The separation and detection of PET tracers via capillary electrophoresis for chemical identity and purity analysis

• CE/UV was assessed as a chemical purity analysis platform for PET tracers.
• Two samples of PET tracers and their impurities were analyzed as examples.
• The performance of CE was compared with the accepted performance of HPLC.
• CE provided shorter analysis times, μ-molar LOD and sufficient reproducibility.
• CE/UV was introduced as a novel method for the quality control of Kryptofix2.2.2.

CE coupled with UV detection was assessed as a possible platform for the chemical identity and purity analysis of positron emission tomography (PET) tracers using [18F]FAC and [18F]FLT as examples. Representative samples containing mixtures of the tracers plus well-known impurities, as well as real radioactive samples (formulated for injection), were analyzed. Using MEKC with SDS in a neutral phosphate buffer, the separation of all compounds in the samples was achieved with baseline resolutions in less than 4.5 min and 3 min for FLT and FAC samples, respectively. In comparison to the gold-standard for chemical analysis (i.e. HPLC/UV), we have demonstrated improvements in analysis times, and comparable LOD. Although the reproducibility in migration time is slightly lower than that of the HPLC, identification of the compounds was still possible due to good peak separation. In addition, we show that CE can be used to identify and quantify Krytofix2.2.2 (a toxic and commonly used phase transfer catalyst) in less than 2 min and with a LOD of 45 μg/mL (non-optimized). These results demonstrate adequate performance for chemical identity and purity analysis. Combined with the potential for miniaturization into a microchip format, these results suggest the potential of CE as an integral part of a miniaturized quality control system for PET tracers.

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