Development of UV-Vis spectrophotometric method for determination of Mo release content in technetium-99m (99mTc) eluate from 99Mo/99mTc generator

Abstract

The chemical purity of 99mTc eluates is one of the essential parameters in quality control due to its application in nuclear medicine. Molybdenum release content or Mo breakthrough is a parameter of the chemical purity of 99mTc eluates resulted from the 99Mo/99mTc generator column. The amount of Mo breakthrough in the 99mTc eluate must be checked to ensure its quality in a safety manner. In this study, the measurement of the 99Mo breakthrough in the 99mTc eluate was developed using a UV/Vis spectrophotometer instrument quickly and simply. The determination of the molybdenum content is based on the colored complexes between molybdenum ion with thiocyanate (SCN) ligand. Tin (II) chloride (SnCl2) was used as a reducing agent to form a pentavalent Mo ion (Mo(V)) from Mo(IV). Then, the molybdenum (V) ions reacted with potassium thiocyanate (KSCN) to produce reddish-yellow complexes. The effect of conditions for testing, namely acid concentration, reducing agent concentration, KSCN concentration, has been optimized to obtain the optimum condition of complex formation. The final formulation was 2 mL of 10 % KSCN, 2 mL of 0.5% SnCl2 in 1M HCl, and 1 mL of Mo sample. The under optimum condition shows linearity from 1 ppm to 30 ppm Mo sample with regression coefficient 0,9983. The reddish-yellow color intensity of the complex Mo-SCN was measured at a maximum absorption wavelength of 461 nm after 40 minutes of initial mixing. The method had been successfully applied to 99mTc eluates from 99Mo/99mTc generator; however, the technique still requires further validation processes.