Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok, 10110, Thailand.
Flow Innovation-Research for Science and Technology Laboratories (Firstlabs), Bangkok, Thailand.
Anal Bioanal Chem. 2022 Nov;414(27):7783-7791. doi: 10.1007/s00216-022-04312-z. Epub 2022 Sep 7.
This work presents a microfluidic paper-based analytical device (μPAD) for the determination of sucrose using the Benedict's test. An asymmetric dumbbell-shaped hydrophobic barrier was produced by rubber stamping the barrier pattern onto a laboratory filter paper. Hydrochloric acid and solution containing sucrose were successively deposited onto the sample reservoir of the μPAD attached to a glass slide. The device was placed in a plastic bag and dipped into boiling water for accelerating the hydrolysis of sucrose into the reducing sugars. Then the Benedict's reagent was added at the narrow straight channel connecting the two circular zones of the μPAD, which was replaced in the plastic bag and heated again for reduction of Cu(II) by the reducing sugars. Precipitate of brick-red copper(I) oxide was formed. The image of the μPAD was recorded by a smartphone. The ratio of the red to blue intensities gave linear correlation with the concentration of sucrose in the range of 0.5-10% w/v. The relative standard deviation of the measurement was less than 5% for 2 and 4% w/v sucrose (n = 10), with limit of determination, calculated using standard deviation of regression divided by slope of calibration, of 0.26% w/v sucrose. The method was successfully validated using the dinitrosalicylic acid method for sucrose measurement. Percent recoveries of sucrose were evaluated using ten sugarcane samples. The recoveries were in the range of 89 to 101%, demonstrating that there were no significant sample matrix effects on the quantification.
本工作提出了一种使用本尼迪克特（Benedict）试剂测定蔗糖的微流控纸基分析器件（μPAD）。通过将疏水障碍物图案用橡皮印章压印到实验室滤纸上来制备非对称哑铃形疏水障碍物。将盐酸和含有蔗糖的溶液相继沉积到附着在载玻片上的 μPAD 的样品储液器上。将该器件放入塑料袋中，并浸入沸水中以加速蔗糖水解成还原糖。然后，将本尼迪克特试剂添加到连接 μPAD 两个圆形区域的狭窄直通道中，将其重新放回塑料袋中并再次加热，使还原糖还原 Cu(II)。形成砖红色的氧化亚铜（I）沉淀物。使用智能手机记录 μPAD 的图像。红色与蓝色强度的比值与蔗糖浓度在 0.5-10% w/v 范围内呈线性相关。对于 2%和 4% w/v 的蔗糖（n = 10），测量的相对标准偏差小于 5%，根据回归标准差除以校准斜率计算，蔗糖的检出限为 0.26% w/v。使用二硝基水杨酸法成功验证了该方法对蔗糖的测定。使用十个甘蔗样品评估蔗糖的回收率。回收率在 89 到 101%的范围内，表明定量分析中不存在显著的样品基质效应。
