Li Dai-En, Lin Che-Hsin
Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-sen University Kaohsiung, 804 Taiwan
RSC Adv. 2018 Apr 30;8(29):16139-16145. doi: 10.1039/c8ra02468e. eCollection 2018 Apr 27.
This study presents a novel microfluidic chip that can achieve on-demand gold nanoparticle (AuNP) synthesis using atmospheric pressure helium plasma and on-site mercury ion detection. Instead of using conventional chemical reaction methods, this chip uses helium plasma as the reducing agent to reduce gold ions and to synthesize AuNP, such that there is no residual reducing agent in the solution after removing the external electric field for plasma generation. The plasma discharge, gas-liquid separation, liquid collection and mercury ion detection can be achieved by this proposed microfluidic chip. The synthesized gold nanoparticles are further functionalized by 3-mercaptopropionic acid (3-MPA) for mercury ion detection. The 3-MPA-capped gold nanoparticles aggregate and result in a colour change of the solution due to the existence of Hg. The absorption spectra of the solution shifts from red to blue due to the cluster aggregation. The concentration of Hg can be quantitatively determined by UV-Vis spectrometry, and the limit of detection was found to be 10 M (0.2 ppm). This developed integrated microfluidic device provides a simple and on-demand method for synthesis of AuNPs and Hg detection in a single chip.
本研究展示了一种新型微流控芯片，该芯片能够利用大气压氦等离子体实现按需合成金纳米颗粒（AuNP）以及现场汞离子检测。该芯片并非采用传统化学反应方法，而是利用氦等离子体作为还原剂来还原金离子并合成AuNP，从而在去除用于产生等离子体的外部电场后，溶液中不会残留还原剂。所提出的这种微流控芯片能够实现等离子体放电、气液分离、液体收集以及汞离子检测。合成的金纳米颗粒通过3-巯基丙酸（3-MPA）进行进一步功能化处理以用于汞离子检测。由于汞的存在，3-MPA包覆的金纳米颗粒会聚集并导致溶液颜色发生变化。溶液的吸收光谱因团簇聚集而从红色变为蓝色。汞的浓度可通过紫外可见光谱法定量测定，检测限为10 M（0.2 ppm）。这种开发的集成微流控装置为在单个芯片中合成AuNP和检测汞提供了一种简单且按需的方法。
