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1.
The nuclear properties of99mTc radionuclide are ideal for organ imaging. Study of the technetium transport across supported liquid membranes has been performed to get data for its separation from other elements. Tri-n-octylamine diluted in xylene was used to constitute the liquid membranes, supported in polypropylene microporous films. Stripping on the product solution side was performed with dilute NaOH solutions. The effect of sulphuric acid, nitric acid and hydrochloric acid in the feed on transport of99mTc as TcO
4
–
ions has been studied. The permeability of the given ions determined from kinetic activity data has been found to be in the order of PH2SO4>PHCl>PHNO3. The flux values have been calculated based on this permeability data. The increase in carrier concentration has shown an increase in flux and permeability values to a given optimum concentration. The increase in temperature has been found to reduce the transport of Tc ions. The optimum conditions for transport of99mTc for the given acid concentration have been determined. Mechanism of Tc ion transport has also been provided based on chemical reactions involved at the membrane interfaces and uptake of Tc ions by the membrane. MoO
4
2–
ions do not permeate through membrane under optimum conditions of transport for TcO
4
2–
ions from H2SO4 solution. 相似文献
2.
Q. Zini 《Fresenius' Journal of Analytical Chemistry》1992,344(7-8):322-325
Summary A sensitive spectrofluorimetric method is based on the complexation of Al with the dye Mordant Black 17 or Calcon (CI 15705). The complex solution in n-propyl alcohol (1.5×10–4 mol/l) is mixed (5:20) with 1 mol/l acetic acid — sodium acetate buffer (pH 4.8) and maintained at 40°C for 60 min. The fluorescence intensity is measured at Ex=565 nm, Em=610 nm: The calibration curve for Al was found to be linear in the range 0 to 60 ng×ml–1 with a standard deviation of =1.5 and an Al detection limit of 3 ng×ml–1. The interferences due to more than 40 ions were investigated; the presence of Fe3+, Cr3+, Co2+, Cu2+, Ti4+, VO2+, ZrO2+, WO
4
2–
, MoO
4
2–
, CrO
4
2–
and particularly F–, must be avoided or masked during the determination of Al. The sample of silicon/silicon dioxide was treated with a mixture of conc. HF and HNO3 (2:1), followed by digestion and distillation at 90°C to eliminate the matrix as fluorosilicic acid. A small residue of AlF3 was decomposed with HClO4. In SiO2 anodized layers (25–250 g) the minimum detection of Al was estimated to be 1018 At×cm–3, in monocrystalline silicon (25–250 mg) 1016 At×cm–3. The method can also be employed to determine the presence of Al in the residues by distillation of a small quantity (5–10g) of many solvents or reagent solutions.
Presented at: IX. Congresso Nazionale — Div Chim Anal (S.C.I.) Ferrara 1990 相似文献
3.
The solubility of powellite [CaMoO4(c)] was studied in aqueous Na2MoO4, CaCl2 and Ca(NO3)2 solutions ranging in concentrations from 1×10–4M to 1.0M and over equilibration times extending to 36 days. Our experimental data were interpreted using the aqueous ion-interaction model of Pitzer and coworkers. The Ca2+–MoO
4
2–
ion-interactions were found to be analogous to Ca2+–SO
4
2–
. The use of Ca2+–MoO
4
2–
ion-interactions parameters ((0)=0.2, (1) = 3.1973 and (2)) and a logK
sp
of –7.93 gave excellent predictions of all of the experimental data. Commonion ternary interaction parameters such as MoO
4
2–
–Cl– or MoO
4
2–
–NO
3
–
were not required. 相似文献
4.
S. N. Muddukrishna D. V. S. Narasimnan C. N. Desai 《Journal of Radioanalytical and Nuclear Chemistry》1990,140(1):153-157
A new technique for the separation of99mTc from low specific activity99Mo is reported. A separation based on the principle of precipitation of99Mo as calcium molybdate has been investigated. On precipitating99MoO
4
2–
from alkaline solution as calcium molybdate under controlled conditions, the99mTcO
4
–
is found to remain quantitatively in the supernatant solution with little carry-over of99Mo. This calcium molybdate (99Mo) could be redissolved and reprecipitated at regular intervals, yielding99mTc quantitatively in aqueous neutral solutions. Calcium molybdate precipitates containing up to 1.5 GBq of99Mo and 130–180 mg of molybdenum were prepared and evaluated. The performance in terms of repeated99mTc separation gave yields of 75–93% with acceptable readionuclidic and radiochemical purity. 相似文献
5.
S. C. Gupta B. B. Tak N. K. Mathur C. K. Narang 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):3-8
Polyamino group-containing resins act both as chelating ion exchangers and weakly basic anion exchangers depending upon the species in contact in the solution. In the present work, ion exchangers based on polyamine incorporated polysaccharides (cellulose and galactomannan or guaran) have been used for removal of radioisotopes of185W as WO
4
2–
,99Mo as MoO
4
2–
and125Sb as Sb3+ from their separate aqueous solutions. These chelating anion exchangers have been synthesized by reaction of polysaccharides with epichlorohydrin followed by the respective polyamines as nucleophiles in a strongly alkaline medium. WO
4
2–
and MoO
4
2–
are adsorbed from their aqueous solutions through anion exchange process by chloride form of cellulose-triethylenetetraamine (cellulose-trien), cellulose-tetraethylenepentaamine (cellulose-tetren), guaran-triethylenetetraamine (guar-trien) and guar-tetraethylenepentaamine (guar-tetren) weakly basic anion exchangers. Guar-tetren chelating polymer has been found to be highly selective for125Sb isotopes presumably due to the presence of chelating cis-hydroxy and tetren groups in the galactomannan matrix. 相似文献
6.
Summary The indication of the sulphate precipitation-titration using adsorption-polarized electrodes (APE) has been maximized. Large differences in quality of the two electrode surfaces produce broad signals. Suitable preparation of the electrode leads to less defective surfaces. Sharp signals result when the platinum black is electrodeposited at 1.4 V followed by oxidation under the same conditions. Addition of lead-, copper- and mercury-salts to the plating solution increases the surface of the deposits, whereas deposits containing Fe are smoother and lead to sharp peaks.Adsorption as well as coprecipitation of oxoanions cause interference. SeO
4
2–
and VO
3
–
does not interfere with the determination up to a molar ratio of sulphate to oxoanion of 7.51 and 51 resp., whereas a molar ratio up to 25:1 of CrO
4
2–
, MoO
4
2–
, WO
4
2–
and AsO
3
sulphate can be tolerated. The influence of IOO
4
2–
is negligible. Furthermore, the determination of MoO
4
2–
and WO
4
2–
was found to be possible by titration using APE-indication. 相似文献
7.
O. G. B. Nambiar J. Weinzierl F. Umland 《Fresenius' Journal of Analytical Chemistry》1985,322(3):327-328
Summary A new ion-selective electrode which can be used for the nitrate determination in a concentration range of 10–1 to 10–4 mol/l is described. The polymer ion-exchanger membrane is formed by an epoxy resin, after Nitron nitrate having been introduced serving as an anchor group. The selectivity constants k
t-i have been determined for Cl–, ClO
4
–
, HCO
3
–
, SO
4
2–
, HPO
4
2–
, MoO
4
2–
and WO
4
2–
.
Dedicated to Prof. Dr. H. Monien on the occasion of his 60th birthday 相似文献
Neue ionenselektive Elektrode für die Nitratbestimmung
Zusammenfassung Es wird eine neue ionenselektive Elektrode beschrieben, die für Nitratbestimmungen im Konzentrationsbereich von 10–1 bis 10–4 mol/l verwendet werden kann. Die Ionenaustauschermembran besteht aus Epoxidharz, in das Nitronnitrat als Ankergruppe eingeführt wurde. Die Selektivitätskonstanten K T-I für Cl–, ClO 4 – , HCO 3 – , SO 4 2– , HPO 4 2– , MoO 4 2– und WO 4 2– wurden bestimmt.
Dedicated to Prof. Dr. H. Monien on the occasion of his 60th birthday 相似文献
8.
T. I. Tikhomirova O. V. Krokhin D. B. Dubovik A. V. Ivanov O. A. Shpigun 《Journal of Analytical Chemistry》2002,57(1):18-23
The chromatographic behavior of molybdic heteropoly acids of silicon and phosphorus as ion pairs with tetrabutylammonium bromide was studied by ion-pair high-performance liquid chromatography on the C18reversed phase (UV detection at 310 nm). Heteropoly acids were preconcentrated as ion pairs with tetrabutylammonium bromide to increase the sensitivity of the determination. Optimal conditions were selected for the chromatographic determination of silicon and phosphorus in water in the presence of each other. Detection limits for silicon and phosphorus are (1.1 × 0.3) × 10–3and (6.7 × 1.2) × 10–3g/mL, respectively. Calibration plots are linear in the concentration ranges 0.01–0.1 g/mL (silicon) and 0.02–0.15 g/mL (phosphorus). The procedure was used for the analysis of distilled water. 相似文献
9.
Summary A simple method has been developed to determine the concentration of organic chlorine in waste oil. The determination is based on the conversion of organic chlorine to inorganic chloride by reaction with sodium biphenyl followed by extraction with nitric acid and a mixture of nitric acid and water. The concentration of chloride is determined by direct potentiometry with an ion-selective electrode. The limit of determination amounts to 3·10–5 mol·l–1 chloride ions with a standard deviation of 3.5%. Different samples of waste oil have been analyzed and the results have been compared to those obtained by combustion in a H2/O2 flame followed by potentiometric titration with silver nitrate. 相似文献
10.
Rahila Borissova Abderrachman Debouki Tzanko Nikolov 《Fresenius' Journal of Analytical Chemistry》1993,347(1-2):63-66
Summary Titrimetric methods for a fast determination of phosphates and monofluorophosphates in tooth pastes are described. They are based on the precipitation of PO
4
3–
-ions (directly or after the hydrolysis of PO3F2–-ions) as BiPO4 in nitric acid (pH 0.1–0.5). The end-points are detected visually (back EDTA-titration of the non-bonded Bi3+-ions), or potentiometrically (direct titration of phosphates with bismuth by a specially prepared Bi/Bi2O3-electrode). The titrations are performed without separating the precipitate. An ultrasonic field is applied to accelerate the destruction of the dentifrices. 相似文献
11.
Izak M. Potgieter Stephen S. Basson Andreas Roodt Johann G. Leipoldt 《Transition Metal Chemistry》1988,13(3):209-211
Summary The kinetics of the reaction between [MoO2(CN)4]4– and F– have been studied in the pH range 8 to 11. The results indicated that the diprotonated form, [MoO(OH2)(CN)4]2–, is the only reactive species and that the aqua-ligand is substituted by the F– ion according to the following reaction. The k1 and k–1 values are 8.8(2) M–1 s–1 and 0.6(1)s–1, respectively, at 15°C. A dissociative substitution process is proposed. 相似文献
12.
M. S. Subramanian 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(2):91-97
The present paper describes a novel type of extractant for actinides called bis (dioctylcarbamoylmethyl) sulfoxide which neither contains phosphorus nor entails the addition of tributyl phosphate as phase modifier for extraction. This extractant, abbreviated as CMSO, has been found to be freely soluble in dodecane and to form no third phase even with concentrations of nitric acid as high as 10M. The distribution ratios for the extraction of Am(III), Pu(IV) and U(VI) at trace levels have been found to be 13, 220 and 11, respectively, from 5M nitric acid using 0.2M CMSO in dodecane and those for back-extraction have been found to be 2×10–4, 8×10–3 and 5×10–2 using 0.01M nitric acid, 0.1M oxalic acid and 0.35M sodium carbonate, respectively. Similar distribution ratios were obtained with the recycled extractant. Extraction was found to be very rapid. Eu(III) and Sr(II) were found to be moderately extracted with distribution ratios of 2 and 0.77, respectively, while the extraction of Cs(I) was negligible (KD=0.005). 相似文献
13.
T. Sato 《Journal of Radioanalytical and Nuclear Chemistry》1990,139(1):79-87
Distribution coefficients of fission products in nitric acid for strongly acidic cation exchanger of sulfonic acid type with different cross-linking and structure were measured by a column method. Uptake of cationic fission products increases with resin cross-linking and decreases of nitric acid concentration. The distribution coefficient of the ion, [KdMn+]*, in a given system is expressed as log [KdMn+]*=B·log[KdMn+]+A where [KdMn+] is the distribution coefficient of the ion at 1M nitric acid for 10% crosslinked gel type cation exchanger, while A and B constants. Deviation from the above relation were observed for Y3+ and complex ions of ruthenium upward for macroporous type cation exchanger and downward for highly porous type cation exchanger. Upward deviation of Y3+ for 10% cross-linked gel type cation exchanger increased with concentration of nitric acid. Consequently, elution sequence varied from Y3+–Eu3+–Pm3+–Ce3++ at 1M nitric acid to Eu3+–Pm3+–Y3+–Ce3+ for the same cation exchanger at 2M nitric acid. The same elution sequence, Eu3+–Pm3+–Y3+–Ce3+, was observed for 8% cross-linked gel type cation exchanger and 10% cross-linking macroporous type cation exchanger at 1M nitric acid. 相似文献
14.
P. Ph. Chappuis S. Truffer E. Ianoz P. Lerch 《Journal of Radioanalytical and Nuclear Chemistry》1993,175(2):113-128
The reaction of [99mTcNCl4]– with ethylenediamine-N,N'-diacetic acid (ENDA) has been studied. Starting from [99mTcNCl4]– prepared according to the method of Apparu et al.6, the exchange reaction with ENDA in the presence of stannous tartrate led to the formation of an anionic99mTcN-ENDA complex. The labeling yield was about 90% at pH values of 10.5 and 6.5. In the absence of the reducing agent the formation of99mTcO4
– is reflected in the decrease of the complex yield. The exchange reaction of [99TcNCl4]– with ENDA at pH 6.5 and in the absence of a reducing agent resulted in the formation of the anionic99TcN-ENDA complex and99TcO4
–. The spectrophotometric characteristics (UV-vis. and IR) of the pure complex are similar to those of some tcN2+-complexes with amine ligands. The electrophoretic and chromatographic behaviors of99mTcN- and99TcN-ENDA anions are identical; this proves the formation of the same complex with both radionuclides. 相似文献
15.
T. Yassine 《Journal of Radioanalytical and Nuclear Chemistry》2000,246(3):665-669
Transport of 99mTcO4
– ions across TOPO-kerosene based supported liquid membrane was investigated at different concentrations of phosphoric acid as a feed solution and different concentrations of TOPO in the membrane, where 0.9% NaCl aqueous solution was used as a stripping solution. The flux of TcO4
– ions across this liquid membrane varied with the concentration of both H3PO4 and TOPO. The best permeability coefficient was obtained at concentrations, [H3PO4] = 3 mole·l–1 and [TOPO] = 0.5 mole·l–1 (P = 2.08·10–9 m2·s–1). The results were utilized for the separation of 99mTc from 99Mo, where a selective and effective separation was obtained since no 99Mo transport across this liquid membrane was noticed while a high rate of 99mTc transport took place. 相似文献
16.
F. H. El-Sweify 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):55-59
Chelex-100, in the anionic form has been studied for its ability to perform selective separation and concentration of some metal ions of nuclear importance from mineral acid solutions. The sorption behavior of Zr(IV)–Nb(V), Mo(VI), Tc(VII), Te(IV) and U(VI) from solutions of hydrochloric and sulphuric acids on Chelex-100 has been studied under static and dynamic conditions. Mo(VI) and Tc(VII) have been concentrated on the resin from hydrochloric or sulphuric acid solutions at low acidities probably, as the anions MoO
4
2–
and TcO
4
–
, respectively. Te(IV) has been isolated from hydrochloric acid solutions of normalities 6 in the form of the anionic chloro complex TeCl
6
2–
. Optimum conditions for elution and separation of Mo(VI), Tc(VII), Te(IV) and U(VI) were recommended. 相似文献
17.
N. Ikeda M. Yoshikawa S. Murakami J. Kunika 《Journal of Radioanalytical and Nuclear Chemistry》1988,122(1):27-33
An isotope exchange method for the speciative determination of phosphorus (PO
4
3–
, PO
3
3–
and total P) in natural water samples is proposed by using the exchange system of moly bdophosphate in the aqueous phase and tetraphenylarsonium molybdophosophate in the organic phase. In this exchange system, only PO
4
3–
exchanges and is determined. When the sample water is treated with Br2 water in advance, the amount of PO
4
3–
+PO
3
3–
can be obtained. When the sample is treated with H2SO4 and HNO3, then the amount of total P can be determined. 相似文献
18.
P. K. Tarafder P. Murugan L. Kunkal D. P. S. Rathore 《Journal of Radioanalytical and Nuclear Chemistry》2002,253(1):135-142
A novel procedure for the extraction of uranium has been described. UO2
2+ forms a 1:3 anionic complex with 2,3-dihydroxynaphthalene in the pH range, 4–12. This anionic complex is best extracted into ethyl acetate at pH 11–12 under the influence of a counter cation, cetyltrimethylammonium bromide. This extraction technique has been extended to the separation of uranium from silicate rock matrices for its determination by fluorimetry. Except Co, Cr, and Fe, most elements present in silicate rocks do not interfere. While the interferences of Co and Cr are suppressed by the addition of EDTA, iron is removed by prior extraction at pH 4–5 as its neutral complex with 2,3-dihydroxynaphthalene. The results compare favourably with those obtained from the conventional technique, i.e., extraction of uranium in ethyl acetate from NHO3 medium under the influence of Al(NO3)3
.9H2O as salting out agent. The extraction system under study is capable of separating even ultra-trace amounts of uranium quantitatively from complex matrices of rock samples. Besides, the method is simple, rapid, cost effective and precludes the use of reagents like nitric acid and aluminum nitrate (salting out agent) required in bulk quantities in the conventional system. 相似文献
19.
D. Axente M. Abrudean A. Bâldea 《Journal of Radioanalytical and Nuclear Chemistry》1996,207(1):163-170
The rate of nitrogen isotope exchange between NO and HNO3 has been measured as a function of nitric acid concentration of 1.5–4M·1–1. The exchange rate law is shown to beR=k[HNO3]2[N2O3] and the measured activation energy isE=67.78kJ ·M–1 (16.2 kcal·M–1). It is concluded that N2O3 participates in15N/14N exchange between NO and HNO3 at nitric acid concentrations higher than 1.5M·1–1. 相似文献
20.
N. Buschmann und E. Schumacher 《Fresenius' Journal of Analytical Chemistry》1982,312(4):338-341
Zusammenfassung Die fällungstitrimetrische Bestimmung von Brenzcatechinatochelatanionen des MoO
4
2–
, WO
4
2–
und VO
3
2–/s-
mit R4N+1 wird untersucht. Zur Aufklärung des Indikationsmechanismus werden auch vergleichende Untersuchungen mit substituiertem Brenzcatechin und mit Zusatz aprotischer Lösungsmittel beschrieben.Die Indikation erfolgt durch Oxidation von adsorbiertem Komplex vor dem Endpunkt bzw. von überschüssigem Ligand nach dem Endpunkt. Der Endpunkt selbst wird durch ein Maximum bzw. durch einen Sprung angezeigt. Dieser einfache Mechanismus wird durch verschiedene Adsorptionsgleichgewichte beeinflußt. Alle drei untersuchten Übergangsmetalle lassen sich nach der beschriebenen Methode nachweisempfindlich und genau bestimmen. Eediglich VO
3
–
macht eine Ausnahme, indem es als einfach geladenes Esterchelatanion zur Dimerisierung neigt und die Anodenoberfläche blockiert: Die Eichfunktion verläuft hier schon bei kleinen Konzentrationen in Form einer Sättigungskurve. Die Standardabweichung für die fällungstitrimetrische Bestimmung der zweiwertigen Esterchelatanionen beträgt dagegen bei 0,1 mmol erst etwa 1% rel.
Precipitation titration of esterchelate-anions using tenside cations. Amperometric and voltametric indication
Summary The precipitation-titrimetric determination of catechol-chelate anions of MoO 4 2– , WO 4 2– and VO 3 2–/s- by R4N+ 1 is examined. The mechanism of the amperometric resp. voltametric indication is elucidated by comparative examinations using substituted catechols and adding aprotic solvents to the test solutions.Indication is achieved by oxidation of the adsorbed complex prior to reaching the endpoint and by oxidation of ligand excess after having passed the endpoint. Thus, the indication signal is a maximum (catechol) resp. a break (4-nitrocatechol). This simple mechanism is superimposed by several adsorption equilibria. All transition metals under examination may be determined very sensitively and accurately by the method presented with the exception of VO 3 – which because of the monovalency of its complex tends towards dimerisation and blockage of the electrodes' surfaces. In this case, the calibration plot shows saturation already at a low concentration. In contrast, the divalent esterchelate anions have a linear calibration curve and can be determined down to a level of 5×10–3 mmols. The standard deviation is about 1% rel. at 0.1 mmol.相似文献