Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1/3, 119991 Moscow, Russia.
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Avenue, 31, 119991 Moscow, Russia.
Sensors (Basel). 2022 Apr 9;22(8):2893. doi: 10.3390/s22082893.
Microfluidic paper-based analytical devices (µPADs) represent one of the promising green analytical strategies for low-cost and simple determination of various analytes. The actual task is the development of such devices for quantitation of antioxidants, e.g., flavonoids. In this paper, possibilities of a novel three-reagent µPAD including silver nitrate, 4-nitrophenyldiazonium tetrafluoroborate, and iron(III) chloride as reagents are assessed with respect to the determination of dihydroquercetin. It is shown that all the three reagents produce different colorimetric responses that can be detected by a mini-spectrophotometer-monitor calibrator or by a smartphone. The method is applicable to direct measuring high contents of dihydroquercetin (the linearity range is 0.026-1 mg mL, and the limit of detection is 7.7 µg mL), which is favorable for many dietary supplements. The analysis of a food supplement was possible with the relative standard deviations of 9-26%, which is satisfactory for quantitative and semiquantitative determinations. It was found that plotting a calibration graph in 3D space of the three reagents' responses allows us to distinguish dihydroquercetin from its close structural analogue, quercetin.
微流控纸基分析器件 (µPADs) 代表了一种有前途的绿色分析策略，可用于低成本、简单地测定各种分析物。实际任务是开发此类设备来定量测定抗氧化剂，例如黄酮类化合物。本文评估了包括硝酸银、4-硝基苯重氮四氟硼酸盐和三氯化铁在内的新型三试剂 µPAD 用于测定二氢槲皮素的可能性。结果表明，所有三种试剂都产生了不同的比色响应，可通过微型分光光度计-监测校准器或智能手机进行检测。该方法适用于直接测定二氢槲皮素的高含量（线性范围为 0.026-1mg/mL，检测限为 7.7µg/mL），这有利于许多膳食补充剂。对一种膳食补充剂的分析结果具有 9-26%的相对标准偏差，这对于定量和半定量测定是令人满意的。结果发现，绘制三个试剂响应的三维空间校准图可以帮助我们区分二氢槲皮素与其结构类似物槲皮素。
