Nanosensors and other techniques for detecting nanoparticles in the environment

Abstract

The recent advances in nanotechnology and the corresponding increase in the use of nanomaterials in products of every sector of society have resulted in uncertainties regarding their environmental impacts. Nanoparticles are becoming emerging contaminants for which human and ecological exposure and effects need to be assessed to characterize the hazards and risks [1, 2]. However, detecting nanomaterials in the environment is a demanding task, not only because of the extremely small size of the particles and their potential sequestration and agglomeration, but also because of their unique physical and chemical characteristics. This presentation will assess several ways to tackle the challenge of engineered nanomaterials detection in the environment. The need for standard reference and testing materials as well as methodology for suspension preparation and testing will be highlighted. Special attention will be paid to the approach that recently raised is the socalled “third way” in analytical nanoscience and nanotechnology (AN&N) that involves the application of nanomaterials based sorbents or sensors to nanomaterials extraction and/or determination [3]. The presented overview of the available analytical techniques used for the detection and characterization of nanoparticles in environmental matrices including particle-size analysis, particle-fraction concentration counts, surface-area analysis, morphology, and particle chemical composition analysis will pointed out how nanoparticles analysis is still in its infancy. Sample preparation, imaging techniques (electron microscopy, scanning electron microscopy, or X-ray microscopy), separation methods (e.g. flow field fractionation, electrophoresis, liquid chromatography, hydrodynamic chromatography), and detection/characterization techniques (e.g. light scattering, inductive coupled plasma, mass spectrometry) will be discussed. There are already a few non-well resolved protocols established for the determination of some of them. For example, in the case of wet metals digestion followed by ICP-MS and complemented by SEM or TEM to demonstrate that these metals were present as nanoforms. Clearly the analysis of nanoparticles in the environment is not question of a single analytical technique, but rather a combination of multiple sophisticated procedures and instrumentation. Further development and application of these promising methods will provide research opportunities and challenges for the foreseeable future.