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Part A. Neutron activation analysis of selenium and vanadium in biological matrices. Part B. Isomeric transition activation in aqueous solutions of alkyl bromides
Abstract
A. Several procedures were evaluated for determination of selenium in biological fluids and vanadium in biological tissues by neutron activation analysis (NAA) employing $\sp{\rm 77m}$Se and $\sp{52}$V isotopes, respectively. NAA proved to be a sensitive method for determination of these two micronutrients which exist in parts per billion concentration range in most biological systems. Procedures for determination of total selenium, trimethylselenonium (TMSe) ion and selenite (SeO$\sb3\sp{2-}$) ion in urine and serum and for total selenoamino acids in urine were developed by utilizing anion exchange chromatography and molecular NAA. A pre-column derivatization of selenoamino acids with o-phthalaldehyde was necessary for their determination. The procedures were successfully applied to 5 serum samples and 54 urine specimens from normal and diseased subjects. The detection limits for determination of TMSe/SeO$\sb3\sp{2-}$ and total selenoamino acids were found to be 10 and 40 ppb, respectively. Also an analytical approach was developed for determination of trace vanadium in liver samples from normal and diabetic rats as well as human and cow. This procedure employed a wet digestion of the tissue followed by anion exchange chromatography and post-separation neutron bombardment. To evaluate the validity of the method, NBS-SRM 1577 and 1577a were used, and the results were compared with the certified values. The detection limit of the method was found to be one part per billion. B. Reactions of bromine-80 activated by radiative neutron capture and bromine-82 activated by isomeric transition were investigated in aqueous solutions of bromomethane and 1-bromobutane. Bromine-80 organic yields decreased with decreasing solute concentrations. The tendency for aggregation of the solute molecules diminished as the solute concentration approached zero where the probable state of the solute approached a monomolecular dispersion. Unlike reactions of $\sp{80}$Br born by $\sp{79}$Br(n,$\gamma)\sp{80}$Br reaction, the total organic product yields resulting from the $\sp{\rm 82m}$Br(I.T.)$\sp{82}$Br process showed no solute concentration dependence. This suggested that Auger effect Coulombic explosion has no applicability to alkyl bromides in liquid phase.
Subject Area
Analytical chemistry
Recommended Citation
Ebrahim, Alireza, "Part A. Neutron activation analysis of selenium and vanadium in biological matrices. Part B. Isomeric transition activation in aqueous solutions of alkyl bromides" (1988). ETD collection for University of Nebraska-Lincoln. AAI8907529.
https://digitalcommons.unl.edu/dissertations/AAI8907529