Simultaneous determination of Al,V, Mn and Cu from neutron-activated saline matrices by precipitation with poly-5-vinyl-8-hydroxyquinoline

Neutron Activation Analysis is a sensitive technique for the determination of more than seventy elements at the trace concentrations. The NAA analysis of biological and environmental matrices suffers from interferences caused by the presence of high concentrations of activated salts in these matrices. The high gamma-ray activities of these activated salts mask the low gamma-ray activities of short half-lived isotopes (e.g.,⁶⁶Cu,⁵⁶Mn,²⁸Al and⁵²V) necessitating the rapid separation of trace metals from high concentrations of salts. Poly-5-vinyl-8-hydroxyquinoline has been used to develop a new method to rapidly and quantitatively precipitate aluminum, copper, vanadium and manganese from neutron-activated biological and environmental matrices.     

镉基体中微量锌的富集与分离研究

提出了一种用于富集分离镉基体中的微量锌的分离体系,研究了从镉基体中富集分离微量锌的可行性——采用二安替比林甲烷(DAM)作为络合剂,与硫氰酸铵、锌在盐酸介质中形成三元离子缔合物,用三氯甲烷作为萃取剂,最后用氨水作为反萃剂将有机相中的锌洗脱出来与镉分离。试验发现,当15%的硫氰酸铵用量为1.5mL,DAM的用量为1.5mL,加入20mL4mol/L的盐酸时,用20mL的三氯甲烷萃取两次,10mL1:3的氨水反萃两次,锌的回收率达到95%以上,相对误差小于0.5%。     

Concentration of trace metals from sea-water by complexation with 8-hydroxyquinoline and adsorption on C(18)-bonded silica gel

A reversed-phase liquid chromatographic technique based on a combination of multielement chelation by 8-hydroxyquinoline with subsequent adsorption on C(18)-bonded silica gel is described for the concentration of Cd, Zn, Cu, Ni, Co, Mn and Fe from sea-water. Enrichment factors of 50-100 are readily obtained following elution of the absorbate with methanol to provide a matrix-free concentrate suitable for graphite-furnace atomic-absorption analysis. Quantitative recovery of these elements from near-shore samples of sea-water is demonstrated and the accuracy and precision of the technique are discussed.     

Determination of trace metals in seawater by graphite furnace atomic absorption spectrometry with preconcentration on silica-immobilized 8-hydroxyquinoline in a flow-system

Summary A flow-system utilizing a miniature column packed with silica-immobilized 8-hydroxyquinoline (I-8-HOQ) was used for the preconcentration of Cd, Pb, Zn, Cu, Fe, Mn, Ni, and Co from seawater prior to their determination by graphite furnace atomic absorption spectrometry (GFAAS). Enrichment factors sufficient to permit the analysis of an open ocean seawater reference material using 50 ml sample volumes (100 ml for Co determinations) were obtained. Recoveries of the above elements from seawater averaged 93% (range 87–97%) with absolute blanks ranging between 0.04 ng (Ni) and 4.0 ng (Fe). Estimated detection limits for these elements vary from 0.2 ng l^–1 (Co) to 40 ng l^–1 (Fe) based on a 50 ml sample volume (100 ml for Co).

---

Bestimmung von Spurenmetallen in Meereswasser durch Graphitofen-AAS mit Anreicherung an Kieselgel-immobilisiertem 8-Hydroxychinolin in einem Durchflu\system

     

Ionic imprinted polymer for nickel recognition by using the bi-functionalized 5-vinyl-8-hydroxyquinoline as a monomer: Application as a new solid phase extraction support

A new ionic imprinted polymer (IIP) for Ni(II) recognition/pre-concentration was prepared via precipitation polymerization using 2-(diethylamino) ethyl methacrylate (DEM) and divinylbenzene (DVB) as a crosslinking agent in the presence of nickel(II) and 5-vynil-8-hydroxyquinoline (5-VHQ) as a bi-functionalized ligand. An important increase on the selectivity of the synthesised IIP for nickel(II) ions was obtained when comparing to the use of 8-hydroxyquinoline (8-HQ) as a ligand. The synthesised IIP was used as a new support for solid phase extraction (SPE) of nickel(II) from seawater before inductively coupled plasma optical emission spectrometry (ICP-OES) detection. Variables affecting the SPE process, such as pH, load and elution flow rates, and concentration and volume of the eluting solution, were fully evaluated. The optimised procedure consists of a sample loading (100 mL of seawater at a pH of 9.0 ± 0.1) through IIP-SPE cartridges containing 300 mg of the synthesised IIP at a flow rate of 3.0 mL min^{− 1}. Elution was performed by passing 2.5 mL of 2.0 M nitric acid at a flow rate of 1.5 mL min^{− 1}, which gave a pre-concentration factor of 40. The limit of detection (LOD) of the method was 0.26 µg L^{− 1}, while the relative standard deviation (RSD) for eleven replicated measurements was 3%. Accuracy of the method was assessed by analyzing SLEW-3 (estuarine water) and TM-23.3 (lake water) certified reference materials. In addition to the selectivity of the synthesised material for nickel(II) ions against other transition metal ions and major alkaline and alkaline-earth metals (Na⁺, K⁺, Mg²⁺ and Ca²⁺) in seawater, it can be stated that the salt matrix is efficiently removed by using the proposed IIP-SPE procedure.     

The separation by thin-layer chromatography of trace metals as their tetraphenylporphyrin chelates.

The tetraphenylporphyrin chelates of iron, cobalt, manganese, nickel, zinc, copper, rhodium lead, cadmium and mercury were prepared and their chromatographic behaviour investigated using four different adsorbents and eleven different solvent systems. Mixtures of lead, cadmium and mercury chelates exhibited isographic behaviour in all conditions; mixtures of the other metal chelates were adequately resolved on silica (MN Polygram Sil SHR) by the solvent system light petroleum (b.p. 80-100 degrees)-toluene-acetic acid-water (66:33:85:15, v/v, upper phase). The intense colours of the chelates permit their visual detection at levels of about 10(-10) moles; using the integrated ion-current mass spectrometric procedure, as little as 10(-14) moles of metal could be detected and assessed.     

Preconcentration of trace metals on Amberlite XAD-4 resin coated with dithiocarbamates and determination by inductively coupled plasma-atomic emission spectrometry in saline matrices

Preconcentration of Cd(II), Cu(II), Mn(II), Ni(II), Pb(II) and Zn(II) in saline matrices on Amberlite XAD-4 resins coated with ammonium pyrrolidine dithiocarbamate (APDC) and piperidine dithiocarbamate (pipDTC) and subsequent determination by inductively coupled plasma atomic emission spectrometry were studied. Parameters such as effect of pH, effect of HNO(3) concentration on elution of metals from resin were studied. The results show that Amberlite XAD-4 coated with APDC was more efficient in the recovery of metal ions compared with Amberlite XAD-4 coated with pipDTC, in the concentration range of 0.1-200 mug l(-1), for 1 g of Amberlite XAD-4 coated resin. The detection limits for Cd(II), Cu(II), Mn(II), Ni(II), Pb(II), Zn(II) are 0.1, 0.4, 0.3, 0.4, 0.6, 0.5 mug l(-1), respectively, for resin coated with APDC and 0.7, 1.0, 0.8, 0.9, 1.7 and 1.2 mug l(-1) for resin coated with pipDTC. The effect of diverse ions on the determination of aforesaid metals was studied. The method was applied for the determination of trace metal ions in artificial sea water and natural water samples. The results were compared with extraction AAS method.     

Analytical evaluation of a cup-horn sonoreactor used for ultrasound-assisted extraction of trace metals from troublesome matrices

In this work, a sample preparation method based on ultrasound-assisted extraction of trace metals from a variety of biological and environmental matrices using a cup-horn sonoreactor is described. Diluted acids (HNO₃, HCl and HF) and oxidants (H₂O₂) were tried for extraction, the extracts being directly analyzed by electrothermal-atomic absorption spectrometry. The cup-horn sonoreactor combines the advantages of probe and bath sonicators, allowing a variety of conditions to be used for metal extraction from troublesome matrices. This system facilitates the use of HF to destroy the silicate lattice, application of simultaneous treatments of up to six samples and short treatment times. Quantitative metal recoveries are achieved from different matrices (animal and vegetal tissues, soil, sediment, fly ash, sewage sludge) under a set of extraction conditions ranging from the use of 3 min sonication time and 3% volume/volume HNO₃ for some animal tissues to 40 min sonication time along with 5% volume/volume HNO₃ + 20% volume/volume HF for sediment. Vegetal matter required the use of 5% volume/volume HNO₃ + 5% volume/volume HF for extraction of some elements.     

Complexation of transition metals with 8-hydroxyquinoline chemically immobilized on the surface of a silica gel-polyaniline composite

The complex-forming properties of a silica gel-polyaniline composite with 8-hydroxyquinoline covalently immobilized by the Mannich reaction with respect to Pb(II), Cd(II), Cu(II), Ni(II), Co(II), Al(III), Fe(III), and Mo(VI) ions were studied. The resulting adsorbent had a high sorption capacity and satisfactory kinetic characteristics, which allowed us to use it for the separation or preconcentration of transition metal ions. Data on the composition and structure of the test metal complexes with 8-hydroxyquinoline immobilized on the composite surface were obtained from an analysis of electronic diffuse reflectance spectra and corresponding adsorption isotherms.     

Improved immobilization of 8-hydroxyquinoline on polyacrylonitrile fiber and application of the material to the determination of trace metals in seawater by inductively coupled plasma mass spectrometry

A modified synthetic method has been developed for immobilization of 8-hydroxyquinoline on polyacrylonitrile fiber. The synthetic conditions, e.g. reagent concentration, reaction temperature and time, were optimized. The features of the newly-modified fiber are higher exchange capacity compared with most other materials containing immobilized 8-hydroxyquinoline, better mechanic characteristics, high stability at both high and low pH, and ease of synthesis. This modified fiber can concentrate and separate trace metals from matrices with higher concentrations of alkali and alkaline earth elements. To validate the characteristics of the modified fiber, trace metals Ag, Be, Cd, Co, Cu, Mn, Ni, Pb, and Zn in the certified reference materials river water (SLRS-4) and seawater (CASS-4, NASS-5, SLEW-3) were preconcentrated before determination by inductively coupled plasma mass spectrometry. Good agreement was obtained between the data obtained by this method and the certified values.     

Direct analysis of solid samples by atomic absorption spectrometry, following preconcentration of trace elements from seawater with 8-hydroxyquinoline

Summary 8-Hydroxyquinoline (8-HOQ) was used for the preconcentration of Cd, Cu, Mn, Pb and Zn from seawater prior to their determination by graphite furnace atomic absorption spectrometry using an inner miniature cup for solid sampling technique. The metal ions in seawater were precipitated quantitatively in the pH range 7–8.5 with 8-HOQ alone. The precipitate thus formed was directly analysed by an atomic absorption spectrometer equipped with a specially deviced graphite furnace and miniature cup. The present method was confirmed to be highly reliable for analysis of seawater. Detection limits (3_b) for Cd(II), Cu(II), Mn(II), Pb(II) and Zn(II) are 1.4, 10, 5, 10, and 6 ng l^–1, respectively, for the analysis of a 400-ml portion of seawater samples. Corresponding precision of 6–14% is typical for determination 5-fold above the detection limits.

---

Direkte Analyse von Feststoffproben durch AAS nach Anreicherung von Spurenelementen aus Meerwasser mit 8-Hydroxychinolin

     

氧化锆微球担体-8-羟基喹啉鳌合固定相的合成及其在痕量金属分析中的应用

以氧化锆微球为担体,通过mannich反应得到在氧化锆微球上键合8-羟基喹啉的痕量金属富集分离固定相,并对该固定相的键合金属离子能力进行了研究。以合成的氧化锆微球键合8-羟基喹啉金属鳌合固定相用作微柱流动注射(FIA)在线分离、富集和电感耦合等离子体质谱(ICP-MS)分析流程中的固定相,对大洋海水中的痕量铅和镉进行了在线分析,得到了较满意的结果。     

Trace metals species in sea-water-I: removal of trace metals from sea-water by a chelating resin

A significant fraction of the copper, lead, cadmium and zinc in sea-water exists in a form which is not retained by a chelating resin (Chelex-100) or extracted by ammonium pyrrolidinedithiocarbamate. Anodic stripping voltammetric results suggest that the major part of the unavailable trace metal is adsorbed on, or occluded in, organic or inorganic colloidal particles. An ionic equilibria computer program was used to predict the effect of various complexing agents on trace metal species in sea-water. Citric acid and amino-acids, with the exception of l-cysteine, were shown to be unimportant as complexing agents, and the ability of an EDTA-like ligand to complex Cu, Pb, Cd and Zn is controlled entirely by the concentrations of the ligand and of "labile" Fe(III) and Cr(III) in sea-water, since these two ions together will react quantitatively with EDTA. l-Cysteine, if present in sea-water, would also complex the trace metals.     

Solid phase extraction of trace amounts of uranium(VI) from water samples using 8-hydroxyquinoline immobilized on surfactant-coated alumina

A simple and reliable method has been developed for the determination of uranium(VI). The method is based on the separation and preconcentration of uranium(VI) using a column packed with 8-hydroxyquinoline immobilized on surfactant coated alumina prior to its spectrophotometry determination with Arsenazo III. The effect of pH, sample flow rate and volume, elution conditions, and foreign ions on the sorption of uranium(VI) has been investigated. A preconcentration factor of 200 was achieved by passing 1000 mL of sample through the column. The relative standard deviation for 10 replicate analyses at the 100 ng/mL level of uranium(VI) was 2.1% and the detection limit was 0.12 ng/mL. The method was successfully applied to the determination of uranium in natural water samples. The accuracy was assessed through recovery experiments and the analysis of a certified reference material.     

Solid phase extraction of trace amounts of uranium(VI) from water samples using 8-hydroxyquinoline immobilized on surfactant-coated alumina

A simple and reliable method has been developed for the determination of uranium(VI). The method is based on the separation and preconcentration of uranium(VI) using a column packed with 8-hydroxyquinoline immobilized on surfactant coated alumina prior to its spectrophotometric determination with arsenazo III. The effect of pH, sample flow rate and volume, elution conditions, and foreign ions on the sorption of uranium(VI) has been investigated. A preconcentration factor of 200 was achieved by passing 1000 mL of sample through the column. The relative standard deviation for 10 replicate analyses at the 100 ng/mL level of uranium(VI) was 2.1% and the detection limit was 0.12 ng/mL. The method was success-fully applied to the determination of uranium in natural water samples. The accuracy was assessed through recovery experiments and the analysis of a certified reference material.     

Studies on derivatives of 8-hydroxyquinoline (oxine). the sensitivity and selectivity of 5-nitroso-oxine and 2-methyl-5-nitroso-oxine towards the group IIIB metals

2-Methyl-5-nitroso-8-hydroxyquinoline (2-methyl-5-nitroso-oxine), hitherto undescribed, has been prepared. The sensitivity and selectivity of this oxine derivative, together with 5-nitroso oxine, and 2-methyl-oxine towards aluminium, yttrium, gallium, indium and thallium(III) have been investigated. A gradation in selectivity is found. With oxine, precipitation occurs with all the above metals under the conditions of the test. With 2-methyl-oxine, precipitation occurs with all metals with the exception of aluminium. With 5-nitroso-oxine, no precipitation occurs with aluminium, yttrium, gallium and indium, and with 2-methyl-5-mtroso-oxine, no precipitation occurs with any metal in Group III B. A possible explanation for this behaviour is advanced.     

Application of radioisotopes in column chromatography on substituted celluloses. part V. : The separation of arsenic from copper and other metals

The Chromatographic behaviour of arsenic and copper was studied with radio-isotopes on natural cellulose, cellobiose and seven substituted celluloses in ethyl ether. Arsenic was not adsorbed; copper was retained and eluted quantitatively. For preparative purposes, one gram of arsenic trioxide was purified from nanograms of copper on natural and diethylaminoethyl celluloses. The possibility of purifying arsenic from several other metals, and gold and mercury from copper is indicated.