A Polymeric Microfluidic Chip for CE/MS Determination of Small Molecules

Abstract

A polymeric microfluidic chip made of Zeonor 1020 was fabricated using conventional embossing techniques to perform capillary electrophoresis for selected ion monitoring and selected reaction monitoring mass spectrometric detection of small molecules. A silicon master was microfabricated using photolithographic and dry etching processes. The microfluidic channel was embossed in the plastic from a silicon master. The embossed chip was thermally bonded with a Zeonor 1020 cover to form an enclosed channel. This channel (60-microm width, 20-microm depth, 2.0- and 3.5-cm length) provided capillary electrophoresis (CE) separation of polar small molecules without surface treatment of the polymer. A microsprayer coupled via a microliquid junction provided direct electrospray mass spectrometric detection of CE-separated components. An electric field of 0.5-2 kV/cm applied between the microsprayer and a separation buffer reservoir produced a separation of carnitine, acylcarnitine, and butylcarnitine with separation efficiencies ranging from 1,650 to 18,000 plates. Injection quantities of 0.2 nmol of these compounds produced a separation of the targeted polar small molecules without surface treatment of the polymer-abundant ion current signals and baseline separation of these compounds in less than 10 s. These results suggest the feasibility of polymeric chip-based devices for ion spray CE/MS applications.

Deposition of chemically reactive and repellent sites on biosensor chips for reduced non-specific binding

“…[1,2,3] However, there is a need for surface modification of the COP substrates to create a suitably reactive and stable surface in an industrially feasible cost effective manner. The wet chemistry methods are usually time consuming and work reproducibly only in few selected solvents.…”

Generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate: Effect of emulsifier and oil types

“…Although the frequency of droplet generation can be as high as 12,000 Hz for water-in-oil droplets [4], the throughput in terms of volume flow rate of the disperse phase is very low because the droplets are formed from a single microchannel. These microfluidic devices are investigated for capillary electrophoresis [5], immunoassays [6], cellomics [7], proteomics [8], DNA analysis [9], etc.…”

Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento

“…[39][40][41][42][43][44][45][46] Com este propósito, diferentes configurações de interfaces já foram desenvolvidas, tal como acoplamento em linha com MALDI-MS. [47][48][49] Jin et al 50 apresentaram um trabalho revolucionário construindo um sistema de reator enzimático em linha no qual a bomba seringa, tradicionalmente usada para gerar o fluxo hidrodinâmico, foi substituída pelo fluxo eletroosmótico, levando as proteínas até o reator enzimático. As enzimas foram imobilizadas em uma fase estacionária e neste sistema foi possível, em uma única etapa, promover a digestão de proteínas em 12 min com um sistema integrado de eletroforese na forma de um chip e sua caracterização em um sistema MALDI-TOF-TOF (time of flight).…”