Ion association reactions: theoretical and experimental perspectives for quantification of pollutants

Various complex formation reactions are often encountered while detecting and quantifying pollutants in environmental matrices by using novel analytical techniques. The behavior of complexes changes with solvent, temperature, pH, etc. In the current article, a systematic investigation has been done on the formation of ion associates to analyze different categories of environmental pollutants. Therefore, ion association (IA), like electrostatic interaction, for the detection and quantification of metals, metalloids, surfactants, and pharmaceutical compounds (PCs), has been considered in solutions. Future perspectives on microplastics (MPs), nuclear waste, and other micropollutants have also been presented. Simple spectrophotometric characteristics of such complexes are described in detail, considering Bjerrum's idea of IA formation in dilute solutions. One section deals with the optimization of parameters for the quantification of analytes. The applicability of complex forming strategies in real-field scenarios and comparative accounts of different analytical techniques has been discussed. General chemistry, including thermodynamics and theoretical aspects of the formation of the complexes, is also reported. Lastly, existing challenges and future perspectives in this field are briefly described.