Radiochemical purity iodine

Radiochemical Purity Determination of the percentage of fixed iodine on the molecule is usually done by the radiochromatographic method. It can also be done by a precipitation test for proteins. Proteins are precipitated with trichloroacetic acid, and the different phases are counted in a gamma counter. 

C]ethyl iodide is synthesized with higher specific radioactivity and radiochemical purity from carbon monoxide by a palladium catalyzed reaction with methyl iodide followed by reduction and iodination (Eriksson and Langstrom 2001). 

The radiochemical purity of the product was found by measuring both the decay curve and y-spectrum Immediately after Irradiation. After the decay of I, the major long-lived Impurity detected was I formed by the (n,2n) reaction on the Iodine target. Active impurities were present to the extent of less than 1 ppm. 

Radiolabelled benzodiazepine antagonists 346 useful for the in vivo imaging and quantitation of benzodiazepine-GABA receptor sites in the human brain327,328 have been synthesized in 50-70% radiochemical yield and >98% purity by a one-step Pd-catalysed reaction329 between bis(tributyltin) and Ro 16-0154, 347, followed by electrophilic iodination of the tributyl tin compound 348 with no-carrier-added 125I and 123I (equation 148). 

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