Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Laboratorio de Biofisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Food Chem. 2017 Apr 15;221:1062-1068. doi: 10.1016/j.foodchem.2016.11.055. Epub 2016 Nov 16.
Absorbance detection in food microdevices has not been thoroughly used due to low levels of sensitivity in measurements. Thus, it is necessary to develop microfluidic methods for improving photometric detection. For this purpose, a simple coupled-optical-fiber-polydimethylsiloxane (PDMS) microdevice was developed, to quantify polyphenols content in white wine employing the Folin-Ciocalteu reaction method. A 6V and 10W halogen lamp with an optical path length of 7mm between optical fibers, which were placed into the microchip, using guides at the outlet of the flow, increased the level of sensitivity during detection. The linear range was from 0.03mmol/L to 0.18mmol/L. Thus, the corresponding equation was: Abs=4.00(±0.16) [tannic acid]+0.17(±0.017). Intra-laboratory repeatability and reproducibility percentages were 2.95% and 6.84%, respectively. Such results were compared to those obtained from applying the conventional flow-injection analysis method, based on the same type of reaction. The relative error between methods was less than 13%.
由于测量时灵敏度低，食品微器件中的吸光度检测并未得到充分应用。因此，有必要开发微流控方法来提高光度检测的灵敏度。为此，开发了一种简单的光纤-聚二甲基硅氧烷（PDMS）耦合微器件，采用福林-考尔法测定白葡萄酒中多酚的含量。在微芯片中放置了一个带有 7mm 光纤光路长度的 6V 和 10W 卤素灯，通过出口处的导槽将光纤放入微芯片中，从而提高了检测时的灵敏度。线性范围为 0.03mmol/L 至 0.18mmol/L。因此，相应的方程为：Abs=4.00(±0.16) [鞣酸]+0.17(±0.017)。实验室内部重复性和再现性的百分比分别为 2.95%和 6.84%。将这些结果与基于相同反应类型的常规流动注射分析方法获得的结果进行了比较。两种方法之间的相对误差小于 13%。
