Spectrophotometric Study of Luminol in Dimethyl Sulfoxide–Potassium Hydroxide |
| |
Authors: | Marilena Vasilescu Titus Constantinescu Mariana Voicescu Helge Lemmetyinen Elina Vuorimaa |
| |
Institution: | (1) Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 77208 Bucharest, Romania;(2) Institute of Materials Chemistry, Tampere University of Technology, 33101 Tampere, Finland |
| |
Abstract: | The spectrophotometric study of luminol (LH2) in dimethyl sulfoxide (DMSO), DMSO-water solutions, and alkaline DMSO and DMSO-water solutions has been done, focusing on the effect of the KOH additon on LH2 absorption and fluorescence properties. The absorption spectra indicate an acid-base equilibrium, and the luminol dianion (L2–) formation at 3 × 10–4 – 2.4 × 10–3
M KOH. The decrease of the fluorescence intensity and the variation of the excitation spectra of LH2-DMSO-KOH solutions with KOH concentration have been similarly explained. The acid-base process is reversible. The addition of HCl to the solution with 3.0 × 10–3 M KOH leads to an increase of the fluorescence intensity to its highest value, observed in pure DMSO. The addition of HCl to the LH2-DMSO solution leads to the decrease of the fluorescence intensity as a result of the LH+
3 cation formation. In LH2-DMSO-water, the fluorescence band is shifted from 405 nm to 424 nm and increased in the intensity. In the presence of KOH (in LH2-DMSO-water-KOH solution) a new band appears, with the maximum at 485 nm and the band at 405 nm decreased. The changes in fluorescence lifetimes also evidence the different chemical species formed. |
| |
Keywords: | Luminol fluorescence alkaline dimethyl sulfoxide luminol fluorescence lifetime |
本文献已被 SpringerLink 等数据库收录! |
|