Add time:08/07/2019         Source:sciencedirect.com

A critical study of the use of the Fe(III)/3-hydroxy-4-nitroso-2,7-naphthalenedisulfonic acid (NRS) complexes on the quantification of the polyphenols content in aqueous extracts of plants, expressed as pyrogallic acid, [PA], is presented. The reaction used is based on the reduction of Fe(III) to Fe(II) by [PA] in the presence of NRS in a buffered medium (Tris; pH 8.0) with formation of Fe(II)/NRS complexes. A calibration curve of absorbance (at 730 nm) vs. [PA] is linear (r = 0.998; n = 7) from 1.0 to 7.0 μmol L−1 [PA]. LD and RSD were 0.5 μmol L−1 and 2.5% (6.0 μmol L−1 [PA], n = 10), respectively. The influence of pH, type of buffer solution and interfering species possibly present in the samples were evaluated. Aqueous extracts of twelve medicinal plants used in the Brazilian folk medicine were analysed by using both Fe(III)/NRS complexes and the Folin–Ciocalteu reagent.

We also recommend Trading Suppliers and Manufacturers of 2,7-Naphthalenedisulfonic acid disodium salt (cas 1655-35-2). Pls Click Website Link as below: cas 1655-35-2 suppliers