Fluorescent sensors to monitor Ni(II) in complex environments

Abstract

Pollution from heavy metals will continue to depreciate the health of organisms and contaminate landscapes and water bodies; becoming progressively worse as time goes on. Nickel is one such heavy metal, and is known to cause a number of negative health effects by inducing asthma, conjunctivitis, pneumonitis, inflammation, skin allergies, lung fibrosis, infections in the respiratory tract, effects to the immune system, and cancer of the lungs, nose, sinuses, stomach and throat. Whilst nickel is a naturally occurring element in our environment, the major source of nickel dispersion is anthropogenic activities, which can be controlled and changed. To minimise and regulate nickel pollution, it is important to be able to monitor the concentration of nickel ions in a variety of media. The development of analytical tools to identify and quantify chemical species in complex fluids is of interest to many, from environmental scientists to forensic investigators to biological researchers. Fluorescent sensing offers the sensitivity required for such studies. The goal of this work is to develop a metal sensing system which is simple to use and can report on nickel concentrations, with an aim of working towards real-time on-site detection. This would contribute to monitoring heavy metal pollution in our environment. In order to determine suitable, selective, sensitive and applicable Ni(II) sensors, literature probes and derivatives were synthesised and analysed. Issues with selectivity of single probes were addressed by the study of combinatorial assays. Additional work on sensing systems led to the discovery of a simple method for optically detecting the ascorbate anion. Since nickel is a ubiquitous, highly valued metal that is encountered in everyday life, it is essential that monitoring its concentration in the environment is upheld. By utilising organic and analytical chemistry, sensing measurements can be improved which can lead to better practices.