*Article* **Highly Efficient Micro-Scale Liquid-Liquid In-Flow Extraction of 99mTc from Molybdenum**

**Petra Martini 1,\* , Licia Uccelli <sup>1</sup> , Adriano Duatti <sup>2</sup> , Lorenza Marvelli <sup>2</sup> , Juan Esposito <sup>3</sup> and Alessandra Boschi <sup>2</sup>**


**Abstract:** The trend to achieve even more compact-sized systems is leading to the development of micro-scale reactors (lab-on-chip) in the field of radiochemical separation and radiopharmaceutical production. Technetium-99m extraction from both high and low specific activity molybdenum could be simply performed by MEK-driven solvent extraction if it were not for unpractical automation. The aim of this work is to develop a solvent extraction and separation process of technetium from molybdenum in a micro-scale in-flow chemistry regime with the aid of a capillary loop and a membrane-based separator, respectively. The developed system is able to extract and separate quantitatively and selectively (91.0 <sup>±</sup> 1.8% decay corrected) the [99mTc]TcO4Na in about 20 min, by using a ZAIPUT separator device. In conclusion, we demonstrated for the first time in our knowledge the high efficiency of a MEK-based solvent extraction process of 99mTc from a molybdenum-based liquid phased in an in-flow micro-scale regime.

**Keywords:** microfluidics; liquid–liquid extraction; technetium-99m; in-flow chemistry
