Fabrication and evaluation of MEMS thin-film AU working electrode for light metal detection

Abstract

In response to population growth, water resources are expected to aggravate. It is mainly due to human activities which slowly deteriorate the world’s environment. Through this action, the water quality around the world is degrading in quality. This would result in endangering human and ecosystem health furthermore raising the cost of water treatment. The threats that harm human health not only heavy metal but light metal as well. The consequence of light metal is not as serious as heavy metal, but it is also a concern for human health. Therefore, continuous monitoring of water quality is needed to identify water hardness and reducing this current issue. Conventional water quality measurement is a long process and require a long time to accomplish. The process starts from collecting water sample from various sources and transporting these samples to a laboratory for analysis. The result may be inaccurate due to different factors such as transportation duration and testing sequences.

In recent years, compact chemical sensor can be considered as a potential replacement of conventional centralized testing equipment due to the development of portable, sensitive and miniaturized chemical sensor which shows great perspective in this area. Aside from chemical sensor, anodic stripping voltammetry technique can be used for on-site evaluation. The reason for this technique to be employ is due to its simple operation, high sensitivity and portability.

Studies shows that chemically modified calixarene can be used to selectively bind variation of cationic and anionic. Therefore, some of the MEMS-based chemical sensors are further modified by drop-casting the working electrode with calixarene. Same concentration of calcium solution would be used to compare the sensitivity of non-modified sensor and modified sensor. The results of non-modified sensor and modified sensor for each experiment are presented and compared.

After the collection of different results, the modified MEMS-based chemical sensor by drop-casting the working electrode with 3µL of p-tert-butylcalix(6)arene showed higher peak current as compared to non-modified sensor. This indicates a potential to modify the sensors to increase its sensitivity to be used for electrochemical applications in on-site light metal detection field.