The uncontrolled volume of sample has a significant influence on the outcome of the colorimetric detection method performed on paper-based microfluidic devices. In a reliable colorimetric assay, the results should be completely dependent on the concentration of analyte in the sample rather than its volume. However, this effect is usually overlooked in the development of paper-based microfluidic devices as a simple, inexpensive, portable and user-friendly medical diagnostic system. In this work, a volume-independent micro paper-based analytical device has been introduced in which the need for precise controlling of sample volume is eliminated. We have shown that the proposed device is only sensitive to the concentration of analyte (glucose) in the sample instead of its volume. We have also demonstrated that the proposed device addresses the reported problem of colour heterogeneity and is relatively insusceptible to the variation of reagents volume. An inexpensive smart phone camera is used for capturing the images and a portable 3D printed tool is designed to eliminate the environmental illuminations. To simulate the real condition, human plasma samples are used throughout the experiments.

不可控制的样本量对在纸基微流控设备上执行的比色检测方法的结果有重大影响。在可靠的比色测定中，结果应完全取决于样品中分析物的浓度而不是其体积。然而，在纸基微流控设备的开发中，这种效果通常被忽略，因为它是一种简单，廉价，便携和用户友好的医疗诊断系统。在这项工作中，已经引入了与体积无关的基于微型纸的分析设​​备，其中消除了对样品体积进行精确控制的需要。我们已经表明，所提出的设备仅对样品中分析物（葡萄糖）的浓度而不是其体积敏感。我们还证明了所提出的设备解决了所报告的颜色异质性问题，并且相对不易受试剂体积变化的影响。廉价的智能手机摄像头用于捕获图像，便携式3D打印工具设计用于消除环境照明。为了模拟真实情况，在整个实验过程中都使用了人类血浆样本。