Analysis of fluorescence lifetime data for single rhodamine molecules in flowing sample streams

Journal Article · Fri Dec 31 23:00:00 EST 1993 · Analytical Chemistry (Washington); (United States)

DOI:https://doi.org/10.1021/ac00073a013· OSTI ID:7044917

Tellinghuisen, J ^[1]; Goodwin, P M; Ambrose, W P; Martin, J C; Keller, R A ^[2]

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1. Vanderbilt Univ., Nashville, TN (United States)
2. Los Alamos National Lab., NM (United States)

Fluorescence events of individual molecules of Rhodamine 110 dye in a stream of methanol occur as bursts of 5-300 photoelectrons when the dye molecules transit the volume interrogated by the pulsed excitation laser. The arrival times for these events, extracted by use of time-correlated single-photon counting techniques, are distributed exponentially over a approximately 10-ns time window gated to discriminate against prompt scattered light. Still, residual scattered light and solvent-impurity fluorescence contribute significantly to the recorded time distributions, which therefore must be analyzed as sums of an exponential decay and a background. Results obtained from two-parameter nonlinear least-squares fits are compared with maximum-likelihood estimates which ignore the background. In agreement with predictions, the relative error in the estimated decay rate exceeds the ideal N[sup [minus]1/2] limit that holds for N counts, free of background, recorded over an infinite time window. Data sets containing a small number of counts can exhibit problematic behavior, which can be understood from examination of contour plots of [chi][sup 2] as a function of the two least-squares parameters. The radiative lifetime of Rhodamine 110 in methanol is estimated to be 4.2 [+-] 0.2 ns. 28 refs., 15 figs.

• OSTI ID: 7044917
• Journal Information: Analytical Chemistry (Washington); (United States), Journal Name: Analytical Chemistry (Washington); (United States) Vol. 66:1; ISSN 0003-2700; ISSN ANCHAM
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400100* -- Analytical & Separations Chemistry
661300 -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALCOHOLS
AMINES
BACKGROUND NOISE
CARBOXYLIC ACIDS
COUNTING TECHNIQUES
DETECTION
DYES
ELECTROMAGNETIC RADIATION
EMISSION SPECTROSCOPY
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUID FLOW
FLUORESCENCE
FLUORESCENCE SPECTROSCOPY
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IRRADIATION
LASER RADIATION
LEAST SQUARE FIT
LIFETIME
LIGHT SCATTERING
LUMINESCENCE
MATHEMATICAL MODELS
MAXIMUM-LIKELIHOOD FIT
METHANOL
MOLECULES
NOISE
NUMERICAL SOLUTION
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOELECTRON COUNTING
PULSED IRRADIATION
RADIATIONS
REAGENTS
RHODAMINES
SCATTERING
SPECTROSCOPY