Analytical Sciences

Reversed-phase Chromatography in an Extended Nanospace: Separating Amino Acids in Short and Long Nanochannels

Adelina SMIRNOVA, Hisashi SHIMIZU, Kazuma MAWATARI, and Takehiko KITAMORI

Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113–8656, Japan

Micro- and nanofluidics has attracted much attention, particularly concerning single-cell analysis when small amounts of liquids are examined. In present work we successfully fabricated extended-nano channels that were more narrow and shorter (2 mm) as well as wider and longer (10 mm), and accomplished a reversed-phase HPLC separation of labeled amino acids on these channels after octadecylsilylation (ODS). The separation performance characteristics were compared for both types of nano spaces. At an equal amount of pressure, the longer extended-nano channels showed permeability that was one-order higher (K = 47 × 10⁻¹⁴ m²) and separation impedance (E = 13) that was one-order lower than that of the shorter version. Also, the separation plate number for the longer channel was 4000 with a plate height of 2.5 μm. Both channels have advantages for use in single-cell analysis. The longer channel can be applied for the separation of macromolecules (proteomics), while the short version is more applicable to small molecules (amino acids).

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