Separation of silver ions and silver nanoparticles using cloud point extraction for the determination by flame atomatic absorption spectrometry

Abstract

In this research, a method for separation and determination of silver nanoparticles (AgNPs) and total amount of silver was proposed by using Triton X-114 based cloud point extraction (CPE) and flame atomic absorption spectrometry (FAAS). The separation of AgNPs from ionic silver species (Ag+) was achieved by addition of sodium thiosulfate solution (Na₂S₂O₃). The extracted AgNPs was concentrated into the surfactant phase and digested with H2O2 prior to the analysis by FAAS. The extraction of AgNPs from samples was performed by using 20 mM of (Na₂S₂O₃) at pH 3.The recovery of AgNPs was in a range of 86.74-87.95 %. The limit of detection (LOD) of AgNPs was 0.27 mg L-1. The total amount of silver was also determined by oxidizing AgNPs in solution to Ag+. L-cysteine was added to form a neutral complex with silver ions before CPE was performed. The recovery of total amount of silver was in a range of 93.31-95.76% when 20 mM L-cystein solution was used in the analysis of solutions containing 0.5-1.0 mg L-1 of total Ag at pH 1-5. The limit of detection (LOD) of the total amount of silver was 0.11 mg L-1.