Nonaqueous Micro Free-Flow Electrophoresis for Continuous Separation of Reaction Mixtures in Organic Media

Abstract

The continuous separation mechanism of micro free-flow electrophoresis (μFFE) is a straightforward, suitable tool for microscale purification of reaction mixtures. However, aqueous separation buffers and organic reaction solvents limit the applicability of this promising combination. Herein, we have explored nonaqueous micro free-flow electrophoresis for this purpose and present its suitability for a continuous workup of organic reactions performed in acetonitrile. After successful nonaqueous FFE separation of organic dyes, the approach was applied to continuously recover the photocatalyst [Ru­(bpy)3]2+ from a homogeneous, acetonitrile-based reaction mixture. This approach opens up possibilities for further downstream processing of purified products and is also attractive for recycling of precious catalyst species.

Efficient Escherichia coli (E. coli) Trapping and Retrieval from Bodily Fluids via a Three-Dimensional (3D) Microbeads Stacked Nano-Device

“…43 Our approach entirely relies upon for physical separation, which is robust and does not interfere with the host cellular materials. Furthermore, unlike other microfluidic-based approaches that require complicated instruments and operation, 22,[24][25][26][27][44][45][46] our approach only requires a small syringe pump and the miniaturized nanosieve device, thus it could be used for both lab-based or POC diagnosis.…”

“…18,19 Cell leakage is another challenge as the bacteria can deform to pass through the pores. In recent years, microfluidics-based approaches, such as inertial force separation, 20,21 hydrodynamic separation, 22,23 electrophoresis, 24,25 and acoustics separation, 26,27 have been developed to efficiently separate and detect pathogens; however, all of these methods have limitations, either require sophisticated microfluidic designs or complicated instruments. Therefore, physical barriers such as "T-junction" 28,29 and micro-obstacle arrays 30,31 were introduced to capture the cells from bodily fluids; yet, most of the bacteria sizes range between 0.5 to 5 µm, making the fabrication process challenging.…”

In situ monitoring of photocatalyzed isomerization reactions on a microchip flow reactor by IR-MALDI ion mobility spectrometry

“…However, UV-Vis absorption spectroscopy has a rather poor sensitivity due to the short optical path lengths found in microfluidic chips. An alternative method is fluorescence spectroscopy, which was utilized for the analysis of reaction progress [18] after chromatographic or electrophoretic separation [19][20][21]. A third method is surface-enhanced Raman spectroscopy, the suitability of which was demonstrated through several studies: by monitoring the progress of a Hantzsch synthesis in droplets [22], in a kinetic study of a platinum-catalyzed reduction of 4-nitrothiophenol to 4aminothiophenol [23], monitoring the Fenton degradation of rhodamine 6G [24] and the products of a multistep cascade reaction of glycerol to mesoxalic acid [25].…”

Visualization of Streams of Small Organic Molecules in Continuous-Flow Electrophoresis

“…The following supplementary files can be found on ChemRxiv: and c) photo of the assembled device. The numbers indicate: 6 mm mounting holes (1), outlet (2), the separation zone (3), sample inlet (4), electrolyte inlet (5), electrode channels (6), 4 mm mounting holes (7). The chip dimensions are 70 mm × 70 mm × 5.2 mm, and the dimensions of the separation zone are 50 mm × 50 mm × 0.2 mm.…”