Influence of Particle Coating and Matrix Constituents on the Cloud Point Extraction Efficiency of Silver Nanoparticles (Ag-NPs) and Application for Monitoring the Formation of Ag-NPs from Ag⁺

Abstract

For the quantification of silver nanoparticles (Ag-NPs) in environmental samples using cloud point extraction (CPE) for selective enrichment, surface modification of the Ag-NPs and matrix effects can play a key role. In this work we validate CPE with respect to the influence of different coatings and naturally occurring matrix components. The Ag-NPs tested were functionalized with inorganic and organic compounds as well as with biomolecules. Commercially available NPs and NPs synthesized according to methods published in the literature were used. We found that CPE can extract almost all Ag-NPs tested with very good efficiencies (82-105%). Only Ag-NPs functionalized with BSA (bovine serum albumin), which is a protein with the function to keep colloids in solution, cannot be extracted. No or little effect of environmentally relevant salts, organic matter, and inorganic colloids on the CPE of AgNPs was found. Additionally we used CPE to observe the in situ formation of Ag-NPs produced by the reduction of Ag(+) with natural organic matter (NOM).

Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles

“…The reported values of limit of detection (LOD) for CPE are generally in the sub μg kg −1 range, although a LOD as low as 0.6 ng kg −1 has been reported for waste water sample by using electrothermal atomic absorption spectrometry [14][15][16]. However, studies have shown that the extraction efficiency was significantly reduced when Ag NPs were coated with proteins, which limits its application in biological samples [17].…”

Screening Small Metabolites from Cells as Multifunctional Coatings Simultaneously Improves Nanomaterial Biocompatibility and Functionality

“…The XPS data showed that the ratios of lattice oxygen/adsorbed oxygen in nAg‐sorbitol, nAg‐cysteine, and naked nAg were 0.71, 2.55, and 0.35, respectively (Figure S10, Supporting Information). The functional groups coated onto nAg sequestered oxygen from the air 57. Therefore, less adsorbed oxygen could be detected on the surface of nAg wrapped by d ‐sorbitol or l ‐cysteine.…”

Separation and Determination of Silver Nanoparticles

“…The interference of Ag + was negligible when the concentration of Ag + was lower than two times that of AgNPs [5]. It was successfully applied to determine AgNPs and Ag + in environmental samples such as commercial available products [7], HepG2 cells [9] and municipal wastewater [10,11]. Previous study reported the speciation analysis of AgNPs and Ag + in six antibacterial products based on CPE [7].…”