title: Detection enhancement in nano-channels using micro-machined silicon groove.
abstract: The present paper reports on an experimental study of the possibility to use a micro-machined detection groove to enhance the detection sensitivity in flat-rectangular nano-channels for ultra-rapid liquid chromatography separations. Transversally running detection grooves with three different axial widths (respectively, 2, 4 and 6 microm) and one depth (4.75 microm) were tested in glass and silicon channels for the whole range of detectable fluorescein isothiocyanate isomer I, FITC, concentrations. The groove with the most square-like cross-section (i.e., 4 microm wide and 4.75 microm deep) yielded the best combination of detection gain and minimal additional band broadening. In a 1cm long channel, the effective plate loss caused by the 4 microm wide groove would only be of the order of 20%, while the gain in S/N-ratio was of the order of a factor of 5. The detection groove concept yields larger gains in silicon channel substrates than in glass channel substrates, due to the larger stray light losses occurring in the latter.
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium. vfekete@vub.ac.be
authors.forename: Veronika
authors.initials: V
authors.lastname: Fekete
authors.forename: David
authors.initials: D
authors.lastname: Clicq
authors.forename: Wim
authors.initials: W
authors.lastname: De Malsche
authors.forename: Han
authors.initials: H
authors.lastname: Gardeniers
authors.forename: Gert
authors.initials: G
authors.lastname: Desmet
mesh_terms: D002853:Chromatography, Liquid / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008962:Models, Theoretical; D012825:Silicon / Q000737:chemistry*; D013997:Time Factors
chemical_list: D016650:Fluorescein-5-isothiocyanate; D012825:Silicon