Selective determination of theophylline in the presence of caffeine by sensitized luminescence of europium(III).
Theophylline was determined in a mixture with caffeine by room-temperature luminescence. The excitation energy absorbed by the theophylline was transferred to europium(III), which then emitted its characteristic luminescence. The enhanced luminescence emission intensity was quantitatively related to theophylline concentration without interference from caffeine or emission from the sample matrix. A mechanism explaining the observed selectivity is presented. Possible analytical use of the energy-transfer approach for the determination of similarly structured compounds is discussed.
Perry
L M
LM
Department of Chemistry, University of Florida, Gainesville, FL 32611, U.S.A.
Winefordner
J D
JD