title: The importance of evaluating the real metal concentration in nanoparticles post-synthesis for their applications: A case-study using silver nanoparticles.
abstract: To determine whether the effect observed in a study is related to the nanoparticle only or to their synergic effect with the "free" metal ions, the real concentration of silver (104±8 and 100±2 mg L(-1)) after AgNP synthesis is obtained through ICP-MS and ICP OES in the solution after the AgNP synthesis and in different fractions after centrifugation (at 8100 g for 40 min). From the resuspension of the AgNP contained in the solution (AgNP-total) after synthesis (AgNP-res), concentrations of 49±3 and 51±3 mg L(-1) are found and concentrations of 50±7 and 47±2 mg L(-1) in the supernatant (Ag-sup) are found using ICP-MS and ICP OES respectively. The characterization of AgNP-total, AgNP-res and Ag-sup is performed by HRTEM and UV-vis, corroborating the results in terms of Ag determination, and indicates that half of the total silver concentration is in the AgNP form and that the other half is in the "free" silver form. The results of the stability test of the NPs indicate a 7% decrease in Ag as NP three months after its synthesis.
authors.affiliation: Spectrometry, Sample Preparation and Mechanization Group, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology for Bioanalytics, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil.
authors.forename: Rodrigo Moretto
authors.initials: RM
authors.lastname: Galazzi
authors.affiliation: Institute of Science and Technology, Federal University of São Paulo, 12231-280 São José dos Campos-SP, Brazil.
authors.forename: Elias de Barros
authors.initials: Ede B
authors.lastname: Santos
authors.affiliation: Spectrometry, Sample Preparation and Mechanization Group, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology for Bioanalytics, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Caurin
authors.affiliation: Spectrometry, Sample Preparation and Mechanization Group, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology for Bioanalytics, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil.
authors.forename: Gustavo de Souza
authors.initials: Gde S
authors.lastname: Pessôa
authors.affiliation: Functional Materials Laboratory, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil.
authors.forename: Italo Odone
authors.initials: IO
authors.lastname: Mazali
authors.affiliation: Spectrometry, Sample Preparation and Mechanization Group, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology for Bioanalytics, Institute of Chemistry, University of Campinas - Unicamp, P.O. Box 6154, Campinas, SP 13083-970, Brazil. Electronic address: zezzi@iqm.unicamp.br.
authors.forename: Marco Auréli Zezzio
authors.initials: MA
authors.lastname: Arruda
mesh_terms: D016477:Artifacts; D002498:Centrifugation; D053768:Metal Nanoparticles / Q000737:chemistry*; D008872:Microwaves; D036103:Nanotechnology; D012834:Silver / Q000032:analysis* / Q000737:chemistry*
chemical_list: D012834:Silver
keywords: Applications; Characterization; Silver determination; Silver nanoparticles