Detection and Characterization of Silver Nanostructures in Consumer Products

Silver (Ag) is one among the few nanomaterials which are widely used across several consumer products. However, there is limited research on detection and characterization of Ag nanostructures in complex matrices such as consumer products. Most previous studies for analytical method development were based on Ag liquid formulations or with standard materials. In this study, a total of fifteen commercial products including dietary supplements, deodorants, fabric, skin protectants, and toothpastes that declare nano or colloidal Ag ingredients were investigated. To characterize the quantity, size, size distribution, and morphology of Ag nanoparticles used in the products, several analytical instrumental techniques such as inductively coupled plasma-mass spectroscopy (ICPMS), dynamic light scattering (DLS), differential centrifugal sedimentation (DCS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectrometry (EDS) were employed. Study results showed that Ag nanoparticles were found in eleven of the fifteen investigated commercial products, where the majority of Ag nanoparticles were spherical and smaller than 50 nm. The advantages and limitations of size characterization techniques were discussed with respect to product type. A combination of characterization techniques was highly desired based on the product type and other ingredients used to confirm the presence of nanostructures in consumer products.