On-chip coupling of electrochemical pumps and an SU-8 tip for electrospray ionization mass spectrometry

Abstract

We present the integration of a cyclo olefin copolymer microfluidic chip with electrochemical pumps and an SU-8 tip for electrospray ionization mass spectrometry. The electrochemical pump, using electrolysis as an internal pressure source, was fabricated directly on the surface of the polymer chip. The triangular SU-8 emitter tip was fabricated on a glass wafer using standard photolithography. After release from the glass wafer, this tip was aligned to the microchannel and bonded between two polymer plates. The electrochemical pump and the electrospray tip were tested with electrospray ionization mass spectrometry. Mass spectrometry confirmed the stability of the electrochemical pump and the electrospray tip.

Cyclic olefin polymers: emerging materials for lab-on-a-chip applications

“…COP chips have been used as electrospray emitters, where the liquid sample is ionised and turned into an aerosol (Kameoka et al 2002;Liu et al 2007;Park et al 2008a;Shinohara et al 2008;Yang et al 2004Yang et al , 2005a. Bedair and Oleschuk (2006) reduced clogging and droplet spreading problems by utilising a porous polymer monolith at the end of the channel.…”

Toward Integrated Molecular Diagnostic System (<formula formulatype="inline"><tex Notation="TeX">$i$</tex></formula> MDx): Principles and Applications

“…Many other sample preparation methods exist such as a preconcentration module for concentrating extremely low analytes [51] and embedded actuation system (e.g. electrochemical pump [52]. …”

Materials and methods for the microfabrication of microfluidic biomedical devices

“…Thermal processes (Yang et al ., 2002;Chen et al ., 2005;Park et al ., 2008;Ogonczyk et al ., 2010) use compression at a temperature around its glass transition temperature for bonding slabs or thin foils, and results in an average bonding strength of 0.55 MPa. Chemical bonding induced by the modifi cation of surface chemistry can be achieved by the plasma treatment (Klintberg et al ., 2003;Wang et al ., 2008) or the introduction of active surface groups (Lee and Ram, 2009), and shows a highest bonding strength of over 6.8 MPa.…”

“…Similar to other polymers, fabrication methods for COC/COP can be categorized as direct structuring methods, such as laser ablation (Sabbert et al ., 1999;Jensen et al ., 2004;Bundgaard et al ., 2006) and micro-milling (Bundgaard et al ., 2006;Grumann et al ., 2006), and replication methods, such as injection molding (Kim and Kwon, 2009;Pakkanen et al ., 2002;Appasamy et al ., 2005;Lee et al ., 2005;Ito et al ., 2007;Kalima et al ., 2007;Steigert et al ., 2007;Angelov and Coulter, 2008;Schütte et al ., 2010), hot embossing ( Fig. 1.15) (Kameoka et al ., 2001;Yang et al ., 2005;Bhattacharyya Fredrickson et al ., 2006;Liu et al ., 2007;Faure et al ., 2008;Park et al . 2008;Illa et al ., 2009), and nano-imprint lithography (Bilenberg et al ., 2005;Gourgon et al ., 2005;Nilsson et al ., 2005;Gustafsson et al ., 2008).…”

“…COP-based microchannels have also been used in solid phase extraction where either the interested analytes or the undesired impurities are retained by the stationary phase (Gustafsson et al ., 2008;Illa et al ., 2009). Moreover, COP-based electrospray emitters have been used for mass spectrometry where the ionized analytes are separated depending on their interaction with external electric and/or magnetic fi elds (Jun Kameoka et al ., 2002;Yang et al ., , 2005Park et al ., 2008; Shinohara et al ., 2008). Since COP is relatively transparent compared to other polymers at shorter wavelengths (240-360 nm), it can be used as optical components such as micro lenses (Appasamy et al ., 2005), photonic crystals (Bilenberg et al ., 2004), and optical waveguides (Okagbare et al ., 2010).…”