Determination of pertechnetate by liquid chromatography with reductive electrochemical detection

A method utilizing liquid chromatography with electrochemical detection has been developed for the determination of total TcO4-(/sup 99m/TcO4- and /sup 99m/TcO4-) in 99Mo//sup 99m/Tc generator eluents. Pertechnetate, which is the starting material for the preparation of many diagnostic radiopharmaceuticals, is generally present in these eluents in the concentration range of 5 X 10-8 M to 5 X 10-6 M. No sample pretreatment is necessary since impurities and other components are separated by the high-pressure liquid chromatography (HPLC) NH2-bonded column. By use of both static mercury drop (SMDE) and solid electrode detectors, in conjuction with rigorous deoxygenation procedures, total TcO4- in generator eluents is readily determined. A severe electrode fouling phenomenon limits the use of solid electrode detectors to TcO4- concentrations less than 10-7 M, the working range for a carbon electrode being 8.5 X 10-9 to 1.0 X 10-7 M. The working range for the SMDE is 2.1 X 10-8 to 1.0 X 10-4 M TcO4-