Liquid–liquid extraction of uranium(VI) with Aliquat® 336 from HCl media in microfluidic devices: Combination of micro-unit operations and online ICP-MS determination

• Liquid–liquid extraction of U(VI) in HCl by Aliquat 336 in microchip is performed.
• The influence of various parameters on the extraction performances is investigated.
• The study of the stripping step for different microsystem lengths is proposed.
• Two ways of coupling of extraction and stripping are proposed.
• The coupling of the stripping step in chip with ICP-MS measurement is performed.

The analysis of radionuclides is carried out according to operating protocols which include a series of chemical operations such as separation/purification steps and therefore is usually time-consuming, complex and difficult to put in place in a hostile environment (gloves box). In the present work, the liquid–liquid extraction of uranium in HCl media by Aliquat® 336 was performed in microsystem to demonstrate the potential of miniaturization in radiochemistry compared to classical protocols (decrease in volumes, analysis time, radiations received and feasibility of automation). Through the investigation of the influence of different parameters (flow rates, length of the microchannel, specific interfacial area), it was shown that the same performances of liquid–liquid extraction can be obtained in microsystem and in batch. Then, the coupling of different micro-unit operations for continuous process was performed to highlight the advantages of the miniaturized analytical techniques. The online ICP-MS determination of uranium(VI) was successfully coupled with the stripping of the latter from pre-loaded organic phases in microsystem, which constitutes a proof of concept and a first step towards a global analytical process with continuous flow.