Determination of mineral balances in sheep offered feed with added cadmium and zinc

The optimum conditions for microwave digestion of herbage and faeces to determine mineral concentrations were obtained by varying sample mass, reagent and heating programme, and it was confirmed that the resulting element concentrations were the same as for certified reference material. The effects of feeding cadmium to sheep at a level that is typical of polluted regions (1 mg/kg) for ten days were investigated, as well as the possible amelioration of cadmium effects by adding 30 mg/kg Zn to the diet. Cadmium in the feed increased the cadmium balance and produced several mineral disturbances, in particular a reduction in sodium balance which is typical of renal tubular disorders. Including zinc in the diet as well as cadmium reduced the cadmium balance to a level similar to that of sheep that did not receive cadmium or zinc, which suggests that the zinc status is critical in determining whether cadmium in feed increases the cadmium balance in sheep. Received: 1 August 1997 / Revised: 8 December 1997 / Accepted: 10 December 1997     

粗锌中镉的测定方法研究

采用火焰原子荧光法（FAFS）和电感耦合等离子体质谱法（ICP-MS）测定铅锌矿中的镉. 通过对比研究,两种方法的校准曲线相关系数良好（r>0.999 5）,方法检出限、准确度和精密度均符合质量规范要求. 经过铅锌矿实际样品的比对,两种方法不存在显著性差异. FAFS法比ICP-MS法测定时间短,精密度高,适用于大批量铅锌矿样品的测定.

     

Determination of zinc and cadmium by flow injection analysis and chemiluminescence

Zinc (10–100 ng ml^-1 and cadmium (20–200 ng ml^-1) are successively eluted from an ion-exchange column and determined by their inhibition of the cobalt-catalyzed chemiluminescence generation from luminol.     

Determination of cadmium in zinc ores by thermal neutron absorption analysis

A method has been developed for routine determination of cadmium in zinc ores by thermal neutron absorption analysis, based on the attenuation of a thermal neutron flux passing through a neutron absorbing material. The thermal neutron flux is related to the⁵²V-activity induced in a vanadium detector, surrounded by pellets pressed from a mixture of powdered material with graphite. Besides cadmium, also the major constitutents zinc, iron and sulfur contribute significantly to the total attenuation of the thermal neutron flux. Calibration lines for these elements are worked out. All irradiations are carried out for 200 s in the partially thermalized neutron flux of a 5 Ci²²⁷Ac—Be isotope neutron source. After a decay of 30 s, the⁵²V-activity of the vanadium detector is measured for 400 s with a NaI(T1) scintillation detector. The analysis sequence, including the computation of the results from the counting data, is automated by means of a LSI—11 microprocessor with 12K×16 bit memory. Zinc ores, containing 0.02 to 1.45% cadmium, have been analyzed with a precision ranging from 12.6% to 0.54% relative. As a test for the reliability of the method, two NBS standard reference materials were analyzed in the same way as the zinc ore samples.     

Determination of copper,cadmium and zinc by atomic absorption spectroscopy

A procedure for the direct determination of zinc, cadmium and copper in air and water has been developed. The possible interference effects of numerous anions and cations have been investigated. Few interferences were found, and these were eliminated by the addition of EDTA. The sensitivities found were 2 p.p.b. for cadmium, 8 p.p.b. for copper and 2 p.p.b. for zinc.     

Determination of cadmium in Bentonite clay mineral using a carbon paste electrode

Sodium activated Bentonite, a sodium modified Montmorillonite, was submitted to cadmium sorption from nitrate solutions in order to simulate a cadmium polluted clay mineral. The remaining cadmium concentration in solution was analyzed at equilibrium by means of Differential Pulse Polarography (DPP) in order to calculate the cadmium concentration sorbed by the clay. The cadmium distribution between clay mineral and solution was observed for different concentrations, showing a Freundlich sorption profile. The clay mineral, previously submitted to the cadmium sorption procedure, was included in a carbon paste in order to investigate the cadmium content by voltammetric determination. For cadmium detection in Bentonite, a linear response of the carbon paste electrode (CPE) was observed in the 5 · 10^–5– 1.8 · 10^–4 mol/g range with good reproducibility. Received: 23 July 1998 / Revised: 19 November 1998 / Accepted: 26 November 1998     

Determination of cadmium in Bentonite clay mineral using a carbon paste electrode

Sodium activated Bentonite, a sodium modified Montmorillonite, was submitted to cadmium sorption from nitrate solutions in order to simulate a cadmium polluted clay mineral. The remaining cadmium concentration in solution was analyzed at equilibrium by means of Differential Pulse Polarography (DPP) in order to calculate the cadmium concentration sorbed by the clay. The cadmium distribution between clay mineral and solution was observed for different concentrations, showing a Freundlich sorption profile. The clay mineral, previously submitted to the cadmium sorption procedure, was included in a carbon paste in order to investigate the cadmium content by voltammetric determination. For cadmium detection in Bentonite, a linear response of the carbon paste electrode (CPE) was observed in the 5 · 10^–5– 1.8 · 10^–4 mol/g range with good reproducibility. Received: 23 July 1998 / Revised: 19 November 1998 / Accepted: 26 November 1998     

Determination of arsenic,cadmium and zinc in river water by neutron activation analysis

A concentration apparatus has been developed for the determination of As, Cd and Zn in water by neutron activation. The preconcentration technique used for this purpose is based on the retention of As, Cd and Zn on the Rexyn 201 resin at pH 10. The apparatus used minimizes the manipulations needed for preconcentration and contamination by trace elements present in reagents. Eleven samples of water from rivers in the Montreal region were analyzed and the following concentrations were found (in μg/1): As 0.86–1.95, Cd 0.61–0.98 and Zn 4.6–12.9.     

Extraction separation of cadmium and zinc with tetra-n-butylammonium iodide

Tetra-n-butylammonium iodide (TBAI) forms associations in chloroform and aqueous solutions. A TBAI solution in chloroform extracts hydroiodic acid by addition. From 0.5M hydroiodic acid medium cadmium is quantitatively extracted into a TBAI solution in chloroform. Under these conditions zinc is not extracted. This makes possible the extractive separation of cadmium from zinc in micro-or macroamounts.     

Determination of cadmium and zinc in fertilizer samples by FAAS after solid-phase extraction with freshly precipitated manganese-diethyldithiocarbamate.

Using freshly precipitated manganese-diethyldithiocarbamate (Mn(DDTC)(2)) as a new reagent, a solid phase extraction method (SPE) has been developed for the extraction of Cd(II) and Zn(II) in aqueous fertilizer samples. A sample solution of 300 mL was taken and 0.10 g of freshly precipitated Mn(DDTC)(2) was added. After adding a phosphate buffer solution, the mixture was stirred at 10 min, filtered with a glass filter and washed with deionized water. The solid product containing Mn(DDTC)(2)-Cd(DDTC)(2)-Zn(DDTC)(2) complexes was dissolved in concentrated nitric acid and its volume was made complete up to 10 mL with deionized water. The metal contents of the solution were measured by an atomic-absorption spectrometer.     

Determination of iron in cadmium and cadmium telluride

A procedure is described for the determination of iron in the 10(-6)-10(-4)% range in cadmium and cadmium telluride. Acetylacetone is used for the separation of iron from cadmium, and the iron is determined spectrophotometrically with bathophenanthroline.     

Determination of lead,cadmium, zinc and manganese in copper by anodic stripping voltammetry

Traces of lead, cadmium, zind and manganese in copper and copper compounds are determined, in some cases simultaneously, by anodic stripping voltammetry on a hanging mercury drop electrode. The four metals are separated from the bulk copper(II) by preliminary electrolysis of the copper matrix at a controlled potential on a platinum cathode. The method is applied to commercially available high-purity copper, showing satisfactory sensitivity and accuracy. The determination limits are about 10^-9M for lead, 5·10^-10M for cadmium, 10^-9M for zinc and 10^-8M for manganese in solution ; this corresponds, respectively, to 0.01, 0.002, 0.003 and 0.03 p.p.m. for a 0.5-g sample in a final volume of 25 ml after separation. However, because of blank values, the final determination limits are about 0.1 p.p.m. for lead and 0.3 p.p.m. for zinc.     

Determination of cadmium and zinc in waters by flame atomic absorption spectrometry after cloud-point extraction

Phase separation of nonionic surfactants in aqueous solutions was used to extract cadmium and zinc. After complexation with 6-(4-nitrophenyl)-2,4-diphenyl-3,5-diazabicyclo[3.1.0]hexene-2 (pH 1), cadmium and zinc were quantitatively transferred into the phase rich with the nonionic surfactant octylphenoxypolyethoxyethanol. After the addition of tetrahydrofuran and HCl to the extract, the elements were determined by flame atomic absorption spectrometry.     

Interaction of ampicillin with zinc and cadmium ions in aqueous solutions

In weakly acidic and neutral media, Zn²⁺ and Cd²⁺ ions form 1: 1 chelates with ampicillin in the anionic form; the ligand is coordinated through amino and anionic carboxylate groups.     

Determination of cadmium and bismuth in high-purity zinc metal by inductively coupled plasma mass spectrometry with on-line matrix separation

Traces of cadmium and bismuth in high-purity zinc metal were determined by inductively coupled plasma mass spectrometry (ICP-MS) in combination with flow injection (FI) on-line matrix separation (FI-ICP-MS). The anion-exchange separation method of the potassium iodide (KI) system was applied to the separation of the analytes from the matrix zinc. The analytes, cadmium and bismuth, were adsorbed on the anion-exchange (BIORAD AG1-X8) mini-column (1.0 mm i.d.× 100 mm bed length), while the matrix zinc can be completely removed from the anion-exchange resin. The analytes were eluted by 2 mol/l HNO₃ and directly introduced into the ICP-MS. The detection limits (D.L.) obtained by using a single injection (350 l) were 0.81 and 0.075 ngg^-1 for cadmium and bismuth, respectively. In the case of multi-injection concentration onto the anion-exchange mini-column (five injections 350 l each), the detection limits could be improved to 0.16 and 0.014 ngg^-1 for cadmium and bismuth, respectively. The reproducibilities of the single injection and the multi-injection method were satisfactory with a relative standard deviation of less than 5% (at the 10 and 1 ngml^-1 level for the single injection and the multi-injection method, respectively). The method was successfully applied to the determination of trace impurities in four samples of high-purity zinc metal (7 nines grade) and three standard reference materials of high-purity unalloyed zinc samples (from NIST).     

Determination of cadmium and bismuth in high-purity zinc metal by inductively coupled plasma mass spectrometry with on-line matrix separation

Traces of cadmium and bismuth in high-purity zinc metal were determined by inductively coupled plasma mass spectrometry (ICP-MS) in combination with flow injection (FI) on-line matrix separation (FI-ICP-MS). The anion-exchange separation method of the potassium iodide (KI) system was applied to the separation of the analytes from the matrix zinc. The analytes, cadmium and bismuth, were adsorbed on the anion-exchange (BIO. RAD AG1-X8) mini-column (1.0 mm i.d.x 100 mm bed length), while the matrix zinc can be completely removed from the anion-exchange resin. The analytes were eluted by 2 mol/l HNO(3) and directly introduced into the ICP-MS. The detection limits (D.L.) obtained by using a single injection (350 microl) were 0.81 and 0.075 ng g(-1) for cadmium and bismuth, respectively. In the case of multi-injection concentration onto the anion-exchange mini-column (five injections 350 microl each), the detection limits could be improved to 0.16 and 0.014 ng g(-1) for cadmium and bismuth, respectively. The reproducibilities of the single injection and the multi-injection method were satisfactory with a relative standard deviation of less than 5% (at the 10 and 1 ng ml(-1) level for the single injection and the multi-injection method, respectively). The method was successfully applied to the determination of trace impurities in four samples of high-purity zinc metal (7 nines grade) and three standard reference materials of high-purity unalloyed zinc samples (from NIST).     

Thermal studies of zinc and cadmium halide complexes with N-tert-alkylacrylamides

The thermal properties of complexes of N-tert-butylacrylamide and N-tert-amylacrylamide with ZnCl₂, ZnBr₂, CdCl₂ and CdBr₂ have been studied in air and in argon by TG and DTA. The decomposition proceeds in two steps with evolution of simple, low molecular weight gaseous products. The use of various heating rates revealed an additional exothermic DTA peak for complexes with zinc and cadmium chlorides corresponding to a solid state polymerization reaction which was confirmed by IR spectral analysis. This effect was not observed for corresponding complexes of zinc and cadmium bromides, which show much lower thermal stability.

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Zusammenfassung Die thermischen Eigenschaften der Komplexe von N-Tertbutylacrylamid und N-Tertamylacrylamid mit ZnCl₂, ZnBr₂, CdCl₂ und CdBr₂ wurden in Luft und in Argon durch TG und DTA studiert. Die Zersetzung verläuft in zwei Stufen unter Entwicklung einfacher gasförmiger Produkte niedriges Molekulargewichts. Der Einsatz verschiedener Aufheizgeschwindigkeiten zeigte für Komplexe mit Zink- und Cadmiumchloriden einen zusätzlichen DTA Peak, der Festphasen-Polymerisationsreaktion entsprechend, welche durch IR-Spektralanalyse bestätigt wurde. Dieser Effekt wurde bei den entsprechenden Komplexen der Zink- und Cadmiumbromide, welche eine viel geringere Thermostabilität besitzen, nicht beobachtet.

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Résumé On a étudié, par TG et ATD, dans l'air et l'argon, les propriétés thermiques des complexes du N-tertbutyl-acrylamide et du N-tétramylacrylamide avec ZnCl₂, ZnBr₂, CdCl₂ et CdBr₂. La décomposition s'effectue en deux étapes, avec dégagement de produits gazeux simples de faible poids moléculaire. L'application de différentes vitesses de chauffage a révélé, pour les complexes des chlorures de zinc et de cadmium, un pic exothermique additionnel en ATD qui correspond à la réaction de polymérisation dans l'état solide et qui a été confirmé par spectrométrie infrarouge. On n'a pas observé cet effet dans le cas des complexes correspondants des bromures de zinc et cadmium dont la stabilité thermique est bien plus faible.

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N- - N- ZnCl₂, ZnBr₂, CdCl₂ CdBr₂. , . . , . , .