Gold and silver nanoparticles and indicator dyes as active agents in colorimetric spot and strip tests for mercury(II) ions: a review

This review with 111 references covers recent progress made in the field of strip tests and spot tests for quantitative determination of mercury(II) ions. Following an introduction into the subject and the fundamentals of colorimetric determination, we first cover methods for synthesis and characterization of gold and silver nanoparticles (NPs) and give representative examples. The next sections cover (a) methods for dye-based detection of Hg(II) ions (categorized into azo, acridine, anthraquinone, di-/triarylmethane, nitro/nitroso, cyanine, triazole, oxazine, thiazine, dioxazine and xanthene dyes), and (b) techniques for immobilization of active agents (NPs and indicators) on the solid support. A conclusion section discusses current challenges and trends in future research.