Micro Nano Bio-Fluids Group, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
Sci Rep. 2022 Aug 11;12(1):13657. doi: 10.1038/s41598-022-17851-3.
Milk adulteration is a common problem in developing countries, and it can lead to fatal diseases in humans. Despite several studies to identify different adulterants in milk samples, the effects of multiple adulterants remain unexplored. In this work, a three-dimensional (3D) paper-based microfluidic device is designed and fabricated to simultaneously detect multiple chemical adulterants in milk. This device comprises a top cover, a bottom cover, and a middle layer composed of transportation and a detection zone. By making cuts on the middle layer's support, the device's flow path is characterised by optimum and uniform velocity. For the first time, seven adulterants (urea, detergents, soap, starch, hydrogen peroxide, sodium-hydrogen-carbonate, and salt) are detected in the milk sample simultaneously with specificity evaluation and detailed color interference analysis. Only 1-2 mL of sample volume is required to detect 7 adulterants at one time. We have used only 10 [Formula: see text]L of the reagent's volume for the colorimetric reaction and found the results within a few seconds. Observation reveals that the limit of detection (LOD) of the adulterants lies in the range between [Formula: see text] (vol./vol.) to [Formula: see text] (vol./vol.) using the colorimetric detection technique. The unknown quantity of the added adulterants is measured using the calibration curves obtained from the experiments results. The repeatability and reproducibility of the process, sensitivity, and the linear range of detection of the calibration curves and the statistical study of the color intensity data are thoroughly analysed herein. In any resource-limited setting, this simple, portable, and user-friendly 3D microfluidic device is expected to be used for testing liquid foods before consumption.
牛奶掺假是发展中国家的一个常见问题，它可能导致人类致命疾病。尽管有几项研究旨在鉴定牛奶样本中的不同掺杂物，但对多种掺杂物的影响仍未得到探索。在这项工作中，设计并制造了一种三维（3D）纸基微流控装置，用于同时检测牛奶中的多种化学掺杂物。该装置由上盖、下盖和由输送和检测区组成的中间层组成。通过在中间层的支撑上进行切割，使装置的流道具有最佳和均匀的速度。这是第一次，同时进行了特异性评估和详细的颜色干扰分析，检测到了牛奶样本中的七种掺杂物（尿素、清洁剂、肥皂、淀粉、过氧化氢、碳酸氢钠和盐）。只需要 1-2 毫升的样品体积就可以同时检测 7 种掺杂物。我们只使用了 10 [Formula: see text]L 的试剂体积进行比色反应，并且在几秒钟内就得到了结果。观察结果表明，使用比色检测技术，掺杂物的检测限（LOD）在[Formula: see text]（体积/体积）至[Formula: see text]（体积/体积）之间。通过从实验结果获得的校准曲线来测量添加的未知掺杂物的数量。对该过程的重复性和再现性、灵敏度、校准曲线的检测线性范围以及颜色强度数据的统计研究进行了深入分析。在任何资源有限的环境中，这种简单、便携且用户友好的 3D 微流控装置有望在消费前用于测试液体食品。
