Laser-induced fluorescence of flowing samples as an approach to single-molecule detection in liquids
A flow cytometer system was used to detect aqueous rhodamine 6G by laser-induced fluorescence. Best results were obtained with careful spectral and spatial filtering. At the detection limit, the probability of a rhodamine 6G molecule being present in the detector's probed volume of 11 pL is about 0.6 . With a flow rate of 0.42 ..mu..L/s, a detection limit of 8.9 x 10/sup -14/ M was obtained for a 1-s time constant. At the detection limit, 18 ag or 22,000 molecules of rhodamine 6G flowed through the probed volume during the signal integration period. Signal linearity extends over greater than 5 orders of magnitude limited only by saturation of the detection electronics at high concentration. The results presented here allow a projection to single-molecule detection with reasonable improvements to the apparatus. 25 references, 5 figures, 7 tables.
- Research Organization:
- Los Alamos National Lab., NM
- OSTI ID:
- 6140399
- Journal Information:
- Anal. Chem.; (United States), Vol. 56:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CELL FLOW SYSTEMS
CALIBRATION
RHODAMINES
FLUORESCENCE SPECTROSCOPY
AQUEOUS SOLUTIONS
EXPERIMENTAL DATA
FLUORESCENCE
LASERS
MOLECULES
QUANTITATIVE CHEMICAL ANALYSIS
AMINES
CARBOXYLIC ACIDS
CHEMICAL ANALYSIS
DATA
DISPERSIONS
DYES
EMISSION SPECTROSCOPY
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
LUMINESCENCE
MIXTURES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
REAGENTS
SOLUTIONS
SPECTROSCOPY
400104* - Spectral Procedures- (-1987)