On-column detection of multiphoton-excited fluorescence in CE using hyphenated cylindrical-square capillaries

Authors

  • Youzhi Xu,

    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
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    • Both authors contributed equally to this work.

  • Sheng Chen,

    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
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    • Both authors contributed equally to this work.

  • Xiaojun Feng,

    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
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  • Wei Du,

    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
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  • Qingming Luo,

    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
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  • Bi-Feng Liu Professor

    Corresponding author
    1. The Key Laboratory of Biomedical Photonics of Ministry of Education- Hubei Bioinformatics and Molecular Imaging Key Laboratory-Division of Biomedical Photonics at Wuhan National Laboratory for Optoelectronics, Department of Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China
    • The Key Laboratory of Biomedical Photonics of Ministry of Education, Huazhong University of Science and Technology, Wuhan 430074, P. R. China Fax: +86-27-87792203
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Abstract

Multiphoton-excited fluorescence (MPEF) is a complementary and useful mode of LIF detection in CE with advantages of ultra-low mass detectability and spectral excitability, but it is currently quite limited by its end-column configuration. In this article, we demonstrate a novel strategy of on-column schemes that can greatly facilitate MPEF detection in CE. FITC-labeled amine species were used as the model samples for the evaluation and comparison of those detection scenarios. By using the square capillary instead of the conventional cylindrical one, the on-column MPEF could be readily achieved, with detection sensitivity of 0.72 μM that was comparable with the end-column mode. However, this strategy unfavorably reduced separation efficiency. The theoretical plate number on averaging all the sample peaks was significantly decreased from 283 000 to 19 000/m. To minimize such an influence, a short square capillary acting as an on-column MPEF detection cell was then mounted to a long cylindrical capillary responsible for the CE separation. Results indicated that both high separation efficiency (240 000/m) and better detectability (0.42 μM) were realized simultaneously by using this binary-capillary configuration. Quantitative analysis was performed under the optimized detector configuration and revealed a linear dynamic range of 2 orders of magnitude, with mass detection limit down to the mid-yottomole level.

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