Fig. 3

Fluorescence spectra of SIL at increasing concentrations in the range of 0.2–36.4 μM at 460 nm after excitation of 330 nm in pH 6.0 phosphate buffer (the concentration range: 0.2 (b)–1.0 (f) μM (b); 1.0 (g)–36.4 (p) μM (a)). Fluorescence spectrum of blank solution ((a) and (f)) containing methanol:water: pH 6.0 phosphate buffer). The calibration curve of SIL obtained by spectrofluorimetry (c) in pH 6.0 phosphate buffer