Diffraction-based label-free photothermal detector for separation analyses in a nanocapillary

Yoshiyuki Tsuyama; Kyojiro Morikawa; Kazuma Mawatari

doi:10.1016/j.chroma.2021.462214

Diffraction-based label-free photothermal detector for separation analyses in a nanocapillary

J Chromatogr A. 2021 Jul 5:1648:462214. doi: 10.1016/j.chroma.2021.462214. Epub 2021 May 2.

Authors

Yoshiyuki Tsuyama¹, Kyojiro Morikawa², Kazuma Mawatari³

Affiliations

¹ Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.
² Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.
³ Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan; Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan. Electronic address: kmawatari@g.ecc.u-tokyo.ac.jp.

PMID: 34004365
DOI: 10.1016/j.chroma.2021.462214

Abstract

Miniaturization of column diameter in liquid chromatography is one of the major trends in separation sciences toward single-cell proteomics and metabolomics. Micro/nanoscale open tubular (OT) capillaries are promising tools for efficient separation analyses of the ultra-small volume of samples. However, highly sensitive and label-free on-column detection is still challenging for such ultra-small capillaries. In this study, we developed a photothermal detector using optical diffraction phenomena by a single nanocapillary. Our detection method realized concentration determination of unlabeled sample solutions in a nanocapillary with 460 nm inner diameter. The calculated limit of detection was 0.12 µM, which corresponds to 16 molecules in a detection volume of 0.23 fL. Furthermore, normal-phase chromatography was performed on a 12 cm long nanocapillary, and femtoliter sample injection, efficient separation, and label-free detection of dye molecules were demonstrated. Our photothermal detector will be widely used as a universal tool for chemical/biological analyses using capillaries with micro/nanoscale diameters.

Keywords: Label-free detection; Nanocapillary; Normal-phase chromatography; Optical diffraction; Photothermal effect.

MeSH terms

Chromatography, Liquid / methods*
Limit of Detection
Nanotechnology
Proteomics