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At least 307 records · Page 17Linked to original sources
PubMed2006

Comparison of CID spectra of singly charged polypeptide antibiotic precursor ions obtained by positive-ion vacuum MALDI IT/RTOF and TOF/RTOF, AP-MALDI-IT and ESI-IT mass spectrometry.

Various classes of polypeptide antibiotics, including blocked linear peptides (gramicidin D), side-chain-cyclized peptides (bacitracin, viomycin, capreomycin), side-chain-cyclized depsipeptides (virginiamycin S), real cyclic peptides (tyrocidin, gramcidin S) and side-chain-cyclized lipopeptides (polymyxin B and E, amfomycin), were investigated by low-energy collision induced dissociation (LE-CID) as well as high-energy CID (HE-CID). Ion trap (IT) based instruments with different desorption/ionization techniques such as electrospray ionization (ESI), atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) and vacuum MALDI (vMALDI) as well as a vMALDI-time-of-flight (TOF)/curved field-reflectron instrument fitted with a gas collision cell were used. For optimum comparability of data from different IT instruments, the CID conditions were standardized and only singly charged precursor ions were considered. Additionally, HE-CID data obtained from the TOF-based instrument were acquired and compared with LE-CID data from ITs. Major differences between trap-based and TOF-based CID data are that the latter data set lacks abundant additional loss of small neutrals (e.g. ammonia, water) but contains product ions down to the immonium-ion-type region, thereby allowing the detection of even single amino-acid (even unusual amino acids) substitutions. For several polypeptide antibiotics, mass spectrometric as well as tandem mass spectrometric data are shown and discussed for the first time, and some yet undescribed minor components are also reported. De novo sequencing of unusually linked minor components of (e.g. cyclic) polypeptides is practically impossible without knowledge of the exact structure and fragmentation behavior of the major components. Finally, the described standardized CID condition constitutes a basic prerequisite for creating a searchable, annotated MS(n)-database of bioactive compounds. The applied desorption/ionization techniques showed no significant influence on the type of product ions (neglecting relative abundances of product ions formed) observed, and therefore the type of analyzer connected with the CID process mainly determines the type of fragment ions.

Anti-Bacterial Agents↗
PubMed2004

Synthesis of multi-unit protein hetero-complexes in the gas phase via ion-ion chemistry.

The synthesis of protein hetero-complex ions via ion-ion reactions in the gas phase is demonstrated in a quadrupole ion trap. Bovine cytochrome c cations and bovine ubiquitin anions are used as reactant species in the stepwise construction of complexes containing as many as six protein sub-units. For any set of reactants, a series of competitive and consecutive reactions is possible. The yield of complex ions for any given sequence of reactions is primarily limited by the presence of competitive reactions. Proton transfer represents the most important competitive reaction that adversely affects protein complex synthesis. In the present data, proton transfer takes place most extensively in the first step of complex synthesis, when single protein sub-units are subjected to reaction with one another. Proton transfer is found to be less extensive when one of the reactants is a protein complex. The generation of hexameric hetero-complexes containing two cytochrome c molecules and four ubiquitin molecules is demonstrated with two different synthesis approaches. The first involved the initial reaction of several charge states of cytochrome c and several charges states of ubiquitin. The sequence of reactions in this example illustrates the array of possible competitive and consecutive reactions associated with even a relatively simple set of multiply charged reactants. The second approach involved the initial reaction of the 9(+) charge state of cytochrome c and the 5(-) charge state of ubiquitin. The latter approach highlights the utility of the multi-stage mass spectrometric (MS(n)) capabilities of the ion trap in defining reactant ion identities (i.e. charge states and polarities) so that synthesis reactions can be directed along a particular set of pathways.

Animals↗
PubMed1990

Binding studies of ions with cyclodextrins using ion-selective electrodes.

The use of ion-selective electrodes (ISEs) to study the binding of various organic ions to alpha- and beta-cyclodextrins (CDs) is described. The ISEs respond selectively, directly, and continuously to the activity of the free ion of interest in solution. Binding parameters (intrinsic binding constants and number of binding sites) are calculated with a computer program which performs a nonlinear fit of the Scatchard model to the experimental data (electrode potential versus total ion concentration) of a titration of a CD solution with the ion of interest. Electrodes selective to chloramine-T, naproxenate, p-nitrophenolate, and chlorpromazine ions were used as models. One binding site was found for all cases, with binding constants varying from 0.67 x 10(3) M-1 (naproxenate to beta CD) to 1.27 x 10(4) M-1 (chlorpromazine to beta CD) at 25 degrees C and a CD concentration of 0.010 M. Precision for the estimations of the binding parameters was 2.0-7.5% within run and 8-10% between run (n = 3). Nonspecific binding was observed for CAT: beta CD and CPM: beta CD interactions. The effects of pH, temperature, CD concentration, and ionic strength on the binding are also presented. The overall binding phenomenon is discussed in light of the estimates of the thermodynamic parameters in relation to the size of the guest molecule, the possible mechanism(s) involved, and the forces participating in the interaction of ions with CDs.

Cyclodextrins↗
PubMed2001

Software (MSPECTRA) for automatic interpretation of triacylglycerol molecular mass distribution spectra and collision induced dissociation product ion spectra obtained by ammonia negative ion chemical ionization mass spectrometry.

Rapid analysis of molecular mass distributions of triacylglycerol (TAG) mixtures and regioisomeric structures of selected molecular mass species is possible using ammonia negative ion chemical ionization mass spectrometry utilizing sample introduction by direct exposure probe. However, interpretation of spectra and calculation of results is time consuming, thus lengthening the total analysis time. To facilitate result calculation a software package (MSPECTRA 1.3) was developed and applied to automatic processing of triacylglycerol molecular mass distribution spectra and collision induced dissociation (CID) product ion spectra. The program is capable of identifying triacylglycerol molecular mass species possessing different ACN:DB (acyl carbon number:number of double bonds) ratios on the basis of m/z values of [M - H](-) ions. In addition to such identification the program also corrects spectra for abundances of naturally occurring (13)C isotopes and calculates relative proportions of triacylglycerol molecular species in the analyzed samples. If several replicate spectra are processed simultaneously the program automatically calculates an average and standard deviation of relative proportions of molecular species. In the case of CID spectra the program identifies fatty acid fragment ions [RCO(2)](-) and the corresponding [M - H - RCO(2)H - 100](-) ions, and calculates the relative proportions of ions in both groups. These proportions are then used automatically to calculate the fatty acid combinations comprising the parent triacylglycerol molecule and the regiospecific positions of fatty acids. Processing of several replicate product ion spectra simultaneously produces averaged proportions of regioisomers comprising the parent triacylglycerol molecular species and the standard deviation of the analysis. The performance of the program was tested by analyzing triacylglycerol samples of human milk, human milk substitutes, human chylomicron and cocoa butter, and by comparing results obtained by automated processing of the data with manually calculated results.

Ammonia↗
PubMed2002

Some properties of ion trajectories in the radial plane of an axially symmetric ion trap.

In this article we analyse the trajectories of externally generated ions injected in the radial plane into the ion trap. The shape of the envelope curves for two-dimensional (2D) ion trajectories is determined. Conditions under which these envelope curves can be transformed into circles are found. We show that the amplitude of ion oscillations is a minimum in this case and that this mode corresponds to optimised ion trapping conditions. Also we discuss a ring-shaped ion trap mass spectrometer electrode system which consists of two ring electrodes, and which utilises ion trajectories with circular envelope curves.

Ions↗
PubMed1986

Thyrotropin-releasing hormone stimulation of thyrotropin secretion is suppressed by calcium ion antagonists that block transmembrane influx and intracellular mobilization of calcium ion in human subjects.

To evaluate whether extracellular and intracellular calcium ion may be involved in the regulation of TSH secretion in response to TRH in human subjects, the TSH blood level was determined in normal man before and after administration of two kinds of calcium ion antagonists, nifedipine that blocks transmembrane influx of calcium ion and nicorandil that inhibits mobilization of intracellular calcium ion. Administration of nifedipine and nicorandil significantly decreased the blood level of TSH stimulated by TRH, although calcium ion antagonists did not affect the basal level of TSH. The blood level of neither T4, T3, free T4, free T3, nor reverse T3 was altered by administration of calcium ion antagonists. The present study indicates that cytoplasmic calcium ion derived from the extracellular and intracellular sources plays a pivotal role in the controlling of TRH-stimulated TSH secretion in human subjects.

Adult↗
PubMed1991

Imaging acetylcholine-receptor-induced influx of inorganic ions at single-cell resolution with ion microscopy.

Ion microscopy was used to image neurotransmitter-induced tracer ion flux at single-cell resolution. A mammalian muscle cell line (BC3H1) expressing the nicotinic acetylcholine receptor was exposed to 2 mM CsCl, with and without the acetylcholine analog carbamylcholine. 133Cs+, 12C+, 40Ca+, 39K+, and 23Na+ secondary ion images revealing intracellular distribution of these elements were recorded with a CAMECA IMS-3f ion microscope from freeze-fractured freeze-dried BC3H1 cells. The ion images were digitized directly from the microchannel plate/fluorescent screen detector assembly of the ion microscope using a charge-coupled device imager. Submillimolar concentrations of cesium were easily imaged. Cesium images were normalized to carbon images for a direct comparison of carbamylcholine-exposed and control cells. Carbamylcholine-exposed cells showed significantly higher cesium influx than controls. Within the carbamylcholine-exposed cells, cell-to-cell heterogeneity for cesium influx was observed. Injured cells were identified by their potassium, sodium, and calcium signals and omitted from the quantitative analysis of the ion image data. This method should be useful for identifying cells from various regions of the nervous system containing receptors that control the translocation of monovalent cations, including Cs+. Among these neuronal receptors in the central nervous system are those activated by acetylcholine, glutamate, aspartate, or N-methyl-D-aspartate.

Carbon↗
PubMed1990

Chloride ion increases [3H]dopamine accumulation by synaptic vesicles purified from rat striatum: inhibition by thiocyanate ion.

The effect of chloride ion on the transport of [3H]dopamine into synaptic vesicles purified from rat striatum has been evaluated. The inclusion of 10 mM chloride ion in the incubation medium produced a 100% increase in temperature-sensitive [3H]dopamine uptake into synaptic vesicles from approximately 1800 pmol/mg to 3600 pmol/mg of protein. Half-maximal effects were observed with chloride ion at 4 mM concentration. The anion selectivity of stimulation supports the presence of anion channels within the membranes of dopaminergic storage organelles. Low concentrations of thiocyanate ion (less than 10 mM), 4-acetamido-4'-isothiocyano-2-2'-disulfonic acid stilbene (100 microM), and duramycin (5 micrograms/ml) selectively blocked the chloride ion stimulated accumulation of [3H]dopamine. Higher concentrations of these agents are required to significantly reduce [3H]dopamine uptake in the absence of chloride ion. These results suggest that both components of the proton electrochemical gradient (delta psi and delta pH) are important for dopamine uptake by brain vesicles. This article presents the first demonstration that chloride ion plays a role in the transport of dopamine into vesicles isolated from the CNS.

Animals↗
PubMed1995

Potentiation by calcium ions of [3H]MK-801 binding to an ion channel associated with the N-methyl-D-aspartate receptor complex in rat brain.

In vitro addition of Ca2+ ions was effective in almost doubling binding of [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imi ne (MK-801) before equilibrium to an ion channel associated with an N-methyl-D-aspartate (NMDA)-sensitive subclass of brain excitatory amino acid receptors. The addition of inhibitors for phospholipase (PLase) A2 markedly reduced binding in the absence of added Ca2+ ions, while Ca2+ ions restored the reduction to the level found in the absence of the inhibitors. Pretreatment with PLases A2 and C but not D was effective in potentiating [3H]MK-801 binding in a biphasic manner at a concentration range of 5 mU/ml-10 U/ml. Moreover, PLases A2 and C at low concentrations not only suppressed the abilities of 3 different agonists to potentiate [3H]MK-801 binding before equilibrium, but also reduced that of Ca2+ ions. These results suggest that Ca2+ ions may potentiate [3H]MK-801 binding to the NMDA channel highly permeable to Ca2+ ions through a mechanism common to that underlying potentiation by exogenous PLase A2 and/or C.

2-Amino-5-phosphonovalerate↗
PubMed1993

Tetraethylammonium ions block 5-HT3 receptor-mediated ion current at the agonist recognition site and prevent desensitization in cultured mouse neuroblastoma cells.

Effects of tetraethylammonium ions on 5-hydroxytryptamine3 (5-HT3) receptor-mediated ion current have been studied in whole-cell voltage clamped N1E-115 cells. Inward currents evoked by superfusion with 10 microM 5-HT are rapidly blocked by external tetraethylammonium and the kinetics of the partially blocked inward currents are slowed down. External tetraethylammonium also prevents, but is unable to reverse, agonist-induced desensitization of the 5-HT3 receptor-mediated ion current. Both effects depend on tetraethylammonium concentration and attain half maximum values at 2.6-2.8 mM tetraethylammonium. Tetraethylammonium acts externally, since substituting internal monovalent cations by 107 mM tetraethylammonium fails to block 5-HT3 receptor-mediated ion current. This ion substitution causes a shift in the current reversal potential towards a more positive value, indicating that the receptor-operated ion channel is permeable to tetraethylammonium. An IC50 effect of external tetraethylammonium is reduced to 28% blockade when currents are evoked by 50 microM instead of 10 microM 5-HT, indicating that tetraethylammonium and 5-HT compete for the same site. It is concluded that tetraethylammonium shows low affinity for (part of) the agonist binding site involved in the activation as well as in the desensitization of the receptor-operated ion channel.

Animals↗
PubMed2005

Novel CFCs-substitutes recommended by EPA (hydrofluorocarbon-245fa and hydrofluoroether-7100): ion chemistry in air plasma and reactions with atmospheric ions.

The ion chemistry of the title compounds, a nonafluorobutyl methyl ether and a hydrofluoropropane, is elucidated by a combination of studies using atmospheric pressure ionization mass spectrometry and triple quadrupole mass spectrometry. In the positive ion mode, the hydrofluoroether readily forms an [M - F]+ ion, attributable to hydronium ion induced dehydrofluorination, the product of which can be further hydrated to give a protonated hydrofluoroester. By contrast, the hydrofluoropropane does not react with the hydronium ion but rather gives hydrofluoroalkenylium cations via H atom and F atom abstraction by the dioxygen radical cation. In the negative ion mode, the fluorobutyl methyl ether undergoes dissociative electron capture with O2-*, O2-*(H2O), O3-*, and NO2- to generate the fluorobutoxy anion, which can dissociate by CF2[doublebond]O loss to give the perfluorocarbanion when the precursor ions are internally excited. The hydrofluoropropane reacts readily with common atmospheric anions to form molecular complexes with F-, O2-*, and O3-* and the strongly H-bonded species, O2-*(HF) and F-(HF). Interestingly, isomeric pentafluoropropanes form in the reaction with O2-*, either O2-*(HF) or F-(HF), depending on the specific pattern of the fluoro substitution.

Air↗
PubMed2006

Structures of alpha-type ions formed in the 157 nm photodissociation of singly-charged peptide ions.

One hundred fifty-seven nm photodissociation of singly-charged peptide ions induces the cleavage of alpha-carbon to carbonyl-carbon bonds along the backbone. a(n) + 1 radical ions are observed as the primary photolysis products of peptides with N-terminal arginines in a linear ion trap mass spectrometer. The radical elimination pathways undertaken by the a(n) + 1 radical ions to form more stable even-electron species are studied in hydrogen-deuterium (H/D) exchange experiments. Two types of a(n) ions along with d-type ions are observed as secondary elimination products. The relative abundance of each depends on the C-terminal residue of the radical fragment ion.

Amino Acid Sequence↗
PubMed2006

Sub parts-per-million mass measurement accuracy of intact proteins and product ions achieved using a dual electrospray ionization quadrupole fourier transform ion cyclotron resonance mass spectrometer.

High mass measurement accuracy (MMA) is demonstrated for intact proteins and subsequent collision-induced dissociation product ions using internal calibration. Internal calibration was accomplished using a dual electrospray ionization source coupled with a hybrid quadrupole Fourier transform ion cyclotron resonance (Q-FT-ICR) mass spectrometer. Initially, analyte ions generated via the first electrospray (ESI) emitter are isolated and dissociated in the external quadrupole. This event is followed by a simultaneous switch to the calibrant ion ESI emitter and a disablement of the isolation and activation of the external quadrupole such that a broad m/z range of calibrant ions are accumulated before injecting the analyte/calibrant ion mixture into the ICR cell. Two different internal calibrant solutions were utilized in these studies to evaluate this approach for the top-down characterization of melittin and ubiquitin. While external calibration of protein fragments resulted in absolute MMA greater than 16 ppm, internal standardization significantly improved upon the MMA of both the intact proteins and their products ions which ranged from -2.0 ppm to 1.1 ppm, with an average of -0.9 ppm. This method requires limited modification to ESI-FT-ICR mass spectrometers and is applicable for both positive and negative ionization modes.

Amino Acid Sequence↗
PubMed2006

New polymer-supported ion-complexing agents: design, preparation and metal ion affinities of immobilized ligands.

Polymer-supported reagents are comprised of crosslinked polymer networks that have been modified with ligands capable of selective metal ion complexation. Applications of these polymers are in environmental remediation, ion chromatography, sensor technology, and hydrometallurgy. Bifunctional polymers with diphosphonate/sulfonate ligands have a high selectivity for actinide ions. The distribution coefficient for the uranyl ion from 1 M nitric acid is 70,000, compared to 900 for the monophosphonate/sulfonate polymer and 200 for the sulfonic acid ion-exchange resin. A bifunctional trihexyl/triethylammonium polymer has a high affinity and selectivity for pertechnetate and perchlorate anions from groundwater. In one example, its distribution coefficient for perchlorate ions in the presence of competing anions is 3,300,000, compared to 203,180 for a commercially available anion-exchange resin. Polystyrene modified with N-methyl-D-glucamine ligands is capable of selectively complexing arsenate from groundwater. It complexes 99% of the arsenate present in a solution of 100 mg/L arsenate with 560 mg/L sulfate ions. Its selectivity is retained even in the presence of 400 mg/L phosphate. There is no affinity for arsenate above pH 9, allowing for the polymer to be regenerated with moderate alkali solution. In studies aimed at developing a Hg(II)-selective resin, simple amine resins were found to have a high Hg(II) affinity and that affinity is dependent upon the solution pH and the counterion.

Arsenic↗
PubMed2006

Synthesis and sulfate ion-exchange properties of a hydrotalcite-like compound intercalated by chloride ions.

To reduce the generation of hydrogen sulfide gas from sulfate ions, we synthesized a layered double hydroxide hydrotalcite-like compound intercalated with chloride ions in the interlayer (HT-Cl) using a coprecipitation reaction. The resultant HT-Cl material had a Mg/Al molar ratio of approximately 2, and the molar fraction of the chloride ions on the intercalated anion layer of the HT was 0.90. A higher molar fraction of chloride ions can be inserted into the interlayers of the HT by increasing the initial concentration ratio of chloride ions to aluminum ions [Cl(-)](0)/[Al(3+)](0) in the solution. Approximately 98% of the sulfate ions in the solution were removed within 10 min after adding 1.12 times the stoichiometric quantity of synthesized HT-Cl, which contained a Mg/Al molar ratio of 2 equal to a solution containing a 12 mM calcium sulfate solution.

Air Pollution↗
PubMed2005

Simultaneous analysis of 2-aminopyridine-derivatized neutral and sialylated oligosaccharides from human serum in the negative-ion mode by sonic spray ionization ion trap mass spectrometry.

Neutral and acidic (sialylated) 2-aminopyridine-derivatized (PA) oligosaccharides were analyzed by using reversed-phase high-performance liquid chromatography/ion trap mass spectrometry (RP-HPLC/IT MS) with a sonic spray ionization (SSI) source. Under the RP-HPLC separation using a buffer of 1 mM ammonium acetate (pH4.3) at a flow rate of 0.2 mL/min, both PA-oligosaccharides in the negative-ion mode showed a comparable degree of ionization efficiency, differing from that of the positive-ion mode, which exhibits a wide gap between their ionization efficiencies. In addition, the ion intensities of both PA-oligosaccharides were higher in the negative-ion mode than in the positive-ion mode. These results strongly suggest that the negative-ion mode of SSI-MS is suitable for simultaneous analysis of neutral and acidic (sialylated) oligosaccharides in RP-HPLC/MS. In the present study, RP-HPLC/SSI-IT MS in the negative-ion mode was used in the analysis of PA-oligosaccharides from human serum and its usefulness was investigated. As a result, 32 neutral and sialylated PA-oligosaccharides from human serum were identified with differentiating isomeric oligosaccharides and relatively quantified by a single HPLC/MS run. This method is useful for simple and rapid analysis of the overall distribution of neutral and sialylated oligosaccharides in a complex sample such as serum.

Aminopyridines↗
PubMed1986

Metal ion binding properties of hen ovalbumin and S-ovalbumin: characterization of the metal ion binding site by 31P NMR and water proton relaxation rate enhancements.

In this study, water proton relaxation rate (PRR) enhancements have been used to characterize the binding of metal ions to native ovalbumin, ovalbumin in which phosphate has been enzymatically cleaved from one or both of the two protein phosphoserines, and a heat-stabilized form of the protein (S-ovalbumin). With Scatchard plots constructed from water PRR enhancements, it was found that native ovalbumin and S-ovalbumin had one strong binding site for Mn2+ ion (KD approximately equal to 6.0 X 10(-4) M). Alkaline phosphatase treated ovalbumin, a protein having a single phosphoserine, had one Mn2+ binding site of slightly weaker affinity (KD approximately equal to 8.3 X 10(-4) M), while acid phosphatase treated ovalbumin, a dephosphorylated protein, had two much weaker Mn2+ ion binding sites (KD approximately equal to 1.3 X 10(-3) M). Competitive binding studies on the native protein suggested that Zn2+ ion competes with Mn2+ for the single strong-affinity site (KD approximately equal to 6.1 X 10(-3) M) while Mg2+ and Ca2+ do not. In a second set of experiments, the paramagnetic contribution to the 31P spin-lattice (T1P) and spin-spin (T2P) relaxation times at three separate magnetic field strengths was measured. Correlation times tau c characterizing Mn2+-31P dipolar relaxation were estimated from the ratios of T1P/T2P at a single field and from the ratios of spin-lattice relaxation rates at three different field strengths. The correlation times so obtained, ranging from about 0.7 to 7.7 ns at the three field strengths, were used in calculating distances from the bound Mn2+ ion to the phosphoserines of native ovalbumin, S-ovalbumin, and alkaline phosphatase treated ovalbumins. It was determined that the phosphate of phosphoserine-68 was 5.95 +/- 0.26 and 6.29 +/- 0.18 A from the Mn2+ in the native and alkaline phosphatase treated protein, respectively, and 6.99 +/- 0.30 A away from the Mn2+ in S-ovalbumin. The phosphate of phosphoserine-344 was determined to be 5.31 +/- 0.20 and 5.75 +/- 0.10 A from the Mn2+ ion in native ovalbumin and S-ovalbumin, respectively. The 13C nucleus of [1-13C]galactose enzymatically transferred to the nonreducing end of the ovalbumin oligosaccharide chain was not found to be significantly relaxed by Mn2+ bound to the protein, even at 1:1 stoichiometric ratio of metal:protein. Using this, we estimate the nonreducing terminal of the ovalbumin oligosaccharide to be at least 39 A from the metal ion binding site on the protein.

Animals↗
PubMedDate not supplied

Adsorption of cadmium ion and gallium ion to immobilized metallothionein fusion protein.

A fusion protein made from maltose binding protein (pmal) and human metallothionein (MT) was expressed using E. coli. The purified recombinant protein (pmal-MT) was immobilized on Chitopearl resin, and characteristics of pmal-MT for metal binding were evaluated. As expected from the tertiary structure of metallothionein, the pmal-MT ligand adsorbed 12.1 cadmium molecules per one molecule of the ligand at pH 5.2. The pmal-MT ligand also bound 26.6 gallium molecules per one molecule of the ligand at pH 6.5. Neither cadmium ion nor gallium ion bound to a control protein bovine serum albumin (BSA). Adsorption isotherms for both ions were correlated by Langmuir-type equations. Two types of binding sites have been elucidated on the basis of HSAB (hard and soft acid and base) theory. It was suggested that gallium ion specifically binds to amino acid residues containing oxygen and nitrogen atoms, while cadmium ion binds to specific binding sites formed by multiple cysteine residues. The pmal-MT ligand bound these metals in the concentration range of 0.2-1.0 mM, and the bound metal ions could be eluted under relatively mild conditions (pH 2.0). The pmal-MT Chitopearl resin was stable and could be used repeatedly without loss of binding activity. Thus, this new ligand would be useful for recovery of toxic heavy metals and/or valuable metal ions from various aqueous solutions.

Adsorption↗