Automated Spectrophotometric Multi-Pumping Flow System for the Determination of Total Iron in Wine

Abstract

A new automated system based on a multi-pumping flow system (MPFS) for the spectrophotometric determination of total iron in various wine samples is presented. This analytical protocol is based on the complex formation between Fe (II) and 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP). The addition of ascorbic acid allows the determination of total iron by reducing the Fe (III) present in the samples to Fe (II). Several physical and chemical parameters, including the mixing coil length, the sample volume, the chromogenic reagent concentration, the pH, and the ascorbic acid concentration have been characterized in order to optimize the analytical conditions. The limits of detection and quantification were 34 µg L⁻¹ and 114 µg L⁻¹ respectively. The developed procedure requires minimal sample preparation.

Keywords:

• Ascorbic acid
• 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP)
• flow injection analysis
• multi-pumping flow system
• total iron
• wines

Additional information

Funding

This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO Project CTQ2016-77155-R) and by FEDER. Kaewta Danchana acknowledges the financial support from the Conselleria d’Innovació, Recerca I Turisme of the Govern de les Illes Balears and of the Fons Social Europea (FPI/1867/2016).