Electrochemical sensing of Hg(II) ions based on ultramicrotome-crafted strip ultramicroelectrode

The presence of heavy metal ions in the biosphere constitutes a significant source of pollution, posing severe threats to both human health and the environment. Thus, the accurate detection of heavy metal ions assumes paramount importance. The present study involves the preparation of electrochemical sensors based on strip ultramicroelectrode, enabling the detection of Hg2+. The electrochemical performance of strip ultramicroelectrode is characterized firstly. The Au strip ultramicroelectrode demonstrates exceptional suitability for the detection of Hg2+. Moreover, the acetate buffer is confirmed as an advantageous detection medium for Hg2+ owing to its slight influence on the result. The electrochemical detection parameters of the strip ultramicroelectrode, such as the pH value of the acetate buffer, enrichment potential, and enrichment time, have been optimized. The prepared electrochemical sensors based on strip ultramicroelectrode are utilized to detect the Hg2+ in tap water, snow melt water and bottled water. The detection limitation exceeds the thresholds established by the drinking water quality standards of China, the World Health Organization, and the European Union. The sensor prepared based on the strip ultramicroelectrode has exceptional accuracy, reliability, and practical applicability.

Recent Trends and Advances in Porous Metal-Organic Framework Nanostructures for the Electrochemical and Optical Sensing of Heavy Metals in Water

With the expansion and advancement in agricultural and chemical industries, various toxic heavy metals such as lead, cadmium, mercury, zinc, copper, arsenic etc. are continuously released into the environment. Intake of sources contaminated with such toxic metals leads to various health issues. Keeping the serious effects of these toxic metal ions in view, various organic-inorganic nanomaterials based sensors have been exploited for their detection via optical, electrochemical and colorimetric approaches. Since a chemical sensor works on the principle of interaction between the sensing layer and the analytes, a sensor material with large surface area is required to enable the largest possible interaction with the target molecules and hence the sensitivity of the chemical sensor. However, commonly employed materials such as metal oxides and conducting polymers tend to feature relatively low surface areas, and hence resulting in low sensitivity of the sensor. Metal-Organic Frameworks (MOFs) nanostructures are another category of organic-inorganic materials endowed with large surface area, ultra-high and tunable porosity, post-synthesis modification features, readily available active sites, catalytic activity, and chemical/thermal stability. These properties provide high sensitivity to the MOF based sensors due to the adsorption of large number of target analytes. The current review article focuses on MOFs based optical and electrochemical sensors for the detection of heavy metals.