**4. Conclusions**

In this work we demonstrated for the first time the efficiency of the MEK-based solvent extraction process of 99mTc from a molybdenum-based liquid phased in an in-flow micro-scale regime, using a compact ZAIPUT separator device. Further developments will be carried out aimed at completing automation of the system thereof, including the dissolution and post-separation purification phases.

This system allows the extraction time and separation of technetium from the organic phase to be drastically reduced and can be used both to purify technetium from molybdenum metal targets in the direct cyclotron 99mTc production, as well as in indirect 99mTc production such as the <sup>99</sup>Mo production, by irradiating a natural molybdenum using a 14-MeV accelerator-driven neutron source.

**Author Contributions:** Conceptualization, P.M. and A.B.; data curation, P.M.; methodology, P.M.; investigation, P.M., L.U., L.M. and A.B.; writing—original draft preparation, P.M.; writing—review and editing, A.B.; supervision, A.D.; funding acquisition, J.E. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by National Institute for Nuclear Physics, grant number METRICS-CSN5.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
