Current methods for analysis of the purity of radiometals include the DOTA/TETA titration and ion chromatography (IC). Titrations provide only the effective specific activity and may suffer from inconsistent results depending on labeling conditions, while IC is limited by sensitivity and requires the use of high concentrations and activities of radiometals. To overcome these problems, a rapid and sensitive LC-MS approach using both traditional and stable-isotope labeled agents was developed. 13C/2H-labeled and traditional 12C/1H DOTA analogs were synthesized and chelated with a known concentration of transition metals (including Fe(III), Ni(II), Cu(II) Co(II), Zn(II)) and 2-5 mCi of Cu-64, respectively. This mixture was analyzed by LC-MS, and data showed that each metal ion in the Cu-64 solution can be quantified by comparing the MS peaks of light (Cu-64 solution) and heavy (metal impurities) complexes. This approach appears very promising for the rapid analysis of various radiometals, such as Ga-68 and Cu-64. 

Rapid and sensitive LC-MS approach to quantify cold metal impurities in radiometals to accurately determine effective specific activity

243rd National Meeting (2012)

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