed is a compound suitable for use as a fluorescent probe for the detection of uranium. The compound enables the qualitative and quantitative analysis of uranium present in waste samples using less expensive apparatuses. The compound of the present invention has the structure shown by the following formula.

Abstract: A general methodology to design label-free fluorescent functional nucleic acid sensors using a vacant site approach and an abasic site approach is described. In one example, a method for designing label-free fluorescent functional nucleic acid sensors (e.g., those that include a DNAzyme, aptamer or aptazyme) that have a tunable dynamic range through the introduction of an abasic site (e.g., dSpacer) or a vacant site into the functional nucleic acids. Also provided is a general method for designing label-free fluorescent aptamer sensors based on the regulation of malachite green (MG) fluorescence. A general method for designing label-free fluorescent catalytic and molecular beacons (CAMBs) is also provided. The methods demonstrated here can be used to design many other label-free fluorescent sensors to detect a wide range of analytes. Sensors and methods of using the disclosed sensors are also provided.

Abstract: Disclosed is an innovative method for detecting metal ions based on selective plasmonic resonance energy transfer between metal-ligand complexes and a single nanoplasmonic particle as a probe. The selective plasmonic resonance energy transfer occurs if a resonance frequency matching condition between the single nanoplasmonic particle and the metal-ligand complexes is satisfied.

Abstract: Novel chemical compounds, with application in fluorometric analytical methods, for qualitative and quantitative determination of biomolecules. The aim of the invention is to identify and prove the suitability of such compounds. Said aim is achieved with compounds of formula (1) where R1 is an antenna function, R2 is a chelate forming agent, containing a coordinated lanthanide(III)ion, X is —OH or a group with affinity for the biomolecule, bonded to a carboxylate group of the chelate forming agent by means of an amide bond and Y is —H or a group with affinity for the biomolecule, coupled to the antenna function.

Abstract: A sample of unknown bacterial spores is added to a test strip. The sample of unknown bacterial spores is drawn to a first sample region on the test strip by capillary action. Species-specific antibodies are bound to the sample when the unknown bacterial spores match the species-specific antibodies, otherwise the sample is left unbound. DPA is released from the bacterial spores in the bound sample. The terbium ions are combined with the DPA to form a Tb-DPA complex. The combined terbium ions and DPA are excited to generate a luminescence characteristic of the combined terbium ions and DPA to detect the bacterial spores. A live/dead assay is performed by a release of the DPA for live spores and a release of DPA for all spores. The detection concentrations are compared to determine the fraction of live spores.

Abstract: Methods and reagents are disclosed for conducting assays. Embodiments of the present methods and reagents are concerned with a solid support such as, for example, a particle. The support includes a chemiluminescent composition that includes a metal chelate. The present inventors observed that, when such support such as, e.g., particles, were employed in assays for the determination of an analyte, stability of signal output by the chemiluminescent composition associated with the particle was unacceptably reduced as compared to particles including other chemiluminescent compositions. In accordance with embodiments of the present invention, the stability of signal output from such particles is enhanced by including in a medium that contains the particles a sufficient amount of one or more stabilizing agents, which may be a chelating agent and/or a metal chelate such as, for example, the metal chelate that is associated with the particle.

Abstract: Disclosed are methods, materials and systems that can be used to determine qualitatively or quantitatively the level of uranium contamination in water samples. Beneficially, disclosed systems are relatively simple and cost-effective. For example, disclosed systems can be utilized by consumers having little or no training in chemical analysis techniques. Methods generally include a concentration step and a complexation step. Uranium concentration can be carried out according to an extraction chromatographic process and complexation can chemically bind uranium with a detectable substance such that the formed substance is visually detectable. Methods can detect uranium contamination down to levels even below the MCL as established by the EPA.

Abstract: Disclosed are 2-quinoxalinol salen compounds and in particular 2-quinoxalinol salen Schiff-base ligands. The disclosed 2-quinoxalinol salen compounds may be utilized as ligands for forming complexes with cations, and further, the formed complexes may be utilized as catalysts for oxidation reactions. The disclosed 2-quinoxalinol salen compounds also may be conjugated to solid supports and utilized in methods for selective solid-phase extraction or detection of cations.

Abstract: The present invention provides fluorogenic compounds for the detection of target metal ions wherein the compounds exhibit a Stokes shift greater than 50 nm and the detectable signal is modulated by photoinduced electron transfer (PET). The present compounds consist of three functional elements, the ion sensing moiety (chelating moiety), the reporter moiety (fluorophore or fluorescent protein) and spacer or linker between the sensing and reporter moieties of the present compound that allows for PET upon binding of a metal ion and excitation by an appropriate wavelength.

Abstract: The invention is directed to a lanthamide chelate composition having a lanthamide, a charged amidate ligand, and a mono- or bidentate neutrally charged coordination compound, the composition being represented by structure I or structure II wherein Ln3+ designates lanthamide, R1 is alkyl, aryl, or heteroaryl; R2 is alkyl, aminoalkyl, aryl or heteroaryl; M is a neutrally charged monodentate coordination compound, M? is a neutrally charged bidentate coordination compound, a=1 or 2; and wherein M and M? comprise N, S, or O. It extends to the process of making the composition.

Abstract: The invention concerns uranium-chelating peptides as well as their uses for decontaminating soils and water, and for detecting and treating people contaminated by uranium. Said peptides have a helix-loop-helix type structure comprising the sequence of a calmodulin loop including at least one mutation of neutral residues selected from the group consisting of S, T, C, H, Y, N and Q, of one, two or three residues of at least one of the four calmodulin calcium binding sites: site I: residues selected among D20, D22 and D24 residues; site II: residues selected among D56, D58 and N60 residues; site III: residues selected among D93, D95 and N97 residues; site IV: residues selected among D129, D131 and D133 residues; said positions being indicated with reference to the human calmodulin sequence.

Abstract: Proposed is a zirconium crucible used for melting an analytical sample in the pretreatment of the analytical sample, wherein the purity of the zirconium crucible is 99.99 wt % or higher. In light of the recent analytical technology demanded of fast and accurate measurement of high purity materials, the present invention provides a zirconium crucible for melting an analytical sample, a method of preparing such analytical sample, and a method of analysis that enables the analysis of high purity materials by inhibiting the inclusion of impurities from the crucible regardless of difference in the analysts and their skill.

Abstract: A fluorescent ion doped glass (or other fluorescing material) and a method for using the fluorescent ion doped glass to enhance a fluorescence imaging technique are described herein. In one embodiment, the fluorescent ion doped glass (or other fluorescing material) is used as a calibration standard to check the uniformity of an intensity profile of an excitation source. In another embodiment, the fluorescent ion doped glass (or other fluorescing material) is used as an offline calibration standard to normalize a native fluorescence image of one or more test samples (e.g., a protein array). In yet another embodiment, the fluorescent ion doped glass (or other fluorescing material) is used as an online calibration standard to normalize a native fluorescence image of one or more test samples (e.g., a protein array).

Abstract: Terpyridine-substituted compounds, compositions and/or related methods, as can be used to selectively detect a wide range of analytes.

Abstract: A system for warning of corrosion, chemical, or radiological substances. The system comprises painting a surface with a paint or coating that includes an indicator material and monitoring the surface for indications of the corrosion, chemical, or radiological substances.

Abstract: The invention relates to compounds, to the complexes they form with a lanthanide, and to the use of the complexes for fluorescence marking or NMR imaging. The complex consists of an Ln ion and a ligand R2—C(X—R1)(R3)—NR4R5. R1 is a functional group, X is a single bond or a hydrocarbon-based chain consisting of at least one alkylene or alkenylene group optionally comprising at least one hetero atom or an arylene. R2 is an anionic group A2 or a C1-C4 alkylene or alkenylene group bearing at least one such group A2 and optionally comprising at least one hetero atom. R3 is H or a C1-C5 alkylene or alkenylene group optionally containing at least one hetero atom, and optionally bearing at least one anionic group A3. R4 is a substituent with light-absorbing properties that forms chelate rings with Ln. R5 is a substituent that forms chelate rings with Ln.

Abstract: Disclosed are functionalized expanded porphyrins that can be used as spectrometric sensors for high-valent actinide cations. The disclosed functionalized expanded porphyrins have the advantage over unfunctionalized systems in that they can be immobilized via covalent attachment to a solid support comprising an inorganic or organic polymer or other common substrates. Substrates comprising the disclosed functionalized expanded porphyrins are also disclosed. Further, disclosed are methods of making the disclosed compounds (immobilized and free), methods of using them as sensors to detect high valent actinides, devices that comprise the disclosed compounds, and kits.

Abstract: Disclosed is a method for the quantitative analysis of a metal element contained in a resin material, which permits quantitatively analyzing the harmful substance such as lead contained in a resin material, comprising decomposing the resin material within a container having at least the inner surface formed of a glassy carbon in the presence of an aqueous solution of an oxidizing acid, heating the organic residue of the decomposed resin material so as to convert the residue into an ash, and quantitatively measuring the metal element contained in the organic residue converted into the ash.

Abstract: The invention relates to compounds, to the complexes they form with a lanthanide, and to the use of the complexes for fluorescence marking or NMR imaging. The complex consists of an Ln ion and a ligand R2—C(X—R1)(R3)—NR4R5. R1 is a functional group, X is a single bond or a hydrocarbon-based chain consisting of at least one alkylene or alkenylene group optionally comprising at least one hetero atom or an arylene. R2 is an anionic group A2 or a C1-C4 alkylene or alkenylene group bearing at least one such group A2 and optionally comprising at least one hetero atom. R3 is H or a C1-C5 alkylene or alkenylene group optionally containing at least one hetero atom, and optionally bearing at least one anionic group A3. R4 is a substituent with light-absorbing properties that forms chelate rings with Ln. R5 is a substituent that forms chelate rings with Ln.

Abstract: Compositions suitable for use as signal generation components of an immunoassay, and methods for their use. According to one aspect of the invention, the composition includes a carrier having a coating of an aminodextran and a metal chelate incorporated therein. The metal chelate is present in the amount of at least 0.065 ?Mole per gram of carrier, and the aminodextran coating density averaging at least about 45 ?g per milligram of carrier. In another aspect of the invention, carrier is dyed with a complex having the formula: M(L1)x(L2)y, wherein M is a metal selected from the group consisting of europium, terbium, dysprosium, samarium, osmium and ruthenium; L1 is a ligand selected from the group consisting of DPP, TOPO, TPPO; L2 comprises a ligand having the formula wherein R is one or more substituents, each substituent comprising an electron donating group; n=2-10; x=1-2; and y=2-4.

Abstract: This invention provides methods of using ion-detecting microspheres containing an ionphore and a chromoionphore in clinical laboratory instrumentation such as flow cytometry for sample analysis. In one embodiment, the microspheres are contacted with a flowing stream of a sample under conditions that allow the ion-selective ionophores to complex with the ions in the sample, and to cause deprotonation of the chromoionophore. The complexes are then exposed to an excitation wavelength light source suitable for exciting the deprotonated chromoionophore to emit a fluorescence signal pattern. Detection of the fluorescence signal pattern emitted by the deprotonated chromoionophore in microspheres containing the complexes allows for determination of the presence of the target ions in the sample. In one embodiment, lead ion-detecting microspheres are provided that can detect nanomolar levels of lead ions with response times on the order of minutes.

Abstract: The present invention is directed, in part, to fluorescein-based ligands for detection of metal ions, and methods of making and using the same.

Abstract: Wipes, methods and kits useful for testing and/or removal of metal from surfaces (such as, dermal surfaces) are disclosed. Exemplar wipes, including the combination of a three-dimensionally textured absorbent support, a cationic surfactant, and a weak acid, are disclosed. In some examples, the cationic surfactant is isostearamidopropyl morpholine lactate (ISML), and the weak acid is citric acid.

Abstract: Luminescent chemical reagents that include complexes of rare earth metals with ligands such as aromatic heterocyclic nitrogen-containing compounds and semi-aromatic oxygen-containing compounds are used to detect small quantities of complex substances such as pharmaceuticals, metabolites, and microorganisms in complex sample mixtures.

Abstract: Fine particles whose excitation light is not UV light or the like which has negative effects on a subject to be analyzed. The excitation light is emitted stably, and has excellent light emitting efficiency. Also a fluorescent probe including: fine particles containing a rare earth element excited by light having a wavelength in a range of 500 nm to 2000 nm and thereby emit up-conversion emission; and a specific binding substance which binds to the fine particles containing a rare earth element.

Abstract: A method of directed automated analysis of a plurality of analytes of a process solution includes providing a sample of the process solution containing a plurality of the analytes, admixing an enriched isotope spike for each of the plurality of analytes to be analyzed with the process solution sample thereby effecting admixture of the enriched ratio of isotopes with the naturally occurring ratio of each analyte to be analyzed, creating ions from the spikes, introducing the ions into a mass spectrometer for determination of the identity and quantity of each analyte and delivering the information to a microprocessor. If desired, the process solution sample may be diluted and/or subjected to the addition of reagents or standards prior to initiation of the analysis. The ions may be created by an atmospheric pressure ionization interface. The information obtained is processed in a computer which serves to control other portions of the practice of the method.

Abstract: The present invention relates to the preparation of a sample. Preferably, the sample is a sample to be analyzed, for example for ingredient content, etc. Preferred samples include foods, cosmetics, paints, coatings, adhesives, tanning agents, fabrics, chemical compositions, dyestuffs, samples subject to forensic studies, etc. Samples prepared according to the invention method are digested in sulfuric acid, nitric acid, and one or more fluoride salts selected from LiF, NaF, RbF, CsF and KF and then preferably subjected to analysis for metal content, etc, for example using atomic absorption (“AA”) and inductively coupled plasma (“ICP”).

Abstract: A method of analyzing relatively large soil samples for actinides by employing a separation process that includes cerium fluoride precipitation for removing the soil matrix and precipitates plutonium, americium, and curium with cerium and hydrofluoric acid followed by separating these actinides using chromatography cartridges.

Abstract: The present invention provides fluorogenic compounds for the detection of target metal ions wherein the compounds exhibit a Stokes shift greater than 50 nm and the detectable signal is modulated by photoinduced electron transfer (PET). The present compounds consist of three functional elements, the ion sensing moiety (chelating moiety), the reporter moiety (fluorophore or fluorescent protein) and spacer or linker between the sensing and reporter moieties of the present compound that allows for PET upon binding of a metal ion and excitation by an appropriate wavelength.

Abstract: The present invention teaches a marker useful for detection and measurement of free radical damage. Specifically, the invention takes advantage of alterations which occur to the N-terminus of the albumin molecule, a circulating protein in human blood, in the presence of free radicals. These alterations affect the ability of the N-terminus of the albumin molecule to bind metals. Methods for detecting and quantifying this alteration include evaluating and quantifying the cobalt binding capacity of an albumin containing sample, analysis and measurement of the ability of albumin to bind exogenous cobalt, detection and measurement of the presence of copper in a purified albumin sample and use of an immunological assay specific to the altered form of serum albumin which occurs following free radical damage.

Abstract: Methods and systems for the concentration and removal of metal ions from aqueous solutions are described, comprising treating the aqueous solutions with photoswitchable ionophores.

Abstract: The present invention is directed, in part, to sensors for detecting metal ions, and methods of making and using the same.

Abstract: A method for determining the presence or amount of a gadolinium chelate in a biological sample. The method includes contacting a biological sample with a dye selected from arsenazo III or chlorophosphonazo at low pH, and measuring the absorbance of the sample, thereby determining the presence or amount of gadolinium in the sample. A method for determining glomerular filtration (GFR) rate in a mammal. The method includes administering to the mammal an amount of a gadolinium chelate and determining the concentration levels of the chelate in biological samples taken from the animal at plurality of intervals following administration of the chelate. The concentration levels of the chelate are correlated to GFR.

Abstract: A process for synthesizing nanoparticles, in particular metal salt nanoparticles. To the synthesis mixture is added a modifying reagent which binds, by means of a first functional group, to the nanoparticle surface and which carries a second functional group for binding to molecules which are specifically selected in dependence on the subsequent use of the nanoparticles. This dispenses with a postsynthetic, separate, application-specific modification step. A new substance class, the pentaalkyl iminobis(methylenephosphono)carboxylates, are particularly suitable for this purpose.

Abstract: In one embodiment, a method of neutralizing the matrix of an acidic solution including at least one metal using a weak anion exchange resin is provided. The method includes the acts of: activating the weak anion exchange resin with a weakly acidic metal complexing reagent, the weakly acidic metal complexing reagent partially disassociating into protons and metal complexing anions, whereby some functional groups in the weak anion exchange resin are protonated and bind with the metal complexing anions; and neutralizing a sample of the acidic solution with the activated weak anion exchange resin.

Abstract: The present invention provides compositions and methods for detecting, analyzing, and identifying biomolecules. More particularly, the invention provides Element Coded Affinity Tags comprising a metal chelate and a metal ion and methods of using the tags to detect, analyze, and identify biomolecules including polypeptides, nucleic acids, lipids, and polysaccharides.

Abstract: Device and methods for the removal of phospholipids from biological samples are disclosed and described. Removal of phospholipids may be desirable for the analysis of the phospholipids themselves, or to prevent the phospholipids from conflicting with and effectively masking other analytes in the sample for which identification or quantification is sought.

Abstract: This invention provides methods of using ion-detecting microspheres containing an ionphore and a chromoionphore in clinical laboratory instrumentation such as flow cytometry for sample analysis. In one embodiment, the microspheres are contacted with a flowing stream of a sample under conditions that allow the ion-selective ionophores to complex with the ions in the sample, and to cause deprotonation of the chromoionophore. The complexes are then exposed to an excitation wavelength light source suitable for exciting the deprotonated chromoionophore to emit a fluorescence signal pattern. Detection of the fluorescence signal pattern emitted by the deprotonated chromoionophore in microspheres containing the complexes allows for determination of the presence of the target ions in the sample. In one embodiment, lead ion-detecting microspheres are provided that can detect nanomolar levels of lead ions with response times on the order of minutes.

Abstract: Plasticizer-free ion-detecting sensors for detecting a target ion in a sample are provided. The sensor comprises a plasticizer-free copolymer comprised of polymerized units of methacrylate monomers and a polymerizable ion exchanger, wherein the methacrylated monomers have pendent alkyl groups of different length and wherein the functionalized ion-exchanger is grafted into the copolymer through covalent linkages. The ion exchanger comprises a C-derivative of a halogenated closo-dodecacarborane anion having a polymerizable moiety. Sensors of this invention include carrier-based ion-selective electrodes or optodes such as thin film ion-specific optodes, particle-based optodes, or bulk optodes.

Abstract: An analytical apparatus to monitor fluid systems has at least one extraction module having a raw-sample reservoir connected by input fluid conduit to individual ones of said fluid systems, to extract raw samples for analysis from said fluid systems, one or more modification modules comprising additive materials to modify the extracted raw samples prior to analysis, an analytical device to receive at least a portion of said raw samples in an ordered sequence, and to determine concentration of at least one constituent of said sample portion, fluid-handling apparatus for transferring fluid through the analytical apparatus, and a computerized control and management system to manage operations of component modules and devices, and to report analytical results.

Abstract: The invention concerns scintillation proximity assays performed in multiwell plates where a charge coupled device is used to image the wells. Conventional phosphors emit blue light (350–450 nm) which is absorbed by yellow or brown assay components. This problem is addressed by the use of phosphors that emit radiation of longer wavelength (480–900 nm).

Abstract: The present invention provides compositions and methods for detecting, analyzing, and identifying biomolecules. More particularly, the invention provides Element Coded Affinity Tags comprising a metal chelate and a metal ion and methods of using the tags to detect, analyze, and identify biomolecules including polypeptides, nucleic acids, lipids, and polysaccharides.

Abstract: The invention relates to an enhancement solution for an assay technology using lanthanide ions or their chelates as labels and dissociative fluorescence enhancement as a tool for detection, wherein said enhancement solution comprises a ?-diketone of formula I wherein R1 is an aryl, optionally mono- or multi-substituted, and R2 is a straight or branched alkyl chain with 2 to 9 carbon atoms substituted with four or more fluorine atoms. The invention further relates to a bioaffinity assay using lanthanide ions or their chelates as labels and dissociative fluorescence enhancement as a tool for detection comprising the use of said enhancement solution.

Abstract: A plasticizer-free ion detective sensor for detecting a target ion in a sample is provided. The sensor comprises a copolymer of methacrylate monomers with pendant alkyl groups of different length, and an ionophore for detecting the target ion. The copolymer matrix of the present invention may be in a form of membrane or particles. The sensors of the present invention may be Carrier-based ion-selective electrodes (ISEs) or optodes such as thin film ion-specific optodes or particle-based optodes. The ionophore may be a target ionophore selective for a target ion H+, Li+, Na+, K+, Ca2+, or Mg2+. The ion detective sensor of the present invention may further include an ion exchanger such as halogenated carboranes. Also provided is an ion detective sensor comprising halogenated carboranes as ion exchangers. Particularly, trimethylammonium-2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 undecabromocarborane (TMAUBC) is used as ion exchangers.

Abstract: Ion-detecting sensors for detecting a target ion in a sample are provided. The sensor comprises a plasticizer-free copolymer comprised of polymerized units of methacrylate monomers having pendent alkyl groups of different length and a functionalized ionophore of said ion, wherein at least a portion of the functionalized ionophore is grafted into the copolymer through covalent linkages. Sensors may comprise ionophores such as hydrophilic crown ethers or functionalized derivative of 3-oxapentandiaminde-type ionophores. This invention further provides sensors for detecting target ions in a sample, comprising plasticizer-free molecularly imprinted polymers, wherein the polymers comprise polymerized units of methacrylate monomers having pendent alkyl groups of different length and a functionalized ionophore of said ion. In particular, a magnesium ion sensor comprising a functionalized derivative of a 3-oxapentandiaminde-type calcium ion-selective ionophore is provided.