Chip‐based electrochromatography coupled to ESI‐MS detection

Abstract

In this study, we present the coupling of chip-based electrochromatography to MS using a glass chip with a monolithically integrated nanoelectrospray emitter. As separation column, an acrylate-based porous polymer monolith is implemented into the glass chip by photopolymerization. For the establishment and development of this method, we used a test mixture detectable with both fluorescence and ESI-MS. After successful evaluation of the approach with the test solutes, it was applied exemplarily for drug analysis such as high-speed separations of benzodiazepines in pharmaceuticals.

How electrospray potentials can disrupt droplet microfluidics and how to prevent this

“…This should considerably expand the application range of this new technology. Building upon our extensive experience in MS detection in glass chips, [56][57][58] such as chip-based HPLC/MS, 38 we decided to develop a new chip layout, which includes a monolithically integrated glass emitter for electrospraying individual droplets of the segmented chip-HPLC eluate. A prerequisite for inducing an electrospray at the emitter tip is the electrical contacting of the liquid to be sprayed.…”

On-Line Coupling of Chip-Electrochromatography and Ion Mobility Spectrometry

“…To develop an approach to couple ChEC with our previously designed ESI drift tube IMS system, ,− we first had to construct a functional microfluidic device. Here, we were able to build on previous work, where we combined ChEC with mass spectrometry. − …”

“…Furthermore, the manufacturing of the HPLC-chip is quite elaborate as it includes the integration of a packed column bed inside the chip, − which requires particle-retaining elements. In comparison, polymer monolithic columns, as frequently used in electrochromatography, are straightforward to integrate into a chip through photo-polymerization. − Electrochromatography is also technically less complicated because the eluent can be pumped electroosmotically with a compact high-voltage (HV) source rather than with HPLC pumps. Whereas electrochromatography has never really been able to prevail over HPLC in analytical practice, these advantages make it especially attractive in the context discussed here, since respective HV sources are required for the ESI–IMS operation anyway.…”

“…The use of a stationary phase in electrochromatography , with an electroosmotically pumped eluent leads to a mixed separation mode combining electrophoretic and chromatographic effects. The appealing combination of electrochromatography and IMS has, however, not yet been reported, which is especially true for the respective chip-based separation technique. ,,, This is the starting point for the current contribution, where we aim to develop the first approach to hyphenate chip-electrochromatography (ChEC) with IMS.…”

Analytical Techniques for Metabolomic Studies: A Review

“…This resulted in an unstable electrical connection between the tip of the capillary and the grounded electrospray needle [87,100]. Current drops were prevented by coating the capillary with a cationic polymer, shown in Figure 5B, thus reversing the direction of the EOF [85] with MS using a glass chip with a monolithically integrated nanoelectrospray emitter [111].…”