Araújo A N, Lima J L, Rangel A O, Segundo M A
CEQUP/Departamento de Química-Física, Faculdade de Farmácia, R. Aníbal Cunha 164, 4050 Porto, Portugal.
Talanta. 2000 May 31;52(1):59-66.
A sequential injection system for the spectrophotometric determination of reducing sugars in wines is described. The methodology is based on the formation of a coloured complex produced by the reaction of copper (I) with 2,9-dimethyl-1,10-phenanthroline (neocuproine), after reduction of copper (II) to copper (I) by reducing sugars. In the present SI system, a dialysis unit was incorporated not only to allow the sample dilution, but also to minimise the interference of some coloured compounds. In this way, direct sample introduction into the system was possible, without any previous treatment of the wine samples. The proposed method can be applied to the determination of reducing sugars in two concentration ranges: from 2 to 25 g l(-1) (table wines) and from 20 to 140 g l(-1) (Port wines). To perform determinations in these two ranges, the manifold configuration remained the same; just a few operational parameters were changed in the controlling software. A sampling-rate of 14-18 samples per hour was obtained with good repeatability for ten consecutive injections of wine samples (relative standard deviations (RSD) <2.1%). The results obtained from 19 wine samples were comparable to those obtained by the reference method.
本文描述了一种用于分光光度法测定葡萄酒中还原糖的顺序注射系统。该方法基于还原糖将铜（II）还原为铜（I）后，铜（I）与2,9 - 二甲基 - 1,10 - 菲咯啉（新铜试剂）反应生成有色络合物。在本顺序注射系统中，引入了一个透析单元，不仅用于样品稀释，还用于减少某些有色化合物的干扰。通过这种方式，可以直接将样品引入系统，而无需对葡萄酒样品进行任何预处理。所提出的方法可用于测定两个浓度范围内的还原糖：2至25 g l⁻¹（餐酒）和20至140 g l⁻¹（波特酒）。为了在这两个范围内进行测定，流路配置保持不变；只是在控制软件中更改了一些操作参数。连续十次注射葡萄酒样品时，获得了每小时14 - 18个样品的采样率，具有良好的重复性（相对标准偏差（RSD）<2.1%）。从19个葡萄酒样品中获得的结果与参考方法获得的结果相当。
