Current trends and challenges in sample preparation for metallic nanoparticles analysis in daily products and environmental samples: A review

Due to the increasing use of nanoparticles (NPs) in consumer products, it becomes necessary to develop different strategies for their detection, identification, characterization and quantification in a wide variety of samples. Since the analysis of NPs in consumer products and environmental samples is particularly troublesome, a detailed description of challenges and limitations is given here. This review mainly focuses on sample preparation procedures applied for the mostly used techniques for metallic and metal oxide NPs characterization in consumer products and most outstanding publications of biological and environmental samples (from 2006 to 2015). We summarize the procedures applied for total metal content, extraction/separation and/or preconcentration of NPs from the matrix, separation of metallic NPs from their ions or from larger particles and NPs' size fractionation. Sample preparation procedures specifically for microscopy are also described. Selected applications in cosmetics, food, other consumer products, biological tissues and environmental samples are presented. Advantages and inconveniences of those procedures are considered. Moreover, selected simplified schemes for NPs sample preparation, as well as usual techniques applied are included. Finally, promising directions for further investigations are discussed. [Display omitted] •Analysis and characterization of nanoparticles are of great concern now.•This review focuses on sample preparation prior to characterization of nanoparticles.•We include cosmetics, foods, daily products, biological and environmental samples.•Sample preparation is described for solid, liquid and gaseous samples.•Fractionation, speciation and preconcentration strategies are considered.