A Miniaturized Transverse Flow Gating Interface for the On-line Coupling of Solid-phase Extraction with Capillary Electrophoresis

Abstract

A miniaturized transverse flow gating interface (μ-TFGI) is presented for the on-line coupling of solid-phase extraction with capillary electrophoresis (SPE-CE). The fabrication and operation procedures of the μ-TFGI are described in detail. After the operation conditions were investigated and selected, the μ-TFGI was evaluated on an SPE-CE-UV setup using clenbuterol (CLB) as the test analyte. The preconcentration factors obtained with the SPE-CE-UV system and the SPE-UV part were 600 and 620, respectively. The plate numbers obtained within 3 min were 100000 and 80000 for automatic injection via the μ-TFGI and manual direct injection, respectively. The precisions were 2.4 -6.8% (RSD, %, n = 9) and 3.1% (RSD, %, n = 27) for the recovery (94.3 -101.9%) and migration time of CLB spiked in urine samples, respectively. These results demonstrate that the μ-TFGI has the ability to exactly and reproducibly transfer nanoliters of fractions from SPE onto CE with no degradation of the efficiencies of SPE and CE.

Developments in coupled solid‐phase extraction–capillary electrophoresis 2013–2015

“…Recently, Li et al. developed a miniaturized prototype of the transverse flow gating interface (μ‐TFGI) for the on‐line coupling of SPE and CE . Miniaturization of this interface resulted in a void volume of circa 11 nL.…”

“…A transverse flow of BGE through the gap is used to control the SPE eluate collection and injection [41]. As the SPE eluate is directly collected in the gap, valves and loops employed in previously developed interfaces are not required [41]. Miniaturization of this interface resulted in a void volume of circa 11 nL.…”

“…In this context, the transverse flow‐gating interface, first developed by the group of Jorgenson , is a cross‐like interface with SPE and CE positioned on opposite sides of the cross with a gap. A transverse flow of BGE through the gap is used to control the SPE eluate collection and injection . As the SPE eluate is directly collected in the gap, valves and loops employed in previously developed interfaces are not required in this configuration.…”