Engineered Nanomaterials: Classification and Strategies for Physicochemical Characterization and Advanced Analytical Techniques for the Measurement of Nanomaterials in Plant Samples

Abstract Manufacture of, and demand for, engineered nanomaterials (ENMs, having at least one of three dimensions in the 1–100 nm size range) used in different goods and products have increased significantly in recent years. ENMs have become prominent in the industrial and scientific fields. Global market value for ENMs is increasing day by day. Different ENMs used in agriculture have the potential for precise delivery of agrochemicals for improving disease resistance, plant growth, and nutrient use. Agricultural productivity can be improved through nanomaterial-induced genetically improved animals and plants, site-specific drug and gene delivery of molecules at cellular/molecular levels in animals and plants, and nanoarray-based genetic modification in animals and plants under stress conditions. Nanoencapsulated products show the ability of more effective and site-specific use of pesticides, insecticides, and herbicides in an ecofriendly greener way. The majority of the reported studies point to the positive impacts of nanoparticles on plant growth with a few isolated studies pertaining to negative effects. With increasing production and wider applications, ENMs are expected to become routinely present in natural ecosystems and may be directly released into air, water, sediment, and soil media during their manufacturing, use, and disposal. ENMs in the environment pose unique detection and quantification problems because of their small size and low concentration and because of the high background level of incidental and naturally occurring nanoparticulate matter, often with similar elemental composition. It also requires understanding of how an ENM may be altered in specific environmental conditions. Characterization of ENMs provides data on properties such as bulk chemical composition, particle size and shape, and mineralogy. Particle size and distribution are often valuable measurements because of their importance in fate, transport, and possible ecotoxicity. Because several parameters need to be determined for full characterization of ENMs, multiple analytical techniques should be used to accurately assess engineered nanoparticles in environmental samples. In this chapter, we discuss different aspects of ENMs including detection, characterization, and measurement techniques for nanomaterials in plant samples. These include chromatography, flow field fractionation, electron microscopy, light scattering, and autofluorescence techniques, among others.