Single-Molecule Detection Limits in Levitated Microdroplets

William B. Whitten, J. Michael Ramsey, Stephen Arnold, Burt V. Bronk

Research output: Contribution to journalArticlepeer-review


Laser-excited fluorescence from electrodynamically levitated microdroplets Is used to detect small numbers of rhodamlne-6G molecules. The small sample volume, typically a few plcollters reduces the background due to solvent and Impurity Raman and fluorescence emission. With 514.5-nm excitation from an argon Ion laser, as few as 12 molecules have been detected In glycerol-water droplets. Our present detection limit, due to variations In the Impurity concentration In the blanks, corresponds to a slgnal-to-nolse ratio of 3 for a single molecule of rhodamlne-6G contained In a 1-pL volume (dro plet diameter of ≃12 µm).

Original languageEnglish (US)
Pages (from-to)1027-1031
Number of pages5
JournalAnalytical Chemistry
Issue number10
StatePublished - Jan 1991

ASJC Scopus subject areas

  • Analytical Chemistry


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