[54] PHASE FLUOROMETRY USING A
MODULATED ELECTROLUMINESCENT
LAMP AS A LIGHT SOURCE
[75] Inventors: Klaus W. Berndt, Baltimore; Joseph R. Lakowicz, Columbia, both of Md.
[73] Assignee: The University of Maryland School of Medicine
[21] Appl. No.: 755,232
[22] Filed: Sep. 5,1991
[51] Int. CI.5 G01J 1/58
[52] U.S. CI 250/458.1; 250/459.1
[58] Field of Search 250/458.1, 459.1;
356/318, 417; 315/169.3
[56] References Cited
U.S. PATENT DOCUMENTS
4,633,141 12/1986 Weber 315/169.3
4,705,952 11/1987 Lindmayer 250/483.1
4,778,593 10/1988 Yamashita et al 209/3.1
4,877,965 10/1989 Dandliker et al 250/458.1
4,889,690 12/1989 Oritz et al 250/458.1
4,895,156 1/1990 Schulze 128/634
5,030,420 7/1991 Bacon et al 422/82.07
OTHER PUBLICATIONS Wolfbeis et al "A new group of Fluorescent pH-Indica
[ii] Patent Number: 5,281,825 [45] Date of Patent: Jan. 25,1994
tors for an extended pH -range", Fresenius Z. Anal Chem (1987), V. 327 pp. 347-350. Moreno et al., "... pH Sensitive Optical Fiber Sensor . .. "; J. Mole Struc. 143 (1986) p. 553. Guthrie et al. "Solid-State . . . Optical Fiber Chem Sensor"; Talanta, 35, 2 (1988) p. 157. Ohkuma et al., "Luminescence Probe... of Intralysosomal ph . .. " Proc. Natl. Acad. Sci (75) 1978, p. 3327. Lippitsh et al., ". . . Oxygen Sensor with the Fluorescence Decay Time as the Inform. Carriers", Anal. Chim Acta, 205 (1988) 1-6.
Berndt et al "Phase-modulation Fluorometry using a.. . laser diode light source" Rev. Sci. Instrum. 61(7) p. 1816 (1990).
Primary Examiner—Paul M. Dzierzynski
Assistant Examiner—Richard Hanig
Attorney, Agent, or Firm—Sughrue, Mion, Zinn,
Macpeak & Seas
[57] ABSTRACT
A method and apparatus for using a square wave- or sinewave-driven electroluminescent lamp (ELL) as a source of periodically pulsed excitation light for a luminescent molecule, wherein changes in decay time, phase angle and/or modulation of the emitted luminescence are detected as parameters that correspond to changes in luminescence lifetimes.
55 Claims, 4 Drawing Sheets
