19 October 1983 An Approach To Single Molecule Detection By Laser-Induced Fluorescence
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Abstract
A sheath flow cuvette was evaluated in laser-induced fluorescence determination of aqueous rhodamine 6G. A detection limit of 18 attograms was obtained within a one-second signal integration time. The concentration detection limit was 8.9 x 10-14 mole per liter. An average of one-half rhodamine 6G molecule was present within the 11 pL excitation volume. However, dUring the signal integration time a total of 22,000 analyte molecules passed through the excitation region in a 0.42 microliter volume. The biomedical technique of flow cytometry has been used to study the fluorescence and light scatter properties of biological cells and cellular components.1 The hydrodynamic focusing property of the sheath flow cuvette employed in flow cytometry provides a well designed flow chamber for laser-induced fluorescence analysis of small volume samples. The sheath flow cuvette has been applied as a laser-induced fluorescence detector in high performance liquid chromatography and flow injection analysis.2-4 A tightly focused laser beam was used in those experiments to define an excitation volume of several nanoliters. In the present report, the performance of the sheath flow cuvette is considered for fluorescence analysis in excitation volumes of several picoliters.5 The sample cell is shown in Figure 1.
© (1983) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Norman J. Dovichi, John C. Martin, James H. Jett, Mitchell Trkula, Richard A. Keller, "An Approach To Single Molecule Detection By Laser-Induced Fluorescence", Proc. SPIE 0426, Laser-Based Ultrasensitive Spectroscopy and Detection V, (19 October 1983); doi: 10.1117/12.936239; https://doi.org/10.1117/12.936239
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