FIA-FAAS method for tannin determination based on a precipitation reaction with hemoglobin

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Author(s):	Edilene C. Ferreira ; Gilberto B. Souza ; Ana Rita A. Nogueira ^[3] Total Authors: 3
Document type:	Journal article
Source:	Journal of the Brazilian Chemical Society; v. 14, n. 2, p. 329-333, 2003-04-00.
Abstract
A flow system, coupled with flame atomic absorption spectrometry (FIA-FAAS), was developed for tannin determination in pigeon pea samples, exploring the precipitation reaction between tannins and proteins. Sample extracts obtained by sonication with a 50% (v/v) methanol solution were introduced into the system and induced to react with a hemoglobin solution. The precipitate produced was retained on a filter located in the analytical flow. A reversed flow of 1% (w/v) sodium dodecyl sulfate solution was used for solubilization of the precipitate from the filter and to conduct the tannin-hemoglobin complex to the FAAS, to quantify the iron ions present in the hemoglobin structure. A tannic acid solution was used to prepare the analytical curve. The proposed method allowed determination of 30 samples per hour, a standard deviation of 9.7% (n=10), and a quantification limit of 0.27 mg L-1 for tannic acid. (AU)

FAPESP's process:	98/10814-3 - Preparation of agronomic samples and multi-elementary determination by induced plasma atomic emission spectrometry
Grantee:	Joaquim de Araújo Nóbrega
Support Opportunities:	Research Projects - Thematic Grants