An enhanced microfluidic chip coupled to an electrospray Qstar mass spectrometer for protein identification

Abstract

The combination of microfabricated fluidic systems (μFAB) and electrospray mass spectrometers (ESI‐MS) will provide multiplexed and integrated analytical systems for proteins and other biomolecules. Implementation of this novel approach requires the development of robust and user‐friendly μFAB devices. Here, we present new approaches that improve the robustness, user friendliness and performance of μFAB devices coupled to MS. First, we present the development of a convenient mount to connect a μFAB device to the ESI‐MS and the incorporation of filters in the reservoirs and exit of the μFAB. This mount facilitates interfacing and significantly reduces the chemical noise observed by the MS. Furthermore, we demonstrate improvements in sample handling and delivery by using either a nonaqueous electrolyte or a cationic coating on the surfaces in the μFAB device and transfer capillary. These improvements are applied to protein analysis by continuous infusion of proteolytic digests.

New advances in microchip fabrication for electrochromatography

“…Figure 4A and B depicts the use of a miniaturized LC using an injection unit (upper panel) and compares the resulting peaks (lower panel) [87]. Cleaning and sample injection may need special connections for high-pressure analytical procedures such as microchip electrochromatography and nanoLC [88][89][90][91]. To address this issue, a system was proposed where a microchip including a chromatographic column compartment was employed for EOF and also pressure-driven chromatography in a way where electrode vessels and fluid transfer fittings were placed in a large rack [88].…”

Possibilities to improve automation, speed and precision of proteome analysis: A comparison of two-dimensional electrophoresis and alternatives

“…Further advantages include reduced instrument size and weight, low dead volumes as well as reduced costs [27][28][29][30][31][32][33]. These devices currently provide a fast and established technique for the analysis of DNA.…”

Integrated system for high-throughput protein identification using a microfabricated device coupled to capillary electrophoresis / nanoelectrospray mass spectrometry

“…As an alternative to separations based on reversed phase chromatography, recent reports have described the analytical potentials of microfluidic devices coupled to MS for the analysis of peptides and protein digests [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. These microchips offer a convenient means of handling small liquid volumes with low sample dispersion while simultaneously obtaining separation and sensitive detection on devices of very small footprint.…”

“…These microchips offer a convenient means of handling small liquid volumes with low sample dispersion while simultaneously obtaining separation and sensitive detection on devices of very small footprint. In order to benefit from the rapid separation speed of these microfluidic devices, mass spectral detection often requires TOF [21,[23][24][25][26] or ion trap [17,20] mass analyzers. Recent reports have demonstrated the use of these devices for tracelevel analysis of peptide mixtures with submicromolar detection limits [17,23].…”