Determination of Reducing Sugar using MOF-Cu(II) as
Solid Reagent
M. F. Belian, A. A. Alves, P. A. B. da Silva, A. F. Lavorante
Laboratório de Análise Química, Inorgânica e Sensores - LAQIS, Departamento de Química,
Universidade Federal Rural de Pernambuco, PE, Brazil
Keywords: reducing sugar, metal-organic frameworks, solid reagent.
The determination of reducing sugars is frequently performed in the wine industry as
important parameter to control during its production, beyond to follow the fermentation
process. Reducing sugars determination in wines is also used for routine quality control and
for checking if the wine meets the legal or commercial reducing sugars content required for a
certain wine type [1]. For this determination, the Lane-Eynon method [2] involving reducing
sugar titration by Cu (II) under alkaline medium and high temperature (~100 0C) is often used.
In current work is report the synthesis and characterization of metal-organic framework
(MOF), containing copper (II) and 4,4’-dipyridyl, that acts as solid reagent in reducing sugars
determination. The MOF-Cu (II) presented as a blue solid and the reaction yield was 85%.
Elemental analysis and infrared spectroscopy data suggest the proposed formulae - [Cu(4,4‘dipy)(H2O)2]n. The reaction of MOF-Cu(II) and reducing sugar (glucose or fructose standard
solutions – 100 g/L) result in orange solution, that was characterized from the absorption
spectroscopy showing an maximum at 380 nm (Figure 1). MOF-Cu(II) after reaction,
presented changing related to color and structure, in this last case was observed by scanning
electronic microscopy, shown in Figure 1.
3,0
2,5
MOF-Cu(II) + reducing sugar (100g/L)
Absorbance
2,0
(i)
1,5
1,0
380 nm
0,5
0,0
300
(ii)
400
500
wavelength (nm)
Figure 1. (A) Scanning electronic microscopy (SEM) before (i) and after (ii) of the reaction
MOF-Cu(II) with reducing sugar; and (B) absorption spectrum of resulting solution.
Work supported by FACEPE and CNPq.
[1] A. N. Araújo, J.L.F.C. Lima, A.O.S.S. Rangel, M.A. Segundo, Talanta 52, 59-62 (2000).
[2] F. Schneider (Ed.), Sugar Analysis, Official and tentative methods recommended by the
International Commission for Uniform Methods of Sugar Analysis (ICUMSA). ICUMSA,
Peterborough, 1979, pp. 41-73.
e-mail: [email protected]