title: Integration of pillar array columns into a gradient elution system for pressure-driven liquid chromatography.
abstract: A gradient elution system for pressure-driven liquid chromatography (LC) on a chip was developed for carrying out faster and more efficient chemical analyses. Through computational fluid dynamics simulations and an experimental study, we found that the use of a cross-Tesla structure with a 3 mm mixing length was effective for mixing two liquids. A gradient elution system using a cross-Tesla mixer was fabricated on a 20 mm × 20 mm silicon chip with a separation channel of pillar array columns and a sample injection channel. A mixed solution of water and fluorescein in methanol was delivered to the separation channel 7 s after the gradient program had been started. Then, the fluorescence intensity increased gradually with the increasing ratio of fluorescein, which showed that the gradient elution worked well. Under the gradient elution condition, the retention times of two coumarin dyes decreased with the gradient time. When the gradient time was 30 s, the analysis could be completed in 30 s, which was only half the time required compared to that required for an isocratic elution. Fluorescent derivatives of aliphatic amines were successfully separated within 110 s. The results show that the proposed system is promising for the analyses of complex biological samples.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Yanting
authors.initials: Y
authors.lastname: Song
authors.forename: Masao
authors.initials: M
authors.lastname: Noguchi
authors.forename: Katsuya
authors.initials: K
authors.lastname: Takatsuki
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Sekiguchi
authors.forename: Jun
authors.initials: J
authors.lastname: Mizuno
authors.forename: Takashi
authors.initials: T
authors.lastname: Funatsu
authors.forename: Shuichi
authors.initials: S
authors.lastname: Shoji
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsunoda
mesh_terms: D053801:Capillary Electrochromatography / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D003374:Coumarins / Q000032:analysis*; D017022:Flow Injection Analysis; D019793:Fluorescein / Q000032:analysis*; D005453:Fluorescence; D000432:Methanol; D013997:Time Factors; D014867:Water
chemical_list: D003374:Coumarins; D014867:Water; D019793:Fluorescein; D000432:Methanol