Electrokinetic‐based injection modes for separative microsystems

Abstract

Miniaturization of analytical instruments has attracted a wide interest in Analytical Chemistry over the past decade because of the advantages such as reduced reagent consumption and shorter analysis time. For chips involving separation, injection is a key step to achieve efficient and sensitive analysis. Electrokinetic injection mode is mostly used in chips because it is easier to generate flow motion in microsystems via electric potential control at channel extremities than pressure-driven flow. The injection step usually involves several intersecting channels. For each injection design, different injection modes can be done, depending on electric field sequences and distributions. This paper is an up-to-date review of these different modes on a chip.

Elastomer Application in Microsystem and Microfluidics

“…The electrokinetic injection of defined sample plugs within single dimension microfluidic systems has been extensively studied, with the most widely used injector configurations including the cross, double-T, and triple-T topologies 74,75 , and extended configurations employing continuous sample injection leveraging flow switching techniques. Floating injection and pinched-injection methods 76,77 have been employed in simple cross-injectors for the controlled definition of small sample plugs, while double-and triple-T designs are generally employed for the introduction of larger sample volumes.…”

“…In general, PDMS is not the good materials of choice for high performance liquid chromatography. In such instance, other thermoplastics such as polyimide (PI) 85 , fuse silica capillary 75 , cyclic olefin copolymer (CoC) 86 , are recommended.…”

Microfluidic Device for Coupling Capillary Electrophoresis and Matrix-Assisted Laser Desorption Ionization-Mass Spectrometry

“…The CE sample loading approach in the microfluidic device is a modification of the typical ''double-T intersection'' sample loading. 33 Pressure-driven flow is used to load the sample in the CE channel and a pair of valves is used to capture a sample plug. This type of sample loading is an alternative of the typical sample loading using EOF.…”

Forced splitting of fractions in CE

“…Yet, despite clear benefits many challenges had to be addressed to make miniaturized CE successful. New materials [9], sample handling procedures [10,11] and detection techniques [12][13][14][15][16] were proposed to target problems specific to the microscale format.…”