Zinc In Biological Materials Research Articles

Primary Reference Procedure for Measuring the Mass Fraction and Molar Concentration of Copper and Zinc in Biological Materials by Isotope Dilution Mass Spectrometry

Primary Reference Procedure for Measuring the Mass Fraction and Molar Concentration of Copper and Zinc in Biological Materials by Isotope Dilution Mass Spectrometry

Optimizing detector geometry for trace element mapping by X-ray fluorescence.

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.

Microwave Assisted Digestion Method for the Determination of Cadmium, Copper, Lead, and Zinc in Biological Materials

AbstractAnodic stripping voltammetry is useful instrumental method for trace element determination in biological materials. It is however extremely demanding to the quality of the sample preparation process. The high‐pressure microwave assisted digestion seems to meet its requirements. The differential pulse anodic stripping voltammetry technique was used for determination of cadmium, copper, lead and zinc in certified reference materials both of plant and of animal origin to prove the analytical properties of such sample preparation method. The found concentrations have been in satisfactory agreement with the certified values. The elaborated digestion procedure is greatly universal and has required accuracy and precision.

Utility of formazans and cetylpyridinium chloride in rapid spectrophotometric determination of zinc in biological materials and pharmaceutical formulations

A facile, rapid and sensitive spectrophotometric method for the determination of zinc is performed, based on complexation reaction between the metal ion and 1,5-diphenyl-3-acetylformazan ( I) 1-( o-carboxyphenyl)-3-acetyl-5-acetylformazan ( II), 1-( o-carboxyphenyl)-3-acetyl-5-phenylformazan ( III), and 1-( o-carboxyphenyl)-3-acetyl-5-m-tolylformazan ( IV) in the presence of cationic surfactant cetylpyridinium chloride (CPC). The important analytical parameters and their effects on the reported system are investigated. Zinc reacts with the reagents ( I– IV) and CPC in the ratio 1:1:2 (metal:reagent:CPC) in the pH range 8.5, 7.5, 5.5 and 6.5 to form a ternary complex with an absorption maximum 616, 656, 672 and 599 nm, respectively. The reaction was extremely rapid at room temperature, and the absorbance value remains unchanged for at least 1 week. The apparent stability constant of the complex were found to be 13.1 9.2, 11.4 and 12.3, and adheres to Beer's law for 0.05–3.50 μg per 10 ml of zinc. For more accurate analysis, Ringbom optimum concentration range was found from 0.08 to 3.20 μg per 10 ml of zinc. The apparent molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. Taking a constant concentration of metal ion and determining its concentration in the presence of large number of foreign ions tested the effect of foreign ions. The method was applied for determination of zinc in serum, human hair and pharmaceutical formulations, where excellent agreements between reported and obtained results were achieved. The relative standard deviation was better than 1.67%.

Polyurethane foam as a sorbent for continuous flow analysis: Preconcentration and spectrophotometric determination of zinc in biological materials

A simple and accurate procedure was developed to preconcentrate and determine zinc in biological matrices. A polyurethane foam (PUF) minicolumn was used for the first time for on-line preconcentration. This system was applied to preconcentrate zinc from aqueous solutions which is sorbed as zinc–thiocyanate complex. Then, the complex was eluted by water and zinc was determined by spectrophotometry using 4-(2-pyridylazo)-resorcinol. The method was validated by the analysis of several biological certified reference materials. The detection limit was 0.9 ng ml −1 and the RSD was 1.2% for 1 min preconcentration time. Generally, concentration of Fe(III), Al(III), Mo(VI), Ni(II), Mn(II), Cu(II), and Co(II) found in biological matrices did not interfere. Dynamic ranges of concentration from 20 to 100 ng ml −1 (1 min preconcentration time) and from 5 to 20 ng ml −1 (5 min preconcentration time) achieve a sample throughput of 20 and 8 samples per hour and a preconcentration factor of 8 and 32, respectively.

Determination of zinc in biological materials by sequential metal vapor elution analysis with atomic absorption detection

Determination of zinc in biological materials by sequential metal vapor elution analysis (column temperature; > 1150 K) with hydrogen carrier gas and an atomic absorption detector (AA) is described. The column was a molybdenum tube inserted a tungsten coil. Zinc was completely separated from Al, Ca, Cu, Fe, K, Na and Pb metals in the 1.3 ml min −1 of H 2 carrier gas at a column temperature of 1150 K and an atomization temperature of 1880 K. Under the experimental conditions, it became feasible to determine zinc in biological materials without the interferences of matrix elements observed in AA spectrometry. The relative standard deviation for zinc determination in biological materials by the method was 4.1–10% ( n = 3–4). The analytical results were in good agreement with the certified values in standard biological samples (NIST SRM). Consequently, an accurate determination of zinc in biological materials was possible immediately after only the acid-digestion.

Radiochemical determination of mercury, arsenic, cadmium, zinc and copper in biological materials

Extraction procedure for mercury, arsenic, cadmium, copper and zinc in biological materials is proposed. Mercury and copper are extracted with dithizone followed by the separation of mercury with tri-octyl-amine (TOA). Arsenic, cadmium and zinc are extracted as diethyldithiocarbamates. The procedure is applied for the analysis of some reference materials and autopsy human samples of kidneys, liver, heart, spleen and hair.

Selective separation of zinc from other elements on the amphoteric resin retardion 11A8 and its use for the determination of zinc in biological materials by neutron activation analysis.

The determination of the distribution coefficients of zinc and several other elements on the amphoteric resin Retardion 11A8 in NH4Cl, NH4Cl-NH3 and NH4Cl-HCl media has shown that zinc can be bound by the resin as cationic (aqua or ammine complex) or anionic chloride complexes, depending on the composition of the solution. It was possible to find conditions such that zinc could be held on the Retardion 11A8 column when changing from a cation-to an anion-exchange function and vice versa. A scheme developed for the selective separation of zinc from almost all other elements was subsequently used for the neutron activation determination of zinc in bovine liver and animal muscle certified reference materials.

Determination of traces of zinc in biological materials, wine, and alloys by fluorometry.

A simple, rapid, and selective method for the fluorometric determination of zinc has been developed based upon the formation of the salicylaldehyde thiocarbohydrazone (SATCH-Zn(II)) complex. The reaction is carried out at pH 4.6-4.9 in an aqueous-ethanol medium (52% v/v ethanol). The detection limit is 10 ng/mL and the relative standard deviations are +/-1.65% (15-100 ppb zinc), +/-1.70% (100-500 ppb zinc), and +/-2.22% (500-1000 ppb zinc). The effect of interferences was studied. The method has been applied to the determination of zinc in biological samples (prior to destruction of the organic matter by using a HNO/sub 3/-H/sub 2/O/sub 2/ mixture), wine, and alloys.

Rapid radiochemical separation in neutron activation analysis : Part 1. The use of C 18-bonded silica gel and selective complexation for determinations of manganese, copper and zinc in biological materials

A rapid radiochemical separation method based on the removal of metal ions by columns of C 18-bonded silica gel after selective complexation by 8-quinolinol, ammonium pyrolidinedithiocarbamate or cupferron is described for the determination of manganese, copper and zinc in neutron-activated biological materials. The removal of the metal ions, either by adsorption or by a combination of filtration and adsorption on columns of C 18-bonded silica gel, was investigated to optimise the separation procedure. Analysis of several National Bureau of Standards and International Atomic Energy Agency biological reference materials demonstrated the effectiveness of this technique. The method is simple and reliable and readily adaptable in all radiochemical laboratories. Furthermore, columns of C 18-bonded silica gel have been successfully recycled a number of times without deterioration.

Computerized potentiometric stripping analysis for the determination of cadmium, lead, copper and zinc in biological materials

Two different types of tinned mussels and a bovine liver reference sample have been analyzed for Zn, Cd, Pb and Cu by means of computerized potentiometric stripping analysis and atomic absorption spectrometry. The samples were digested by two different procedures, one employing nitric acid only and the other employing nitric and perchloric acids. It is shown that computerized stripping analysis can be used in samples containing high concentrations of electroactive organic nitro compounds, without sample deoxygenation.

The determination of copper and zinc in biological materials. A comparison of atomic absorption with spectrophotometry and neutron activation

A comparison is made between Atomic Absorption Spectroscopy, Neutron Activation Analysis and Soectrophotometric methods for the determination of Cu and Zn in brain and serum. The results of direct determinations for Atomic Absorption are compared wilh those obtained by standard addition.

Determination of lead, cadmium, copper and zinc in biological materials by anodic stripping polarography.

Abstract The high sensitivity of anodic stripping polarography and the simple equipment used make this technique very suitable for determining certain toxic elements, in particular lead and cadmium, as well as essential elements such as zinc or copper. These are found in biological and environmental systems in the concentration range of between nanograms per gram and a few hundred micrograms per gram of sample. The amount of sample required for one analysis is of the order of 100 mg, therefore the blank values introduced by the oxidizing mixture do not represent a serious limitation. After the decomposition of the sample by wet ignition no further separations are required. Copper and lead are determined from a solution made 1.0 M with respect to HC1. For zinc and cadmium the solution is buffered to pH 4.9–5.1. Values are presented for a set of samples among which are standard kale, orchard leaves, and bovine liver. The uptake of lead, zinc, and cadmium has been measured in carrots grown in the environment of a lead-mining area near Meŝica, Slovenia. The results are compared with those from a non-exposed site.

Simultaneous determination of copper, manganese and zinc in biological materials by means of neutron activation analysis and chelate extraction

Simultaneous determination of copper, manganese and zinc in biological materials by means of neutron activation analysis and chelate extraction

Determination of Zinc in Biological Materials by Atomic Absorption Spectrometry.

Determination of Zinc in Biological Materials by Atomic Absorption Spectrometry.

Chapter IV: Determination of zinc in biological materials

Chapter IV: Determination of zinc in biological materials

Determination of Zinc in Biological Materials

Determination of Zinc in Biological Materials

Chapter VI: Zinc in biological materials with special reference to its occurrence in the male reproductive organs

Chapter VI: Zinc in biological materials with special reference to its occurrence in the male reproductive organs

Zinc in Biological Materials with Special Reference to its Occurrence in the Male Reproductive Organs

Zinc in Biological Materials with Special Reference to its Occurrence in the Male Reproductive Organs