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Shape‐anchored porous polymer monoliths for integrated online solid‐phase extraction‐microchip electrophoresis‐electrospray ionization mass spectrometry
Author(s) -
Nordman Nina,
BarriosLopez Brianda,
Laurén Susanna,
Suvanto Pia,
Kotiaho Tapio,
Franssila Sami,
Kostiainen Risto,
Sikanen Tiina
Publication year - 2015
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201400278
Subject(s) - monolith , materials science , solid phase extraction , electrospray , chromatography , electrophoresis , capillary electrophoresis , mass spectrometry , electrochromatography , electrokinetic phenomena , elution , analytical chemistry (journal) , porosity , capillary electrochromatography , chemistry , nanotechnology , composite material , biochemistry , catalysis
We report a simple protocol for fabrication of shape‐anchored porous polymer monoliths (PPMs) for on‐chip SPE prior to online microchip electrophoresis (ME) separation and on‐chip (ESI/MS). The chip design comprises a standard ME separation channel with simple cross injector and a fully integrated ESI emitter featuring coaxial sheath liquid channel. The monolith zone was prepared in situ at the injection cross by laser‐initiated photopolymerization through the microchip cover layer. The use of high‐power laser allowed not only maskless patterning of a precisely defined monolith zone, but also faster exposure time (here, 7 min) compared with flood exposure UV lamps. The size of the monolith pattern was defined by the diameter of the laser output (∅500 μm) and the porosity was geared toward high through‐flow to allow electrokinetic actuation and thus avoid coupling to external pumps. Placing the monolith at the injection cross enabled firm anchoring based on its cross‐shape so that no surface premodification with anchoring linkers was needed. In addition, sample loading and subsequent injection (elution) to the separation channel could be performed similar to standard ME setup. As a result, 15‐ to 23‐fold enrichment factors were obtained already at loading (preconcentration) times as short as 25 s without sacrificing the throughput of ME analysis. The performance of the SPE‐ME‐ESI/MS chip was repeatable within 3.1% and 11.5% RSD ( n = 3) in terms of migration time and peak height, respectively, and linear correlation was observed between the loading time and peak area.