Leposava Pavun,1,* Daniela Ðikanović,2 Predrag Ðurđević,3 Milena Jelikić Stankov,4 Dušan Malešev1 and Andrija Ćirić3
1 Department of Physical Chemistry, Faculty of Pharmacy, University of Belgrade,
Serbia, Vojvode Stepe 450, Beograd, Serbia
2 Institute for Multidisciplinary Studies, University of Belgrade,
Despota Stefana 142, Belgrade, Serbia
3 Department of Chemistry, Faculty of Science, University of Kragujevac,
Serbia, Radoja Domanovića 12, Kragujevac, Serbia
4 Department of Analytical Chemistry, Faculty of Pharmacy, University of
Belgrade,
Serbia, Vojvode Stepe 450, Beograd, Serbia
* Corresponding author: leposava.pavun@pharmacy.bg.ac.rs
Abstract
Morin is a flavonol antioxidant. In ethanol – water mixtures (70 wt % of
ethanol) it reacts with Al3+ to give Al(Morin)2
in the pH range 3–6. The conditional stability constant of this complex at 298 K
was found to be log β2 = 16.96 ± 0.02
at pH 4.40. The complex shows strong fluorescence emission at 500 nm upon
excitation at 410 nm. The fluorescence intensity
is pH dependent with maximum emission at pH 4.40. Since the complexation
reaction enhances the fluorescence
of morin, this property was used for the determination of morin in human serum.
A linear dependence of the intensity
of fluorescence of the complex on the concentration of morin was obtained in
morin concentration range from 1.5–30.5
ng mL–1, relative standard error of measurements was 1.4 %. The LOD was 0.02 ng
mL–1 while LOQ was 1.0 ng mL–1.
Serum concentration of morin was also determined using HPLC as a reference
method. A C-18 Hypersil Gold AQ column
was used with acetonitrile – 0.1% v/v phosphoric acid (30:70% v/v) as the mobile
phase at 1.0 mL min–1 flow rate
and UV detection at 250 nm. Acceptable relative standard errors (less than 5%)
between determinations obtained by
the two methods indicate that the fluorescence method is reliable.
Keywords: Morin, aluminium, determination, spectrofluorimetry, serum