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1.
Inductively coupled plasma-mass spectrometry (ICP-MS) incorporated with an on-line preconcentration system was used to determine trace amounts of ten metals including Ni, Cu, Zn, Rh, Ag, Cd, In, Au, Tl, and Pb in aqueous solutions and seawater. These metals, which formed the complexes, were retained in a sorbent microcolumn, followed by elution with methanol through a desolvation unit, which was capable of removing 83% of methanol. The limits of detection for these elements were determined simultaneously to be in the range from 3 to 20 ng/L. 相似文献
2.
The preconcentration and separation of palladium and iridium from base metals is studied with cellulose (Cellex T) and styrene-divinylbenzene (Varion AT 400) anion exchangers. In spite of lower capacity of Cellex T to chloride complexes of Pd and Ir, it allowed to get a higher preconcentration factor. Yields of 92–99% are achieved for Pd and 96–97% for Ir from the solutions containing great excess of base and heavy metals. Graphite furnace atomic absorption spectrometry is used for the final measurements. The procedure has been applied to the determination of palladium in natural samples. 相似文献
3.
Polyethylene powder has been shown to function effectively as an adsorbent for the preconcentration of complexing agents and their metal complexes. The adsorbed trace compound can easily be eluted from the polyethylene by use of polar organic solvents and subsequently be determined by AAS or spectrophotometry. In this paper, the adsorptivity of chrome azurol S and rhodamine B and their complexes with aluminium, beryllium and thallium (as [Tl Br4]–) on polyethylene was investigated. The influence of the pH and the effect of the saline concentration of the solution were studied. From the preconcentration of aluminium and beryllium with chrome azurol S, enrichment factors up to 10 and 20, respectively, could be achieved. For thallium with rhodamine B the factor was 50. With this analytical procedure, recoveries of 92–110%, 94–103% and 96–104% with relative standard deviations of 3.4–5.4%, 2.6–5.3 and 1.6–7.2% for aluminium, beryllium and thallium respectively, were achieved. The method was used for the preconcentration of trace amounts of the metals from tap water, dialysis solutions and solid salts. 相似文献
4.
V. Mikulaj P. Rajec A. Švec N. H. Cuong V. N. Ahn 《Journal of Radioanalytical and Nuclear Chemistry》1986,101(1):67-69
A continuous extraction device for preconcentration of metals with light phase internal recycle has been developed. This system was used for preconcentration of cobalt and uranium from 20–30 dm3 samples with 10.8 dm3/hours feed rate. The emulsion membranes were created of surfactants and LIX 64 N (for cobalt) or di-2ethylhexyl-phosphoric acid (for uranium) as a carrier to control stability and permeability for long time periods. The results from continuous extraction of cobalt and uranium using the device constructed have shown the possibility to reach 100–200-fold preconcentration of metals with high yield (min. 92%). 相似文献
5.
V. M. Ostrovskaya E. A. Reshetnyak N. A. Nikitina A. V. Panteleimonov Yu. V. Kholin 《Journal of Analytical Chemistry》2004,59(10):995-1001
A test procedure is proposed for determining total metals (Cd, Co, Cu, Fe, Hg, Ni, and Zn) using irregular 1-(2-carboxyphenyl)-5-(4-methyl-6-methoxypyrimidine-2-yl)formazan-6-cellulose as an indicator paper. Regions of unreliable color reactions were determined for each of the metals and total metals present in equal concentrations. Statistical processing showed that the Weibull distribution function best describes the experimental results in the unreliable reaction regions. Unreliable reaction was observed in the range (3.6–4.4) × 10–3 mg/L for the test procedure with preconcentration and in the range 1.7–3.4 mg/L for the procedure without preconcentration; the detection limits are 4.4 × 10–3 and 3.4 mg/L, respectively. A synergetic effect of the component mixture was observed in determining total metals. The visual, reflectometric, and atomic absorption determination of total Co, Cu, Fe, Ni, and Zn in natural and tap water was studied; it was shown that the results of test determination agree well with the data of other methods. 相似文献
6.
Valfredo Azevedo Lemos Douglas Gonalves da Silva Anaildes Lago de Carvalho Dbora de Andrade Santana Geisiane dos Santos Novaes Adenilde Souza dos Passos 《Microchemical Journal》2006,84(1-2):14-21
A new chelating sorbent has been developed using Amberlite XAD-2 resin anchored with pyrocatechol through –N=C– group. This sorbent, characterised by elemental analysis and infrared (IR) spectra, was used as packing for the minicolumn in an on-line system preconcentration system for cadmium, cobalt, copper and nickel determination. Metal ions were sorbed in the minicolumn, from which it could be eluted directly to the nebulizer–burner system of the flame atomic absorption spectrometer (FAAS). Elution of all metals from minicolumn can be made with 0.50 mol L− 1 HCl or HNO3. The enrichment factors obtained were 16 (Cd), 24 (Co), 15 (Cu) and 19 (Ni), for 60 s preconcentration time, and 39 (Cd), 69 (Co), 36 (Cu) and 41 (Ni), if used 180 s preconcentration time. Under the optimum conditions, the proposed procedure allowed the determination of cadmium, cobalt, copper and nickel with detection limits of 0.31, 0.32, 0.39 and 1.64 μg L− 1, respectively, when used preconcentration periods of 180 s. The accuracy of the developed procedure was sufficient and evaluated by the analysis of the certified reference materials NIST 1515 apple leaves and NIST 1570a spinach leaves. The method was applied to the analysis of food samples (spinach, black tea and rice flour). 相似文献
7.
FEI Yan-qun LUO Gui-min FENG Guo-dong CHEN Huan-wen FEI Qiang HUAN Yan-fu JIN Qin-han . Key Laboratory for Molecular Enzymology Engineering of Ministry of Education 《高等学校化学研究》2008,24(5):546-549
This article focuses on iodine determination by microwave plasma torch atomic emission spectrometry (MPT-AES) coupled with online preconcentration vapor generation method. A new desolvation device, multistrand Nafion dryer, was used as the substitute for condenser desolvation system. Some experimental conditions, such as preconcentration time, acidity of sample solution, rinsing solution acidity and dynamic linear range were investigated and optimized. The new desolvation system eliminates the problem of decreasing emission intensity of I(I) 206.238 nm line with the increase of working time on a conventional condenser desolvation system, thus greatly improving the reproducibility. 相似文献
8.
V. A. Popova A. Yu. Tsivadze I. V. Podgornaya E. N. Pyatova A. V. Kopytin L. V. Eganova 《Russian Chemical Bulletin》1990,39(9):1911-1914
Novel podands with 4-antipyryliminomethine groups on benzenes and various numbers of ethers are prepared. According to UV spectroscopy, these compounds form complexes with alkali, alkaline earth, and transition metals. Extraction of metal picrates demonstrated that the podands selectively form extractable complexes with these salts. A lead-selective electrode with an electrode function 22–24 mV/pPb is based on 1,8-bis[2-(4-antipyryliminomethine)phenoxy]-3,6-dioxaoctane. This enables 1·10–6–1·10–2 M Pb to be determined in the pH range 3.5–5.5. The electrode is highly selective for Pb in the presence of alkali and alkaline earth metals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2099–2102, September, 1990. 相似文献
9.
A method is proposed for calculation of the catalytic activity of the complexes of transition metals. An effective Hamiltonian describing the behavior of the reagents in the presence of the catalyst is formulated, and a catalytic activity index tan2 is introduced. The isomerization of quadricyclane to norbornadiene is considered. It is shown that the index in the case of the catalytically active low-spin complex CoTPP is two orders of magnitude larger than in the case of the catalytically inactive high-spin complex MnTPP and the analogous Fe(III)TPP and MnPc complexes.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 4, pp. 398–406, July–August, 1988. 相似文献
10.
I. E. Uflyand I. A. Il'chenko A. G. Starikov V. N. Sheinker A. D. Pomogailo 《Russian Chemical Bulletin》1990,39(2):388-391
Syntheses are reported for a series of metal- chelate monomers derived from metha-croylacetophenone. IR, UV, and magnetochemical data indicate an octahedral configuration of the chelate unit. The metal- ligand bond in the complexes of transition metals with methacroylacetophenone is significantly covalent in nature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 451–453, February, 1990. 相似文献
11.
Grigory I. Tsysin Irina V. Mikhura Andrew A. Formanovsky Yury A. Zolotov 《Mikrochimica acta》1991,105(1-3):53-60
New cellulose fibrous sorbents, containing a diethylenetriamine tetraacetate groups, are proposed for the preconcentration of heavy metals. Quantitative extraction of heavy metals from river and sea water is achieved in a wide pH range (3–8) at a high solution flow rate (up to 100–150 volumes of sorbent per minute). Quantitative desorption of metals is achieved with a very small volume of the acid. 相似文献
12.
Conclusions A new complex of Cr(V) with an antimony-containing ligand was obtained and studied by the EPR method. The additional hyperfine structure from the121Sb and123Sb isotopes was observed for the first time in solutions of complexes of the transition metals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 731–732, March, 1974. 相似文献
13.
V. V. Krivykh O. V. Gusev M. G. Peterleitner L. I. Denisovich M. I. Rybinskaya 《Russian Chemical Bulletin》1986,35(6):1308-1311
Conclusions A method was developed for the synthesis of cationic olefinic and dienic complexes of transition metals entailing the simultaneous reaction of an acid and unsaturated organic substrate with a metal carbonyl compound containing a metal-metal bond.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1440–1443, June, 1986. 相似文献
14.
G. I. Malofeeva O. M. Petrukhin B. Ya. Spivakov L. S. Rozhkova 《Journal of Analytical Chemistry》2001,56(3):238-242
A procedure was proposed for the preconcentration of Sr, Cs, Pb, Co, Bi, and Ce beta radionuclides by solid-phase extraction as ion-pair complexes in the system dicyclohexyl-18-crown-6–sodium dodecyl sulfonate. 相似文献
15.
I. I. Grinval'd B. V. Lokshin N. K. Rudnevskii V. P. Mar'in 《Russian Chemical Bulletin》1988,37(10):2068-2070
Conclusions CO complexes with the cyclopentadienyl and arene complexes of transition metals are formed at 80–90 and 14–16 K on a cold substrate by direct synthesis. The structures of the complexes depend on experimental conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2298–2301, October, 1988. 相似文献
16.
H. C. Budnikov N. A. Ulakhovich V. N. Maystrenko E. P. Medyantseva 《Fresenius' Journal of Analytical Chemistry》1989,335(1):81-85
Summary The main types of electrochemical reactions of complexes in organic and mixed solvents are considered. Fast electrochemical reactions (k
s=n×10–2 cm · s–1) were used to reduce the minimal concentrations (c
min) in a.c. voltammetry. The role of pre- and post-chemical reactions in the formation of the analytical signal in extraction voltammetry is elucidated. The principles of the influence of the special structure of the complexes on their redox properties are determined using complexes of the transition metals with phosphorus dithioacids and bidentate heterocyclic amines. The features of the electrooxidation and electroreduction of inert complexes of the platinum metals with heterocyclic dithioacids and organic sulphides in nonaqueous media are discussed. The products of the electrochemical reaction of these compounds in protic media catalyze the hydrogen evolution on the mercury electrode. Kinetic data of the chelate formation are used for developing highly selective methods for the determination of the platinum metals with c
min=2×10–9–5×10–8 mol/l.
Elektrochemische Reaktionen von Komplexen mit S-haltigen Liganden相似文献
17.
This paper generalizes data on the methods of synthesizing the cubane chalcogenide complexes of group IV–VI transition metals. The regularities of their structures, the physicochemical properties and reactivities (reactions of the ligand substitution and redox transformations) are discussed in detail. 相似文献
18.
D. Pollmann F. Leis G. Tlg P. Tschpel J.A.C. Broekaert 《Spectrochimica Acta Part B: Atomic Spectroscopy》1994,49(12-14)
The use of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of trace elements in Al2O3 powders is reported. Special interest is given to a preconcentration of the trace elements by on-line coupling of chromatography to ICP-MS. This is based on the complexation of Co, Cu, Cr, Fe, Ga, Mn, Ni, V and Zn with hexamethylene-dithiocarbamate (HMDC), their preconcentration on a C18 RP column by reversed phase liquid chromatography and their elution with CH3OH-H2O mixtures. A direct coupling of the HPLC system to the ICP-MS has been realized by high pressure pneumatic nebulization using desolvation. With the Chromatographie method developed, removal of the AI by at least 99% was achieved. For the trace elements V, Fe, Ni, Co, Cu and Ga, high and reproducible recoveries (ranging from 96–99%) were reached. The method developed has been shown to considerably enhance the power of detection as compared with direct procedures, namely down to 0.02–0.16 (
for V and Fe, respectively. The possibilities of the method are shown by the determinations of V, Mn, Fe, Ni, Co, Cu, Zn and Ga at the μg/g level in A12O3 powders. The accuracy of the method at the 0.06 to 9.0
level for Co and Fe, respectively, is demonstrated by a comparison with results of independent methods from the literature. 相似文献
19.
V. V. Strelets 《Theoretical and Experimental Chemistry》1996,32(2):57-66
The main principles of the redox activation of the 18-electron complexes of transition metals with conversion of the complexes into 17- or 19-electron radical-ions, which exhibit substantially higher reactivity, are discussed. It was shown that electrochemical initiation of the isomerization of complexes with polydentate ligands, accompanied by change in the position of coordination of the metal, is possible in the case of the sandwich and semisandwich -complexes of transition metals with aromatic polycondensed ligands.Chernogolovka Institute of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 32, No. 2, pp. 69–79, March–April, 1996. Original article submitted November 13, 1995. 相似文献
20.
Frank Hißner Jürgen Mattusch G. Werner 《Fresenius' Journal of Analytical Chemistry》1996,354(5-6):718-721
The determination of heavy metals in concentrations less than 10-6 mol/L by ion chromatography with conductivity detection requires a preconcentration step. Therefore, a special electrochemical equipment and method was developed for the on-line preconcentration of the divalent metals Ni, Co, Zn and Cd and their subsequent ion chromatographic determination. The loop of the injection valve of an ion chromatograph was replaced by an electrochemical flow-through-cell with a gold working electrode, a platinum auxiliary electrode and a silver/silver sulphate reference electrode. The preconcentration step consists of the deposition of the reduced metals on the electrode surface during a continuous pumping of the sample solution through the cell. After switching of the mobile phase through the cell, the analytes are injected after their reoxidation directly into the mobile phase. A new preconcentration step is simultaneously possible during the actual chromatographic run. An effective separation of the analytes from the matrix is also possible with the proposed system. A maximum of metal ion accumulation was obtained after 120 min in the galvanostatic mode on a gold tube electrode. The detection limits for Co(II), Ni(II), Zn(II) and Cd(II) were improved by a factor of 7.7, 10.4, 11.2, 14.0, respectively, and were in the 0.1 mol/L concentration range with a RSD of 2–6%. The accumulation of metal ions was disturbed in the presence of Cr(III). 相似文献