Author(s): BOSSU, C. L.; FERREIRA, E. C.; CHAVES, F. S.; MENEZES, E. A.; NOGUEIRA, A. R. de A.

Summary: A flow injection system was proposed to evaluate tIle transient product of a colorimetric reaction between hydrolysable tannin and potassium iodate (KIO3) solution. The system optimization was accomplished by using statistical methods based on experimental design. Flow rate of KIO3 solution, sample volume, carrier flow rate, and reaction coil were lhe selected factors for evaluation. On screening step, complete factorial 2 potencial 4 was used and two levels for each selected factor were studied. For the optimization phase, a centered face composite design 2 pontecial 2 + star was employed to evaluate sample volume and flow rate of KIO3 solution, which were the factors identified in lhe screening phase as having more influence on the absorbance signal. After optimization, the proposed system was compared witll batch determination. Some characteristics, such a." analytical frequency, reagent consumption and chemical residues generation presented better results by lhe use of lhe proposed system if compared with batch method. The system presented good repeatability with standard deviation lower than 3%, for n= 10, linearity (R2=0.9974) fortannic acid standard, analytical frequency of 15 injections h -I and limit of quantification of 24 mg L-I of tannic acid. Good results were obtained when lhe proposed system was applied to hydrolysable tannin determination in Stryphnodendron barbatimão, Eucalyptus citriodora and Phyllanthus niruri samples of plants commonly used in popular medicine.

Publication year: 2006

Types of publication: Journal article

Unit: Embrapa Southeastern Livestock

Keywords: Flow injection analysis Experimental design, Hydrolysable tannin, Potassium iodate