Ultratrace Determination of Silver, Gold, and Iron Oxide Nanoparticles by Micelle Mediated Preconcentration/Selective Back-Extraction Coupled with Flow Injection Chemiluminescence Detection

Abstract

A new method has been developed for the ultrasensitive determination of silver, gold, and iron oxide nanoparticles in environmental samples. Cloud point extraction was optimized and used as a means to extract and preconcentrate all nanoparticle species simultaneously from the same sample. The extracted nanoparticles were sequentially isolated from the surfactant-rich phase by a new selective back-extraction procedure and dissociated into their precursor metal ions. Each ion solution was injected in a flow injection analysis (FIA) manifold, accommodating the chemiluminogenic oxidation of luminol, in order to amplify chemiluminescence (CL) emission in a manner proportional to its concentration. Under the optimum experimental conditions, the detection limits were brought down to the picomolar and femtomolar concentration levels with satisfactory analytical features in terms of precision (2.0-13.0%), selectivity against dissolved ions, and recoveries (74-114%). The method was successfully applied to the determination of iron oxide, silver, and gold nanoparticles in environmental samples of different complexity, ranging from unpolluted river water to raw sewage. The developed method could also serve as a basis for future deployment of molecular spectrometry detectors for the selective determination and speciation analysis of nanoparticles in environmental applications.

Formation of Nanosilver from Silver Sulfide Nanoparticles in Natural Waters by Photoinduced Fe(II, III) Redox Cycling

“…As the separation of low concentrations of nAg from Ag 2 SNPs is challenging, the mixture of Fe(III) and Ag 2 SNPs exposed to simulated light and in the dark for different time periods was ultracentrifuged (3 kDa, 15 min, 9384g), respectively, and the pellet was washed with ultrapure water, followed by ultracentrifugation (3 kDa, 15 min, 9384g) again to remove all remaining silver ions. Afterward, the purified pellet was incubated in 10 mM H 2 O 2 for 20 min to dissolve silver particles, 22,23 On the other hand, the ratio of Ag 107 to Ag 109 was investigated by using a mixture of commercial AgNPs (1 mg/ L) and the synthesized Ag 2 107 SNPs (5 mg/L) in the presence of Fe(III) (2 mg/L) under light conditions. The mixture was exposed to the simulated sunlight and 10 mL samples were collected at 0, 4, 10, 24, 48, 72, and 96 h, respectively.…”

Speciation analysis of silver sulfide nanoparticles in environmental waters by magnetic solid-phase extraction coupled with ICP-MS

“…To enhance the extraction efficiency, parameters that commonly affect extraction were investigated according to previous studies, 21,25,36 3.2.1. Sample pH.…”

Understanding the fate and biological effects of Ag- and TiO2-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

“…In addition to common techniques like ultrafiltration, cross-flow-filtration and ultracentrifugation, new selective techniques like magnetic solid phase extraction (MSPE) (Su et al, 2014) are evolving. Cloud point extraction (CPE) (Tani et al, 1997;Tsogas et al, 2014) transfers a non-ionic surfactant from one liquid phase to another by heating. CPE and size specific CPE were ruled out by Fabricius et al (2014), but will have to be revisited even though the recovery rates are lower.…”