Institute for Innovative Learning, Mahidol University, Phuttamonthon 4 Road, Nakorn Pathom 73170, Thailand.
Anal Chim Acta. 2010 May 23;668(1):47-53. doi: 10.1016/j.aca.2010.01.021. Epub 2010 Jan 28.
This work presents a new sequential injection analysis (SIA) method and a module for simultaneous and real-time monitoring of three key parameters for the beverage industry, i.e., the sugar content (measured in Brix), color and dissolved CO(2). Detection of the light reflection at the liquid interface (the schlieren effect) of sucrose and water was utilized for sucrose content measurement. A near infrared LED (890+/-40 nm) was chosen as the light source to ensure that all the ingredients and dyes in soft drinks will not interfere by contributing light absorption. A linear calibration was obtained for sucrose over a wide concentration range (3.1-46.5 Brix). The same module can be used to monitor the color of the soft drink as well as the dissolved CO(2) during production. For measuring the color, the sample is segmented between air plugs to avoid dispersion. An RGB-LED was chosen as the light source in order to make this module applicable to a wide range of colored samples. The module also has a section where dissolved CO(2) is measured via vaporization of the gas from the liquid phase. Dissolved CO(2), in a flowing acceptor stream of water resulting in the change of the acceptor conductivity, is detected using an in-house capacitively coupled contactless conductivity detector (C(4)D). The module includes a vaporization unit that is also used to degas the carbonated drink, prior the measurements of sucrose and color within the same system. The method requires no chemicals and is therefore completely friendly to the environment.
本工作提出了一种新的顺序注射分析（SIA）方法和一个模块，用于同时实时监测饮料行业的三个关键参数，即糖含量（以白利糖度计）、颜色和溶解的 CO(2)。利用蔗糖和水的液体界面光反射（纹影效应）来检测蔗糖含量。选择近红外 LED（890+/-40nm）作为光源，以确保软饮料中的所有成分和染料不会因光吸收而产生干扰。在宽浓度范围内（3.1-46.5 白利糖度）获得了蔗糖的线性校准。相同的模块可用于在生产过程中监测软饮料的颜色和溶解的 CO(2)。为了测量颜色，将样品分段在空气塞之间以避免分散。选择 RGB-LED 作为光源，以使该模块适用于广泛的有色样品。该模块还有一个部分，通过从液相中蒸发气体来测量溶解的 CO(2)。通过在流动的水接受器流中蒸发气体，导致接受器电导率发生变化，从而检测到溶解的 CO(2)，使用内部电容耦合非接触式电导率检测器（C(4)D）。该模块包括一个蒸发单元，该单元也用于在同一系统内对碳酸饮料进行脱气，然后再进行蔗糖和颜色的测量。该方法不需要化学物质，因此对环境完全友好。
