SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM CONTENT IN 99m Tc SOLUTION VIA Mo-TGA-KSCN COMPLEXES FORMATION. Quality of Technetium-99m solution is determined from its radiochemical, radionuclidic and chemical purity. One of the major concern about chemical purity of Tc-99m from irradiated natural molybdenum is its molybdenum content or Mo breaktrough. Spectrophotometric method is one of method that could be applied for Mo determination in Tc-99m solution. Molybdenum (V) could form a colored complexes with potassium thiocyanate (KSCN) but Molybdenum (VI) must be reduced before formed a complexes with KSCN. Thioglycolic Acid (TGA) was used as reducing agent to obtain reduced Mo (Mo(V)). A series of optimization process was carried out to find optimum condition of complex formation for analysis purposes. Optimized condition were 3 mL of 25% HCl was added into a volume of Mo sample, followed by 200 µL of 10% TGA, 1 mL of 10% KSCN, and water addition up to 10 mL total volume. The method is linear over 2 ppm to 30 ppm Mo with regression coeffisient 0.9988±0.0007. The detection limit was 0.212 ppm Mo. Color of the complex has a stability of absorbance up to 120 minutes while stored at room temperature. No significant deviation occured when 1000 ppm of oxalic acid, methyl ethyl ketone and iron added into sample solution. This complexing method is suitable for spectrophotometric determination of molybdenum content in Tc-99m solution as a part of quality control process.

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Radiosynovectomy is a therapy performed on patients with acute-level arthritis (rheumatoid arthritis) as an alternative solution besides surgery. Radiosynovectomy is performed using a labeled compound with a particle size of 0.5-10 μm labeled with a β radioisotope. Hydroxyapatite (HA) is a 1-10 μm-sized compound found in bones with the components of Calcium (Ca) & Phosphorus (P). Phosphorus-32 (32P) is a radioactive form of Phosphorus which emits pure beta rays and is often used for therapy. Labelling HA with 32P tends to be easy to do with a substitution reaction, because phosphorus is the main constituent of HA. Phosphorus-32 was made by irradiating natural sulfur at the Bandung TRIGA 2000 reactor facility following the 32S (n, p) 32P reaction mechanism. The separation process of Phosphorus-32 was carried out by a distillation method followed by extraction with 0.01 N HCl accompanied by heating for 30 minutes. The Phosphorus-32 solution is then passed through a 3 gr cation exchange resin. Before Phosphorus-32 was used for Labelling of HA, a Radionuclide Purity test was performed with a gamma-MCA spectrophotometer and a Radiochemical Purity test using paper chromatography. The test results showed Phosphorus-32 had Radionuclide Purity > 99.99% and Radiochemical Purity > 96%. 0.5 mCi Phosphorus-32 which meets the quality test requirements is reacted with 7 mg Ha at pH 7. Then it is vortexed at 1500 rpm for 60 minutes with 70 ° C heating. HA-32P is separated using centrifugation into residual and supernatant fractions. Measure the radioactivity of both fractions with a dose calibrator. Labeling Yield HA with Phosphorus-32 was obtained 98%. Furthermore this HA is ready to be used in in vivo tests for radiosynovectomy.