Analysis of silver nanoparticles by flame atomic absorption spectrometry

Abstract

AbstractIntending to rate the quality of manufactured silver nanoparticles (AgNPs) products in the context that most of the publications in this field have focused on the residual AgNPs at trace levels, the primary goal of this report is to develop a fast and facile method for the speciation analysis of synthesized AgNPs – Ag(0) and Ag(I), using liquid‐liquid extraction (LLE) combined with flame atomic absorption spectroscopy (FAAS). Ag(I) in a pH 5 buffer solution was selectively extracted into an organic phase by dithizone, re‐extracted into an aqueous phase by HNO3, and then quantified by FAAS. In contrast, AgNPs in the initial aqueous phase were digested with HNO3 and H2O2 and determined by FAAS. The synthesized AgNPs samples were analyzed, with a silver content of 25 – 5000 mgL−1 and 50 ‐ 96% of AgNPs. The mass balance for silver confirmed that the speciation analysis of AgNPs agreed with the total analysis for silver in these samples. The average recovery of the spiked samples reached 98.9 ± 1.5% (P = 0.95). The method's precision was determined via the repeatability and reproducibility of 0.027 and 0.036 mgL−1 (P = 0.95). Both AgNPs and ionic silver were diluted to the same extent and quantified in atomized silver form, leading to a similar limit of detection (LOD) and quantification (LOQ) of 0.058 mgL−1 and 0.19 mgL−1 (P = 0.95), respectively. The proposed procedure was reliable and low‐cost that barely requires too advanced instruments to analyze AgNPs products at high concentration levels.