Department of Chemistry, Faculty of Engineering, Istanbul University , Avcilar 34320, Istanbul, Turkey.
J Agric Food Chem. 2013 Sep 4;61(35):8381-8. doi: 10.1021/jf402327x. Epub 2013 Aug 21.
A novel fiber optic sensor was developed for screening the total antioxidant capacity (TAC) based on the use of cupric-neocuproine (Cu(II)-Nc) immobilized onto a Nafion cation-exchange membrane with reflectance spectrometric measurement. The reflectance change associated with the formation of the highly colored Cu(I)-Nc chelate on the membrane as a result of reaction with antioxidants was measured at 530 nm by using a miniature reflectance spectrometer. The calibration graph of trolox (TR) was linear with a slope of 3.40 × 10(3) L mol(-1) mm(-1). The limit of detection (LOD) and limit of quantification (LOQ) for TR in the reflectometric cupric reducing antioxidant capacity (CUPRAC) method were found as 0.53 and 1.76 μM, respectively. The trolox equivalent antioxidant capacities (TEAC) of various antioxidant compounds using the proposed method were comparable to those of the main CUPRAC assay. This assay was validated through linearity, additivity, precision, and recovery. The developed reflectance sensor was used to screen the TAC of some commercial fruit juices and mice tissue homogenates without preliminary treatment. The method is rapid, inexpensive, versatile, and nonlaborious, uses stable reagents on the sensor, and enables the in situ estimation of antioxidant capacity of food extracts and biological samples.
一种新型光纤传感器是基于铜-邻菲啰啉（Cu(II)-Nc）固定在带有反射光谱测量的 Nafion 阳离子交换膜上而开发的，用于筛选总抗氧化能力（TAC）。通过使用微型反射光谱仪，在 530nm 处测量由于与抗氧化剂反应而在膜上形成高显色的 Cu(I)-Nc 螯合物引起的反射率变化。Trolox（TR）的校准曲线呈线性，斜率为 3.40×10(3)Lmol(-1)mm(-1)。在反射比色法铜还原抗氧化能力（CUPRAC）方法中，TR 的检测限（LOD）和定量限（LOQ）分别为 0.53 和 1.76μM。使用所提出的方法测定各种抗氧化化合物的 Trolox 等效抗氧化能力（TEAC）与主要的 CUPRAC 测定法相当。该测定法通过线性、加和性、精密度和回收率进行了验证。该开发的反射传感器用于筛选一些商业果汁和小鼠组织匀浆的 TAC，无需进行预处理。该方法快速、廉价、多功能且不费力，在传感器上使用稳定的试剂，并能够原位估计食品提取物和生物样品的抗氧化能力。
