Aryal Prakash, Brack Eric, Alexander Todd, Henry Charles S
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.
U.S. Army Combat Capabilities Development Command (DEVCOM)─Soldier Center, 10 General Greene Avenue, Natick, Massachusetts 01760, United States.
Anal Chem. 2023 Apr 4;95(13):5820-5827. doi: 10.1021/acs.analchem.3c00378. Epub 2023 Mar 23.
Human exposure to heavy metals is a concerning global problem because of its detrimental effect on our health and ecosystem. Assessing the levels of these metals is cost- and labor-intensive and nonuser friendly because current analysis approaches typically rely on heavy instrumentations like inductively coupled plasma-mass spectrometry, which is only possible in centralized labs. Hence, simple economical detection methods are in high demand in developing countries and areas with insufficient infrastructure, professional experts, and appropriate environmental treatment. Several microfluidic paper-based analytical devices have been reported as promising alternatives to conventional testing methods for on-site heavy metal detection. Paper-based microfluidics are advantageous because of their simple fabrication, biodegradability, low cost, and ability to operate without pumps. However, typical assay times for current platforms are slow, and they typically rely on pipetting a fixed volume into the assay cards. This adds complexity in actual field scenarios. Here, we report a novel, inexpensive, and straightforward capillary-driven microfluidic device combined with paper for rapid and user-friendly detection of Ni(II), Cu(II), and Fe(III) in water. A colorimetric approach was adopted to quantify these metals. The device was able to produce a homogeneous color signal within 8 s of sample insertion. The limit of detection and limit of quantification were calculated to be 2 and 6.67 ppm for nickel, 0.3 and 1 ppm for Cu, and 1.1 and 3.67 ppm for Fe, respectively. The majority (>90%) of the collected samples showed recovery in the 80-110% range with acceptable accuracy and precision (<15% RSD) for a colorimetric device. This technique can be beneficial for rapidly assessing heavy metal exposure in drinking and surface water at drastically reduced assay time and is the first example of capillary flow-driven microfluidic devices as a transport medium for heavy metal detection.
由于重金属对人类健康和生态系统具有有害影响，人类接触重金属是一个令人担忧的全球性问题。评估这些金属的含量既耗费成本又需要大量人力，而且对用户不友好，因为目前的分析方法通常依赖于电感耦合等离子体质谱仪等大型仪器，而这只有在集中化实验室中才有可能实现。因此，在基础设施不足、专业专家匮乏以及缺乏适当环境处理措施的发展中国家和地区，对简单经济的检测方法有很高的需求。已有报道称，几种基于微流控纸的分析装置有望成为现场重金属检测的传统测试方法的替代方案。基于纸的微流控技术具有优势，因为其制造简单、可生物降解、成本低且无需泵即可操作。然而，当前平台的典型检测时间较慢，并且它们通常依赖于将固定体积的液体移液到检测卡中。这在实际现场场景中增加了复杂性。在此，我们报告了一种新型、廉价且简单的毛细管驱动微流控装置，该装置结合了纸，用于快速且用户友好地检测水中的镍（II）、铜（II）和铁（III）。采用比色法对这些金属进行定量。该装置能够在样品插入后8秒内产生均匀的颜色信号。计算得出镍的检测限和定量限分别为2 ppm和6.67 ppm，铜为0.3 ppm和1 ppm，铁为1.1 ppm和3.67 ppm。对于比色装置而言，所采集的大多数样品（>90%）的回收率在80 - 110%范围内，具有可接受的准确度和精密度（<15%相对标准偏差）。该技术有助于在大幅缩短检测时间的情况下快速评估饮用水和地表水中的重金属暴露情况，并且是毛细管流动驱动微流控装置作为重金属检测传输介质的首个实例。
