Determination of iodine in urine by neutron activation analysis. Application of the Szilard-Chalmers effect

Abstract

viated greater flow rates and are a disadvantage when these small particles are used.Current investigations of the utility of these types of supports in the separation of complex mixtures such as lipids in GLC and TLC will be reported soon.

Determination of iodoamino acids and thyroid hormones in a urine matrix by neutron activation analysis

“…We developed a procedure for the desalinization of urine, employing gel filtration with a subsequent separation by HPLC and radioanalysis for the individual iodinated compounds by neutron activation. It must be realized (6,23) that a preirradiation-jseparation of the iodine compounds and the iodide ion must, be accomplished before neutron irradiation and radioassay because Szilard-Chalmers reactions of the iodine hot atom will result in the breaking of the ligand from the biological molecule. In a liquid water matrix such as urine the preferential reactions will be the formation of the 128Ilabeled iodide ions.…”

“…Effective desalination by the gel filtration and HPLC steps reduced the MNa and ,38C1 activities, after neutron 0 Critical level-concentration that must be exceeded in order to yield the decision "detected". 6 Detection limit-minimum detectable concentration that will give a signal exceeding LC 95% of the time. c Detection limitconcentration necessary to obtain relative standard deviations as small as ± 10%.…”

“…The determination of total and hormonal iodine in serum and urine is important for the study of thyroid physiology in health and disease. The two main techniques currently used for total iodine are colorimetric procedures (1,2) [involving oxidation-reduction catalysis of the As(III)-Ce(IV) system] and neutron activation analysis (NAA) (3)(4)(5)(6) involving multiple wet-chemical pre-or postirradiation operations such as oxidation and reduction, solvent extraction, use of anion resins, distillation, and/or precipitation. Currently there is more interest in the determination of iodoamino acids and hormonal iodine in various biological matrices.…”

“…The total iodine concentration in clinical urine samples can vary from ~0.1 pg/mL to over 2000 jug/niL with a mean concentration of approximately 0.2 pg/mL urine. While there have been various colorimetric (1,2) and neutron activation analysis (3)(4)(5)(6) procedures for total iodine determinations in urine, there are no NAA techniques for determining iodoamino acids and hormonal iodine. One characteristic of the thyroid hormones T2, T3, and T4, and their precursors MIT and DIT is that they contain mI, the only stable isotope of iodine.…”

Storage and Pre-Neutron Activation Analysis Treatment for Trace Element Analysis in Urine

“…Our intent in this review is not to repeat Cornelis's study but to add to it from our experience in work involving the urine matrix [2][3][4][5][6][7].…”