STUDIES ON SOLID SURFACE-DELAY FLUORESCEN CE OF PIPEMIDIC ACID

The solid surface-delayed fluorescence of pipemidic acid was studied, The experiments indicate that inorganic salts, Bet (I), Mg(II), Ca(II) , Sr(II), Ba(II) and Zn(II), Cd(II), La(III) etc., can enhance greatly the luminescence signal. The pH value has an obvious effect and the m aximum luminescence signal can be obtained at pH 11.3. The measurement s of lifetime indicates that PPA decays in the diexponential in the so lid surfacer The lifetimes are 2. 79 ms and 1. 70 ms, respectively. Th e low temperature spectra of FPA were measured and the inorganic salts can also greatly increase low temperature luminescence signal. In thi s paper, the linear dynamic range of the analytical curve of PPA is 1 .8 ng-1800 ng/spot.