Preparation of Chelating Cellulose Filters and Their Application to the Separation and Enrichment of Trace Elements

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磷酸钛离子交换薄层色谱分离无机离子(英文)

The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous,organic and mixed mobile phases.The separation of one ion from several other ions and also ternary and binary separations have been developed.Some important analytical separations are reported.The effect of pH of the mobile phase on retention factor(Rf)values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied.This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationary phase in thin layer chromatography.     

纤维素金属螯合物及其质谱分析在研究血清蛋白质与多肽中的应用

用纤维素做固相支持物,通过碱处理、环氧活化、偶联螯合剂、固定金属离子等方法制成纤维素金属螯合物,并用合成的纤维素金属螯合物处理健康人血清,然后通过基质辅助激光解吸电离飞行时间质谱仪(MALDI-TOF-MS)检测蛋白质和多肽以确定其分离效果。确定了最佳的合成方法、螯合剂、金属离子和缓冲体系。再利用普通的纤维素制成了性能优良的纤维素金属螯合物,它能较好地分离血清中的蛋白质和多肽。     

The efficiency of cellix-p for the preconcentration of lead and other trace metals from waters

The cheating ion-exchanger Cellex-P, a cellulose phosphate ester, is shown to be effective for the preconcentration of Cu, Ni, Mn, Cd, Zn and Pb from water. The pH of the sample is not critical within the approximate range 5–8. The collected ions can be eluted efficiently in 10–25 ml of 1 M nitric acid from 2–16.5-cm columns of resin. Common salts present in natural waters do not interfere. Cellex-P is used for the preconcentration and determination of the metal ions in potable water by graphite-furnace atomic absorption spectrometry.     

Preparation and properties of a new chelating resin containing 1-nitroso-2-naphthol as the functional group

A macroreticular polystyrene-based chelating ion-exchanger containing 1-nitroso-2-naphthol as the functional group has been synthesized. The exchange-capacity of the resin for a number of metal ions such as copper(II), iron(III), cobalt(II), nickel(II), palladium(II) and uranium(VI) as a function of pH has been determined. The sorption and elution characteristics for palladium(II) and uranium(VI) have been thoroughly examined with a view to utilizing the resin for separation and concentration of uranium and palladium. Uranium(VI) has been separated from a mixture of ten other metal ions by sorption on the chelating resin and selective elution with 0.5M sodium carbonate. Palladium(II) has been separated from various metal ions by selective sorption on the resin in 1M hydrochloric acid medium.     

Iminodiacetic acid functionalised organopolymer monoliths: application to the separation of metal cations by capillary high-performance chelation ion chromatography

Lauryl methacrylate-co-ethylene dimethacrylate monoliths were polymerised within fused silica capillaries and subsequently photo-grafted with varying amounts of glycidyl methacrylate (GMA). The grafted monoliths were then further modified with iminodiacetic acid (IDA), resulting in a range of chelating ion-exchange monoliths of increasing capacity. The IDA functional groups were attached via ring opening of the epoxy group on the poly(GMA) structure. Increasing the amount of attached poly(GMA), via photo-grafting with increasing concentrations of GMA, from 15 to 35 %, resulted in a proportional and controlled increase in the complexation capacity of the chelating monoliths. Scanning capacitively coupled contactless conductivity detection (sC⁴D) was used to characterise and verify homogenous distribution of the chelating ligand along the length of the capillaries non-invasively. Chelation ion chromatographic separations of selected transition and heavy metals were carried out, with retention factor data proportional to the concentration of grafted poly(GMA). Average peak efficiencies of close to 5,000 N/m were achieved, with the isocratic separation of Na, Mg(II), Mn(II), Co(II), Cd(II) and Zn(II) possible on a 250-mm-long monolith. Multiple monolithic columns produced to the same recipes gave RSD data for retention factors of <15 % (averaged for several metal ions). The monolithic chelating ion-exchanger was applied to the separation of alkaline earth and transition metal ions spiked in natural and potable waters.     

The electrochemically controlled sorption of d - metal cations by ion exchangers based on titanium phosphate

A study of the sorption of d-metal ions by titanium phosphate on a platinum electrode shows that the potential of the platinum electrode significantly influences the uptake of cations by the ion-exchanger. Cathodic polarization leads to a significant increase of the sorption whereas anodic polarization is accompanied by desorption. Therefore it is possible to perform cycles of sorption and desorption simply by switching the potential. The results obtained can be explained by the fact that the layer of titanium phosphate acts as a phase which extracts protons or hydroxide ions. The electrochemical generation of hydroxide ions at negative potentials can, especially at less acidic pH, lead to the formation of metal hydroxides in the ion-exchanger phase. This interference is less important at a lower solution pH. Received: 5 March 1997 / Accepted: 3 April 1998     

Synthesis,characterization and adsorption behaviour of TX-100 based Sn(IV) phosphate,a new hybrid ion exchanger

A new hybrid ion exchanger, Triton X-100 based tin(IV) phosphate (TX-100SnP) has been synthesized and characterized by ion exchange and physico-chemical methods such as ion exchange capacity, elution and concentration behaviour, IR, X-ray, TG/DTA and elemental analysis. Its adsorption behaviour has also been studied for some alkaline earths and heavy metal ions in different acidic media. It has been found generally more selective for metal ions as compared to tin(IV) phosphate prepared earlier. For Pb(II), Hg(II) and Fe(III) its selectivity has been found to be exceptionally good. On this basis, some binary separations have been performed involving these metal ions. Thermal studies show a high thermal stability of the material. It retains 54.54% of its i.e.c. at 200°C and 27.27% at 300°C.     

Elimination of phosphate interference in flame photometric determination of strontium and barium

The interference of phosphate in the flame emission of calcium, strontium and barium was studied. The emission intensity decreases proportionally to the amount of interfering anion up to a maximum depression for equimolar amounts of phosphate to metal. A thermostable phosphate is formed before the cation enters the flame. Appropriate addition of lanthanum restores the three alkaline earth lines to their intensities in absence of phosphate, the lanthanum displacing, the alkaline earths from their phosphates before the hot region of the flame is reached.     

Conversion techniques in flow injection analysis: Determination of Sulphide by Precipitation with Cadmium Ions and Detection by Atomic Absorption Spectrometry

A flow-injection system is described for on-line conversion of a soluble species to an insoluble compound by means of a tag-material which subsequently can be determined. This approach is used for the determination of sulphide by flame atomic absorption spectrometry, cadmium(II) ions being used as the precipitating tag-reagent. Excess of cadmium(II) is collected on a chelating ion-exchanger and later eluted. The detection limit for sulphide was 10 μg l^?1 and the sampling rate was 100 h^?1. Typical relative standard deviation was 1.2%. Of the potential interferences tested, only phosphate had any effect.     

Preconcentration of Uranium in Seawater with Heterocyclic Azo Dyes Supported on Silica Gel

Abstract

The chelating adsorbents, heterocyclic azo dyes supported on silica gel, were prepared and their adsorption behaviors of metal ions were investigated. The 1-(2-pyridylazo)-2-naphthol(PAN)-SG and 2-(2-thiazolylazo)-p-cresol(TAC)-SG show greater affinity for UO₂(II) and ZrO(II), compared with the other metal ions like Cu, Cd, Fe and alkaline earths. Trace uranyl can be quantitatively retained on the column of the gels at neutral pH region and flow-rate 3–4 ml/min. The uranyl retained is easily eluted from the column bed with a mixture of acetone and nitric acid(9:1 v/v) and determined by spectrophotometry using Arsenazo-III. Matrix components in seawater do not interfere and the spiked recovery of uranyl in artificial seawater was found to be average 98.6 %, with the relative standard deviation of 1.08 %. Both gels were applied to the determination of uranium in seawater with satisfactory results.     

The effect of metal ions on thermal oxidative degradation of cotton cellulose ammonium phosphate

The thermal oxidative degradation of cellulose, and of cellulose ammonium phosphate and its metal complexes products were studied by thermal analysis, infrared spectroscopy and elemental analysis. The temperature of decomposition was lower for metal complexes of cellulose ammonium phosphate than those samples untreated by metal ions and the values of char yield were greater for treated cellulose than those untreated. This indicates the metal ions can catalyze the reaction of degradation and form more char. This revised version was published online in August 2006 with corrections to the Cover Date.     

新型鳌合纤维素富集原子吸收测定痕量的铅、镉、铜和镍

本文利用自制的新型吡咯烷二硫代甲酸铵螯合纤维素（CC－APDC），经过最佳条件选择，在同一水样中同时富集和洗脱了铅、镉、铜、和镍。实验结果表明，CC－APDC用于痕量元素的分离富集具有交换速度、易于洗脱、富集倍数大、选择性好等优点。样品使用效果令人满意。     

Catalytic actions of alkaline salts in reactions between 1,2,3,4-butanetetracarboxylic acid and cellulose: I. Anhydride formation

1,2,3,4-Butanetetracarboxylic acid (BTCA) reacts with cellulose in two steps: anhydride formation of adjacent carboxyl groups in BTCA and esterification of anhydride with cellulose, which are generally catalyzed by alkaline salts including sodium hypophosphite. The role of the salts in the reactions has been unclear. As an effort in fully understanding the catalytic effects of the salts, reaction mechanisms of alkaline metal ions and acid anions of the salts were investigated in details in the reactions. In this research, functions of alkaline metal ions on the formation of anhydride were studied. Results indicated that the existence of lithium, sodium or potassium promoted the formation of anhydride, and potassium ion was the most efficient one among these three ions. Besides, the reactions of a BTCA molecule with cellulose undergo a step-by-step process, i.e. formation of one anhydride and esterification of the anhydride with cellulose, and then formation of another anhydride and esterification of it to establish cross-linking by the BTCA.     

Automatic ion-exchange chromatograph for analysis of alkali and alkaline earth metal mixtures

A new automatic chromatograph for ultramicro determination of alkali and alkaline earth metals has been developed. It combines a high-sensitivity hydrogen flame-ionization detector with ion-exchange chromatography. Zirconium phosphate was chosen as ion-exchanger.     

Solid phase extraction studies on cellulose based chelating resin for separation,pre-concentration and estimation of Cu2+and Ni2+

Chelating resins based on biopolymers, specifically cellulose, offers a green analytical method for determination of metal ions at trace levels present in various samples. It offers a fast, accurate and simple method for separation and pre-concentration of metal ions at low concentrations, prior to their determination by instrumental method. Cellulose based chelating resin (CELL-GLY) has been synthesised by immobilising glycine on it. CELL-GLY was used for the determination of trace amounts of Cu²⁺ and Ni²⁺ from aqueous solutions before their determination by FAAS. The preparation of CELL-GLY involves simple steps, based on natural and easily available biopolymer cellulose, which makes its use as chelating resin is a green method. The Cu²⁺ and Ni²⁺ can be quantitatively recovered from the CELL-GLY in the pH range 4.8–6.9 and 6.9-7.8 respectively with a recovery of more than 95% for each of these metal ions. Recovery of these metal ions using CELL-GLY was quantitative up to 35 °C. The detection limits for copper and nickel by FAAS were 1.20 ppb and 1.40 ppb, respectively. The method was successfully employed for the determination of trace amounts of Cu²⁺ and Ni²⁺ in various samples.     

Separation and concentration of some platinum metal ions with a new chelating resin containing thiosemicarbazide as functional group

A new chelating ion-exchange resin containing thiosemicarbazide as functional group and based on macroreticular polystyrene-divinylbenzene (8%) has been prepared. Its sorption characteristics for palladium(II), platinum(IV), rhodium(III), ruthenium(III) and iridium(III) have been studied. These platinum metal ions can be quantitatively separated by sorption on this chelating resin and selective elution. The resin is highly stable in acid and alkaline solution.     

Sorption investigation on the removal of metal ions from aqueous solutions using chelating terpolymer resin

A novel chelating terpolymer resin has been synthesized from anthranilic acid, phenylhydrazine, and formaldehyde by condensation in glacial acetic acid. The structure of the chelating resin was clearly elucidated by use of a variety of spectral techniques, for example FTIR, and ¹H and ¹³C NMR spectroscopy. The average molecular weight of the terpolymer resin was determined by gel-permeation chromatography. The empirical formula and empirical weight of the resin were determined by elemental analysis. The physicochemical properties of the terpolymer resin were determined. Scanning electron microscopy was used to establish the surface features of the chelating resin. The ion-exchange behaviour of the resin for specific metal ions, viz. Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, and Pb²⁺, was evaluated by a batch equilibrium method. The study was extended to three variations: evaluation of metal ion uptake in the presence of different electrolytes at different concentrations; evaluation of metal ion uptake at different pH; and evaluation of metal ion uptake at different times. Further, the reusability of the resin was also determined to assess the efficiency of the resin after a few cycles of sorption. From the results it was observed that the resin acts as an effective chelating ion-exchanger.     

Preconcentration of Rare Earth Elements with 8-Hydroxyquinoline-5-sulfonic Acid Chelated Cellulose Filter Prior to Determination by Inductively Coupled Plasma Atomic Emission Spectrometry

ICP- AEShasbecome a widely used technique formulti- elemental major,minorand traceanalyses.However,many elements such as REEsare often presentin real samples atconcen-trations too low to be accurately determined by conventional ICP,especially in biological andenvironmental samples.Moreover the spectral interferences from matrix elementsoften inter-fere with trace REEsdetermination.To determine trace and ultra- trace REEsin complex ma-trices,the separation of the matrix components and th…     

Flow-through chloroquine sensor and its applications in pharmaceutical analysis.

Poly (vinyl chloride) membrane electrodes that responded selectively towards the antimalarial drug chloroquine are described. The electrodes were based on the use of the lipophilic potassium tetrakis(4-chlorophenyl)borate as ion-exchanger and bis(2-ethylhexyl)adipate (BEHA), or trioctylphosphate (TOP) or dioctylphenylphosphonate (DOPP) as plasticizing solvent mediator. All electrodes produced good quality characteristics such as Nernstian- and rapid responses, and are minimally interfered with by the alkali and alkaline earth metal ions tested. The membranes were next applied to a flow-through device, enabling it to function as flow-injection analysis (FIA) detector. The performance of the sensor after undergoing the FIA optimization was further evaluated for its selectivity characteristics and lifetime. Results for the determination of chloroquine in synthetic samples that contained common tablet excipients such as glucose, starch, and cellulose, and other foreign species such as cations, citric acid or lactic acid were generally satisfactory. The sensor was also successfully used for the determination of the active ingredients in mock tablets, synthetic fluids and biological fluids. The sensor was applied for the determination of active ingredients and the dissolution profile of commercial tablets was also established.