Selenium In Biological Samples Research Articles

Determination of selenium in biological samples by electrochemical preconcentration and atomic absorption spectrometry

For the determination of selenium in biological materials the samples are digested with an HNO3/H2SO4/ V2O5 or an HNO3/HClO4 mixture. Selenium is then electrolyzed onto a platinum wire, followed by atomic absorption spectrometry with simultaneous electrothermal and flame atomization. Results for the reference materials Bovine Liver and Albacore Tuna are reported (1−3±0.2 ppm Se).

High sensitivity PIXE determination of selenium in biological samples using a preconcentration technique

The importance of selenium in biological and organic matrices is well established; a very sensitive and fast analytical method is necessary to investigate its role deeply. A preconcentration technique is described that allows selenium detecting at the ppb level in biological samples in a short time. It involves first the decomposition of the organic matrix and then the precipitation of selenium using tellurium both as the coprecipitant and as the internal standard. For serum samples the optimal range of volume to be used is 0.1–2 ml. The sensitivity is obtained at the ppb level after about 10 min irradiation time. The accuracy of the method is checked by comparison with the direct palletization method and by using a standard reference material.

Method for the determination of selenium in biological samples by hydrogen selenide evolution electrothermal atomic absorption

This paper deals with studies on the method of selenium determination in biological samples and several fundamental experiments using the rapid semi-automized electrothermal atomisation atomic absorption spectro-photometric procedure.Samples were digested with a mixture of nitric acid and perchloric acid, then selenium was determined by hydrogen evolution electrothermal atomic absorption method. Coexistence of high concentrations of Fe, As, Ni and Cu interferes with selenium determination. However, these interferences could be negligible in the case of determination of biological samples.The sensitivity of this method is sufficient for application to the determination of selenium in biological samples.

INAA determination of selenium via77mSe in plasma, semen and hair samples from beef and dairy bulls

Interest in the element selenium with respect to its biological significance has been steadily increasing for the last ten years. Neutron activation analysis has long been used for the accurate determination of selenium in biological samples usually via75Se. More recently activation analysts having access to high flux reactors with rapid delivery pneumatic tube facilities; have successfully employed77mSe. This approach, which is much faster, is particularly well suited to the Missouri University Research Reactor (MURR). The specific interest concerning bulls has to do with the involvement of selenium in the reproductive system. Selenium analysis methodology and data on plasma, semen and 22 tissues from both beef and dairy bulls are presented.

Determination of selenium in biological samples by hydride generation and atomic-absorption spectroscopy.

Hydride generation followed by atomic-absorption spectroscopy has been used to determine the concentrations of selenium in 100-µl volumes of whole blood, plasma and erythrocyte suspensions following digestion of the samples with nitric and sulphuric acids. Analyses of human and animal sera agreed well with those obtained by other workers for selenium concentrations in the range 6–160 µg l–1. Relative standard deviations of 4.0–4.5% were obtained for replicate analyses of human plasma and whole blood containing selenium at concentrations of 120–144 µg l–1.

Improved method for selenium determination in biological samples by gas chromatography

A gas chromatographic assay employing electron-capture detection for the determination of selenium in biological samples is reported. A calibration curve of 4-nitro- o-phenylenediamine derivative of selenium as a function of peak area was linear from 5–1000 pg. The limit of detection for the electron-capture detector was approximately 0.5 pg. Recoveries of selenium added to various biological materials ranged from 95–105%. This procedure reduces the number of transfers thereby reducing errors associated with losses or contamination. One advantage of the present method is that interfering compounds occurring in previously employed chromatographic methods are eliminated. This procedure can be used for routine microanalysis of selenium. Samples containing less than 2 ng selenium in 200 μl of biological fluid can be routinely analyzed using this method.

Rapid determination of trace amounts of selenium in biological samples by gas chromatography with electron-capture detection.

A rapid, simple and sensitive method of determining total selenium in biological samples is described. Selenium(IV) reacts with 1,2-diamino-3,5-dibromobenzene to form 4,6-dibromopiazselenol, which is detected by means of a gas chromatograph equipped with an electron-capture detector. In order to complete the mineralisation of selenium in seven organic compounds, a wet digestion method was employed. Thirty determinations can be made in 8 h by a modified method. Trace amounts of total selenium in NBS standard reference materials, human blood and serum were determined and compared with the certified or reported values.

Etude critique de la determination par spectrometrie d'absorption atomique sans flamme du selenium dans les milieux complexes apres extraction a l'aide d' o-diamines aromatiques et ajout de nickel(II)

Critical study of the graphite-furnace atomic absorption determination of selenium in biological samples after extraction with aromatic o-diamines and addition of nickel(II) A new method for the determination of traces of selenium in natural samples is proposed. After digestion with nitric, sulfuric and perchloric acids, selenium is quantitatively converted to the tetravalent state with perhydrol. Reaction with an aromatic o-diamine gives the corresponding piazselenol which can be extracted into toluene and determined by atomic absorption spectrometry after addition of nickel(II). Calibration graphs are linear in the range 0–1.5 ppm Se. A critical study shows the advantages of the method.

Determination of selenium in biological samples by gas—liquid chromatography with electron-capture detection

Selenium can be determined quantitatively in biological samples after nitric acid—magnesium nitrate digestion and formation of 5-nitropiazselenole, by extraction into toluene for gas—liquid chromatography with electron-capture detection. The method is suitable for the determination of selenium in orchard leaves, bovine liver and human placenta, hair, blood and urine.

Determination of selenium in biological samples by solvent extraction-graphite furnace atomic absorption spectrometry

Determination of selenium in biological samples by solvent extraction-graphite furnace atomic absorption spectrometry

Application of Flameless Atomization to the Atomic Absorption Determination of Selenium in Biological Samples

Abstract Trace amounts of selenium in biological samples were estimated by atomic absorption utilizing a Varian carbon rod flameless atomizer. Samples were digested with nitric perchloric acids, selenium was separated from the interfering sample matrices by reduction-precipitation with ascorbic acid, redissolved in acid and five microliter aliquots were taken for analysis. For a variety of samples, the results were comparable with, but somewhat lower than, levels determined by fluoro-metry. Sensitivity and detection limit are 80 ng/ml and 60 ng/ml respectively; absolute sensitivity and detection limit are 4×10 −10 g and 3×10 −10 g respectively.

A GC-MS Procedure for the Measurement of Dopamine in Mouse Striatal Tissue

Abstract A gas chromatographic-mass spectrometric (GC-MS) method for measuring dopamine levels in brain tissue has been developed. Deuterated dopamine was prepared by exchange of the aromatic hydrogens with deuterium. The method involves adding a known amount of deuterated dopamine to the extraction medium or vessel and extracting the brain sample. The sample is acylated with pentafluoropropionic anhydride, and an aliquot of the derivative in benzene injected into a gas chromatography-mass spectrometry-computer system. The ion fragments, m/e = 428 and 431 respectively, of the protium and deuterium form of dopamine pentafluoro-propionate are detected. From the relative intensities of the two forms the concentration of dopamine in the brain samples is determined. Trace amounts of selenium in biological samples were estimated by atomic absorption utilizing a Varian carbon rod flameless atomizer. Samples were digested with nitric perchloric acids, selenium was separated from the interfering sample matrices by...

Rapid Colorimetric Determination of Microgram Amounts of Selenium in Soils and Biological Samples, Using Millipore Filters

Abstract A method is described for the determination of selenium in biological samples or soil samples, following acid digestion or distillation as the tetrabromide, respectively. The selenium is reduced to the element by ascorbic acid. The element is filtered and collected on a white Millipore filter. The intensity of the coloration of the filter is used as a measure of the selenium content. The range of the method is from 0.2 μg selenium to > 0.1 mg selenium. Complete analysis time for a single biological sample is about 60 minutes, while that for a soil sample is less than 2 hours. Control of variables is not critical.