SILVER NANOPARTICLES: SYNTHESIS, SOLUBILITY, AND LEACHING OF COMMERCIAL PRODUCTS

abstract: In recent years, products advertised to contain nanosilver have become increasingly popular; however, while companies often advertise for nanosilver products, little regulation occurs to verify that these products actually contain silver nanoparticles. Furthermore, there currently exists much dispute regarding the safety and toxicity of silver nanoparticles. As more and more products incorporate nanosilver, the resolution of this dispute proves progressively important. The present study addressed these issues, with goals to synthesize silver nanoparticles, determine the solubility of the synthesized silver nanoparticles, and to evaluate leaching of nanosilver from commercially produced food storage containers. The silver nanoparticles were synthesized by a procedure devised by Leopold and Lendl, and subsequently evaluated for size and distribution by ICP-MS (Inductively Coupled Plasma Mass Spectrometry), SEC (Size Exclusion Chromatography), and DLS (Dynamic Light Scattering). The results indicated an average particle size of approximately 85 nm and a relatively monodispersed solution with a polydispersity value of 0.1245. The solubility of the nanoparticles was then examined using a dialysis experiment; however, the results of the dialysis experiments were inconclusive due to an aggregation that occurred which prevented the silver from diffusing out of the dialysis tubing. Lastly, commercially produced food storage containers advertised to contain silver nanoparticles were examined. These containers were digested using microwave assisted digestion, and subsequently analyzed using ICP-MS. It was determined that the containers contained between 7 .5 and 27 ug of silver per gram of container, and that the silver was not distributed uniformly throughout the container. While ICP-MS indicated the presence of silver, SEM (Scanning Electron Microscopy) failed to unambiguously identify silver nanoparticles in the container. The food storage containers were also examined for silver leaching under various conditions; it was found that the containers leached most greatly following exposure to an acidic solution and leached the least due to exposure to UV light. However, additional trials of the leaching experiments must be performed to validate the results obtained in these experiments