Trace amounts of thyroxine in model samples (160.0 ng.ml–1 and 20.0 ng.ml–1), and thyroxine and 3,5,3-triiodothyronine in blood plasma were determined by sub- superequivalence isotope dilution analysis and radio-immunoassay technique. Hormones were labelled by125I. The separation of antibody-bound hormone from free hormone was performed by ultracentrifugation. The results show higher accuracy of the sub- super-equivalence isotope dilution method over that of radioimunoassay.
The theoretical errors of VCV, CVV variants and its subvariants are outlined and compared to previous study of other variants. Simple complex forming separation reaction is used and optimal conditions for the analysis are discussed.
The theoretical error of the CCV variant with a simple non-quantitative separation reaction M+LML has been studied. Equations of the relative error are derived and graphs at two regimes of radioactivity measurement of the reaction products are given: (1) for the registration of constant number of disintegrations and (2) for constant registration time of radioactivity measurement. Optimal conditions of analysis are discussed.
The theoretical error of both the CVC and VCC variants at non-quantitative complex forming reaction M+LML has been studied. The erros of analysis for the following analytical curve determinations are considered: (1) measurement with constant error of the analytical function, (2) measurement with registration of a constant number of disintegrations, (3) measurement at constant time of radioactivity measurement of isolated products. Conditions of isoconcentration point existence are determined. Intervals of parameters at which the relative error of the analysis result is comparable with that of the analytical curve are found out. The optimal conditions of analysis are discussed. Errors of both the CVC and VCC variants are compared with that of the CCV variant. Graphs of the theoretical error of analysis are given. The sub-super equivalent isotope dilution method (SSE IDA) has seven basic variants which can be classified by the CCV, CVC, VCC, VVC, VCV, CVV and VVV codes. The theroretical error of the CCV variant was studied earlier. In the present work, a study of errors of both the CVC and VCC variants is performed and extended to radioactivity measurement regimes that can be easily automated. The radioactive background of measurements is taken into account. Previous results and conclusions are corrected. Erros of both the CVC and VCC variants are compared with that of the CCV variant.
The theoretical curve and the theoretical error of the VVC variant of analysis with a simple complex-forming reaction have been studied and outlined. The existence conditions of the isoconcentration point, the interval of parameters in which the relative error of the analysis result is comparable with that of the analytical curve, have been determined. Possibilities of analysis in the quantitative and non-quantitative course of separation reaction are shown.
Theoretical errors of the VVV variant and its subvariants are outlined and confronted with the earlier study of other variants. Simple complex forming separation reaction is assumed. Optimal conditions of the analysis are discussed.
Authors:J. Lesný, Z. Koreňova, J. Tölgyessy, B. Novruzi, and A. Çela
Trace amounts of cadmium were determined by sub- and super-equivalence isotope dilution analysis in model solutions and water samples. Cd/II/ was labelled with109Cd and was extracted in CHCl3 as dithiozonate. AAS was chosen as reference analysis.
Authors:Z. Koreňová, J. Lesný, J. Jagnešáková, T. Miškovič, O. Rohoň, and J. Tölgyessy
Sub- and super-equivalence method of isotope dilution analysis /variant CCV/ was applied for the determination of trace of strontium in radioactive solutions in the presence of about 1000-times larger amount of calcium. DC-18-C-6 crown ether was used as a selective reagent. Picrate anion was chosen as a complementary ion.