In Biological Materials

The neutron activation technique is particularly useful for the analysis of bound iodine in biological materials, since essentially all the radioiodine is present as iodide after irradiation. 

In a procedure for the determination of natural iodine in solid samples of biological materials (230), I and iodide carrier were added to the irradiated sample and the mixture was heated in a solution of chromium (VI) oxide in concentrated sulfuric acid. The mixture was cooled and diluted, and phosphorous acid was added to convert the iodine to iodide. The latter was then oxidized to elemental iodine by the addition of sodium nitrite, and the iodine was distilled into aqueous sodium hydroxide which contained Dowex 2-X8 resin (OH form). The mixture was shaken, the liquid decanted and the resin counted. Chemical yields of 80-90% were obtained. Where further purification was desired, the resin was washed with sodium nitrate solution to elute chlorine-38 activity, the most likely contaminant. Such treatment decreased the yields to 60-70%. 

I-labeled thyroxine was accounted for in the combustion process tamination factors from sodium-24, chlorine-38, bromine-80, and bromine-82 were 

A procedure for the analysis of natural iodine in aqueous solutions of iodohippuric acid (57) has utilized a freezing technique for the preparation of the sample for irradiation. Irradiation of a frozen sample rather than a solution has a number of advantages, the pressure in irradiation containers caused by the radiolysis of water is reduced substantially losses of iodine due to vaporization and also to adsorption on container walls are greatly minimized and interference from nuclides from container walls is avoided. 

In the procedure in question, the sample was irradiated at -40° and transferred in the solid phase to a glass container after a thin surface layer was 

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Bioassays are based on the growth response of vitamin-depleted rats or chicks to graded amounts of vitamin B 2 added in the diet. These assays are not specific for vitamin B 2 because factors, other than vitamin B 2 present in biological materials, produce a growth response. Because coen2yme primary form of natural vitamin 2 is light sensitive, assays should be carried out in subdued light. 

In biological materials, various nonspecific precipitants have been used in the gravimetric deterrnination of choline, including potassium triiodide, platinum chloride, gold chloride, and phosphotungstic acid (28). Choline may also be determined spectrophotometricaHy and by microbiological, enzymatic, and physiological assay methods. 

Neutron Activation Analysis (NAA) is one of the analytical methods recommended for low level Mo determination in biological materials. 

Bi-functional radio-analytical scheme, based on exchange and extraction column chromatography, which provides the reliable information on molybdenum and uranium contents in biological materials has been elaborated. The contribution of uranium fission reaction has been strictly monitored. The uncertainty of the results of Mo determination by the presented method is very low. 

Discussion. This method is based upon the formation of a fluorescent chelate between calcium ions and calcein [fluorescein bis(methyliminodiacetic acid)] in alkaline solution.29 The procedure described below30 has been employed for the determination of calcium in biological materials.31 ... 

Rapatz, G.L., Menz, L.J., Luyet, B.J. (1966). Anatomy ofthe freezing process in biological materials. 

The field of modified electrodes spans a wide area of novel and promising research. The work dted in this article covers fundamental experimental aspects of electrochemistry such as the rate of electron transfer reactions and charge propagation within threedimensional arrays of redox centers and the distances over which electrons can be transferred in outer sphere redox reactions. Questions of polymer chemistry such as the study of permeability of membranes and the diffusion of ions and neutrals in solvent swollen polymers are accessible by new experimental techniques. There is hope of new solutions of macroscopic as well as microscopic electrochemical phenomena the selective and kinetically facile production of substances at square meters of modified electrodes and the detection of trace levels of substances in wastes or in biological material. Technical applications of electronic devices based on molecular chemistry, even those that mimic biological systems of impulse transmission appear feasible and the construction of organic polymer batteries and color displays is close to industrial use. 

Table 7-1. Analytical Methods for Determining Methyl Parathion and Metabolites in Biological Materials... 

Coutselinis A, Kentarchou P, Boukis D. 1978. Concentration levels of endosulfan in biological material (report of three cases). Forensic Sci 11 75. 

Hurwood IS. 1976. Determination of endosulfan and metabolites in biological material. Residue 3 25-29. 

Davidson, I. W. F. and Secrest, W. L. "Determination of Chromium In Biological Materials by Atomic Absorption Spectrometry Using a Graphite Furnace Atomizer". Anal. 

Machata, G. and Binder, R. "The Determination of Lead, Thallium, Zinc and Cadmium Traces in Biological Material with Flameless Atomic Absorption". Z. Rechtsmed. (1973),... 

At present, the most promising methods for synthetic colorant analysis seem to be those based on separation approaches such as HPLC and capillary electrophoresis (CE). CE is the method of choice for the determination of synthetic dyes in biological materials while HPLC is generally a more suitable method for the identification and determination of hydrophobic natural pigments, having a better sensitivity and efficiency than CE. 

Kreuzer, F., Kimmich, H. P., Brezina, M. Polarographic Determination of Oxygen in Biological Materials in Medical and Biological Applications of Electrochemical Devices (ed.) Koryta, J. Chapt. 6, New York, Wiley 1980... 

Gardiner, P. H. E. Species Identification for Trace Inorganic Elements in Biological Materials. 141, 145-174(1987). 

De Goeij JJM, VorKERS KJ, Tjioe PS, and Kroon JJ (1978) NBS SRM 1569 Brewer s yeast Is it an adequate standard reference material for testing chromium determination in biological materials. Radiochem Radioanal Letters 35 139-146. 

Kosta L, and Byrne AR (1982) Analytical evaluation of comparative data on trace elements in biological materials. J Radioanal Nud Chem 69 117-129. 

Copper appears as the a2-globulin ceruloplasmin in the human body (Sarkar 1994). Deficiency of this protein in serum is characteristic of both Menkes and Wilson s diseases. Wilson s disease is an abnormal storage of Cu(II) in body tissues. Cu(II) in biological material can be determined by spectrophotometry or by FAAS, ceruloplasmin in serum by a spectrophotometric method. 

Aluminium is the most abundant element of the lithosphere. Although a large number of persons are exposed world-wide to Al, the incidence of pulmonary effects is low (Schaller et al. 1994). In the 1970 s the effect of Al appearing in dialysis solutions on the central nervous system has become weU known. Increased Al could also be detected in several brain regions of patients with Alzheimer s disease. For the determination in biological materials the most widely used method is GF-AAS. 

Error 1 CRMs completely or partly not identical with the matrix to be analyzed Ber-mejo-Barrera et al. (1999) studied enzymatic hydrolysis procedures using pronase E as sample pretreatment for multi-element - Cu, Fe, Mg, Zn, Ag, As, Cd, and Pb -determination in biological materials, mussel samples and human hair. 

Bermejo-Barrera P, I Ernanuez-Nocelo S, Moreda-PiSeiro A and Bekmejo-Barrera A (1999) Useftilness of enzymatic hydrolysis procedures based on the use of pronase E as sample pre-treatment for multi-element determination in biological materials. J Anal At Spcctrom 14 1893-1900. 

Murayama, K. and Shindo, N., Recommended method for the analysis of amino acids in biological materials, /. Chromatogr., 143, 137, 1977. 

Guilmette RA, Bay AS. 1981. Radio assays of americium or curium in biological material by isoctyl acid phosphate solvent extraction and a liquid scintillation counting. Anal Chem 53 2351-2354. 

Hafez MB, Hafez N. 1992. Quantitative determination of americium in biological materials. J Radioanal Nucl Chem 164(2) 81-89. 

A Spectrochemical Study of the Normal Ranges of Concentration of Certain Trace Metals in Biological Materials. Journal of Nutrition. 19 (1940) 579-592. 

The analysis of extraterrestrial matter is concentrated on the detection of nucleic acid and protein building blocks, i.e., N-heterocycles and amino acids. The search for such compounds began immediately after the fall of the Murchison meteorite. Twenty-two amino acids were detected in it as early as 1974 eight of them pro-teinogenic, ten which hardly ever occurred in biological material, and four which were unknown in the biosphere. Up to now, about 70 amino acids have been identified (Cronin, 1998), the most common being glycine and a-aminoisobutyric acid. The latter is a branched-chain amino acid with the smallest possible number of carbon atoms. The most frequently found amino acids occur in concentrations of... 

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