Uranium(VI) On-Chip Microliter Concentration Measurements in a Highly Extended UV–Visible Absorbance Linearity Range

Abstract

The reduction of effluents deriving from analytical control is a serious concern in the nuclear industry, for both production and R&D units. In this work we report an alternative methodology for the standard UV-vis absorbance analyses for actinides concentration monitoring along the plutonium uranium refining extraction (PUREX) process. This methodology, based on photonic lab-on-a-chip (PhLoC) technology, enables drastic sampling reduction down to a few microliters and simultaneously allows to track concentrations over several orders of magnitude while maintaining a detection linearity range. A PhLoC microfluidic platform was specifically designed to allow online sample injection with zero dead volume connectivity and the on-chip spectrophotometric approach, based on a multiple optical path configuration, was tested for the determination of uranium(VI) concentrations from 0.1 to 200 g L, showing that linearity is maintained within high levels of confidence. These results provide the proof of concept for the transposition of current analytical methods for actinides, including plutonium, to microfluidic systems.

Photonic Lab-on-a-Chip analytical systems for nuclear applications: optical performance and UV–Vis–IR material characterization after chemical exposure and gamma irradiation

“…The objective of this final test was to evaluate a potential influence of the material and the manufacturing process (laser engraving + chemical edging for high-resolution glass structures, micro-milling for PMMA and cast melding for PDMS) on the performance of UV-visible spectroscopic measurements at the microfluidic scale. Thus, three geometrically identical chips have been manufactured, from the previously mentioned 3 different materials, based on the PhLoC design used in a previous work [4]. The first device was made of glass (cf.…”

“…In a previous work, the relevance of polydimethylsiloxane (PDMS) chips for Uranium (VI) concentration measurements by UV-Visible absorption on microliter volumes has been evidenced [4]. Following the promising results obtained, and in anticipation of a possible industrial implementation of this micro-analysis, two questions related to the chip durability must be examined: (1) the resistance to chemicals, that is shared by many chemical industrial sectors, and (2) the resistance to irradiation, that is more specific to nuclear applications.…”

“…In a previous work [4], preliminary tests have been made to observe the possible effects of gamma irradiation on PDMS and OSTEMER, two candidates for the realization of Uranium measurements chips. In this short communication, the chemical and irradiation resistance of these two materials, as well as that of other possible candidates for the manufacture of PhLoCs, is further examined.…”

“…In addition to a simple visual observation, that is sufficient to qualitatively evaluate the creation of defects and materials swelling, the precise evolution of the relevant optical properties is quantified using post-exposure UV-Vis and IR measurements. In a second step, two chips dedicated to absorptiometric analyses [4] have been made in the two most cheap and widely used materials, PDMS and PMMA, and their robustness has been compared to a glass (fused silica) made chip, the reference material.…”

Microfluidic lab-on-a-chip characterization of nano- to microparticles suspensions by light extinction spectrometry

“…In the quest for compact analytical platforms, different detection and characterization systems have already been integrated in LoC devices, based either on electrochemical [13], magnetic [14], or optical [15] transducers. While these devices have already been successful in the characterization of continuous (fluid) phases or effective media [12,[16][17][18], their development for the characterization of disperse phases (droplets, bubbles, crystals or aggregates) is still in its infancy. Classical approaches based on the temporal coherence of light (Dynamic Light Scattering, DLS) are limited in terms of flow dynamics and temperature control, while those based on angular scattering (Multi-Angle Static Light Scattering, MASLS) are difficult to implement at the microscale and limited to microparticles.…”