title: Species selective preconcentration and quantification of gold nanoparticles using cloud point extraction and electrothermal atomic absorption spectrometry.
abstract: The determination of metallic nanoparticles in environmental samples requires sample pretreatment that ideally combines pre-concentration and species selectivity. With cloud point extraction (CPE) using the surfactant Triton X-114 we present a simple and cost effective separation technique that meets both criteria. Effective separation of ionic gold species and Au nanoparticles (Au-NPs) is achieved by using sodium thiosulphate as a complexing agent. The extraction efficiency for Au-NP ranged from 1.01 ± 0.06 (particle size 2 nm) to 0.52 ± 0.16 (particle size 150 nm). An enrichment factor of 80 and a low limit of detection of 5 ng L(-1) is achieved using electrothermal atomic absorption spectrometry (ET-AAS) for quantification. TEM measurements showed that the particle size is not affected by the CPE process. Natural organic matter (NOM) is tolerated up to a concentration of 10 mg L(-1). The precision of the method expressed as the standard deviation of 12 replicates at an Au-NP concentration of 100 ng L(-1) is 9.5%. A relation between particle concentration and the extraction efficiency was not observed. Spiking experiments showed a recovery higher than 91% for environmental water samples.
authors: Department of Chemistry, Technische Universität München, 85748 Garching, Germany. georg.hartmann@tum.de
authors: Georg
authors: G
authors: Hartmann
authors: Michael
authors: M
authors: Schuster
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D006046:Gold / Q000302:isolation & purification*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D013054:Spectrophotometry, Atomic / Q000379:methods; D013501:Surface-Active Agents / Q000737:chemistry; D013885:Thiosulfates / Q000737:chemistry; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D006046:Gold; D017830:Octoxynol; D011092:Polyethylene Glycols; D013501:Surface-Active Agents; D013885:Thiosulfates; D062065:Wastewater; D014874:Water Pollutants, Chemical; C010615:Nonidet P-40; C017717:sodium thiosulfate