Abstract: OXYGEN ATOM COORDINATED TECHNETIUM COMPLEXES FORMATION OF 99TcmVc WITH STANNOUS ION AS REDUCTANTAuthor Liu GuozhengMiao ZengxingWang YishanFang Jidong (Department of Isotope,China Institute of Atomic Energy,Beijing 102413) ABSTRACT The preparation of technetiumlabelled compound 99Tcmascorbate and the paper chromatographic determination system have been reported.The radiolabelled compound 99TcmVc from ascorbic acid and pertechnetate is readily formed with stannous ion as reductant at pH9.The labelling yield of 90%95% is easily achieved under the conditions ascorbic acid 10 g/L,SnCl22H2O5 mg/L.When the amount of SnCl22H2O exceeds 100 mg/L,99TcmVc can be stable (labelling yield90%) more than six hours. When the amount of SnCl22H2O is less than 10 g/mL,almost all 99TcmVc formed immediately can be changed into 99TcmECD through ligand exchange reaction,showing that technetium in 99TcmVc is in an oxidation state of five. Key words Ascorbic acidOxygen coordination atomLigand exchange reaction