Efficient electrospray ionization from polymer microchannels using integrated hydrophobic membranes.
A simple process for realizing stable and reliable electrospray ionization (ESI) tips in polymer microfluidic systems is described. The process is based on the addition of a thin hydrophobic membrane at the microchannel exit to constrain lateral dispersion of the Taylor cone formed during ESI. Using this approach, ESI chips are shown to exhibit well-defined Taylor cones at flow rates as low as 80 nL min(-1) through optical imaging. Furthermore, stable electrospray current has been measured for flow rates as low as 10 nL min(-1) over several hours of continuous operation. Characterization of the electrospray process by optical and electrical monitoring of fabricated ESI chips is reported, together with mass spectrometry validation using myoglobin as a model protein. The novel process offers the potential for low-cost, direct interfacing of disposable polymer microfluidic separation platforms to mass spectrometry.
Department of Mechanical Engineering, University of Maryland, College Park, MD, USA.
Ying-Xin
YX
Wang
Jon W
JW
Cooper
Cheng S
CS
Lee
Don L
DL
DeVoe
D008565:Membrane Proteins / Q000737:chemistry*; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D009211:Myoglobin / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
D008565:Membrane Proteins; D009211:Myoglobin; D011108:Polymers