Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia.
School of Chemical Engineering , The University of Adelaide , Adelaide , South Australia 5005 , Australia.
Anal Chem. 2019 Apr 16;91(8):5011-5020. doi: 10.1021/acs.analchem.8b04963. Epub 2019 Mar 1.
Anthropogenic copper pollution of environmental waters from sources such as acid mine drainage, antifouling paints, and industrial waste discharge is a major threat to our environment and human health. This study presents an optical sensing system that combines self-assembled glutaraldehyde-cross-linked double-layered polyethylenimine (PEI-GA-PEI)-modified nanoporous anodic alumina (NAA) interferometers with reflectometric interference spectroscopy (RIfS) for label-free, selective monitoring of ionic copper in environmental waters. Calibration of the sensing system with analytical solutions of copper shows a linear working range between 1 and 100 mg L, and a low limit of detection of 0.007 ± 0.001 mg L (i.e., ∼0.007 ppm). Changes in the effective optical thickness (ΔOT) of PEI-GA-PEI-functionalized NAA interferometers are monitored in real-time by RIfS, and correlated with the amount of ionic copper present in aqueous solutions. The system performance is validated through X-ray photoelectron spectroscopy (XPS) and the spatial distribution of copper within the nanoporous films is characterized by time-of-flight-secondary ion mass spectroscopy (TOF-SIMS). The specificity and chemical selectivity of the PEI-GA-PEI-NAA sensor to Cu ions is verified by screening six different metal ion solutions containing potentially interfering ions such as Al, Cd, Fe, Pb, Ni, and Zn. Finally, the performance of the PEI-GA-PEI-NAA sensor for real-life applications is demonstrated using legacy acid mine drainage liquid and tap water for qualitative and quantitative detection of copper ions. This study provides new opportunities to develop portable, cost-competitive, and ultrasensitive sensing systems for real-life environmental applications.
人为造成的环境水中铜污染来自于各种来源，如酸性矿山排水、防污涂料和工业废物排放等，这对我们的环境和人类健康构成了重大威胁。本研究提出了一种光学传感系统，该系统结合了自组装戊二醛交联双层聚乙烯亚胺（PEI-GA-PEI）修饰的纳米多孔阳极氧化铝（NAA）干涉仪与反射干涉光谱（RIfS），用于对环境水中的离子铜进行无标记、选择性监测。该传感系统用铜的分析溶液进行校准，结果表明在 1 至 100 mg L 之间具有线性工作范围，检测下限低至 0.007 ± 0.001 mg L（即约 0.007 ppm）。通过 RIfS 实时监测 PEI-GA-PEI 功能化 NAA 干涉仪的有效光学厚度（ΔOT）的变化，并与水溶液中存在的离子铜量相关联。通过 X 射线光电子能谱（XPS）验证了系统性能，并通过飞行时间二次离子质谱（TOF-SIMS）对纳米多孔膜内的铜空间分布进行了表征。通过筛选含有潜在干扰离子（如 Al、Cd、Fe、Pb、Ni 和 Zn）的六种不同金属离子溶液，验证了 PEI-GA-PEI-NAA 传感器对 Cu 离子的特异性和化学选择性。最后，使用传统的酸性矿山排水液体和自来水，对 PEI-GA-PEI-NAA 传感器进行了定性和定量检测铜离子的实际应用性能验证。本研究为开发用于实际环境应用的便携式、具有成本竞争力和超高灵敏度的传感系统提供了新的机会。
