Optical detection of low concentrations of toxic nano particles in saline solutions; approximating a pseudo-estuary environment

One of the holy grails of environmental toxicology is the detection of very low concentrations oftoxic nanoparticles in the aquatic environment [1]. In the laboratory there are established methods that enablethese measurements to be made. SEM can be used with a sample where the liquid has been evaporated and thiscan reveal size, shape and chemical composition. Dynamic light scattering or laser diffraction are alsoestablished methods of particle characterisation;providing both size and shape information. SPR is label freedetection, but particles can be identified as the SPR angle is directlty determined by the particles refractiveindex. In this paper we explore the detection of Ag nanoparticles and silver nitrate in de-ionised water and salinesolution. The detection of the SPR phase response is also measured, to explore extended detection sensititivty.