Asymmetric Flow-Field Flow Fractionation Hyphenated ICP-MS as an Alternative to Cloud Point Extraction for Quantification of Silver Nanoparticles and Silver Speciation: Application for Nanoparticles with a Protein Corona

Abstract

Production and application of nanoparticles in consumer products is at an all-time high due to the emerging field of nanotechnology. Direct detection and quantification of trace levels of nanoparticles within consumer products is very challenging and problematic. Although multiple methodologies are available for this purpose, each method has its own set of limitations. Herein, we developed an analytical platform consisting of asymmetric flow-field flow fractionation (AF4) coupled with inductively coupled plasma mass spectroscopy (ICP-MS) for the speciation and quantification of silver ions and silver nanoparticles at the ng/kg level (ppt). AF4 is utilized to concentrate the nanoparticles, and ICP-MS acts as the detector. The protein corona that forms upon exposure of nanoparticles to bovine serum albumin was utilized as a nanoparticle stabilization and AF4 recovery enhancement mechanism. Speciation of silver ions and nanoparticles was achieved with the assistance of penicillamine as a complexation ligand. The effect of nanoparticle size, surface coating, and ionization state toward the detection and quantification of the developed methodology was evaluated. The detection limit was found to be 4 ng/kg with the application of a 5 mL sample loop. Further application of this developed methodology on environmentally relevant samples was demonstrated by the analysis of Arkansas River water spiked with silver nanoparticles and nanoparticle spiked into humic acid solution (50 mg/L) at an environmentally relevant level.

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

“…Asymmetric flow field flow fractionation (AF4) is another popular technique in characterizing metallic and metal oxide NPs [11,12]. We previously reported a robust method using AF4 coupled with ICPMS for the online enrichment, speciation, and quantification of Ag + and NPs [13]. A detection limit as low as 0.004 μg kg −1 was achieved and the method also demonstrated its ability in analyzing bovine serum albumin (BSA) coated Ag NPs.…”

Investigation of cloud point extraction for the analysis of metallic nanoparticles in a soil matrix

“…Previous studies, employing TEM to determine the size of the AuNPs 13 and AgNPs 16 , showed that the size was unaffected by CPE, even in the presence of acid. The redisolution of the surfactant-rich phase sample in alcohol after CPE may explain the observed difference with the current study (disaggregation).…”

“…10, 11 Single channel techniques such as field flow fractionation can also be utilized to pre-concentrate MNP samples; in this case, a large volume of sample is injected in the channel and the focusing step is extended. 12, 13 This method can be coupled online to appropriate detectors or concentrated fractions can be collected for off-line analysis. However, interactions can and do occur with the accumulation wall membrane due to the increased focusing time.…”

An improved methodology of asymmetric flow field flow fractionation hyphenated with inductively coupled mass spectrometry for the determination of size distribution of gold nanoparticles in dietary supplements

“…AF4 can be hyphenated with other techniques including ICP-MS, multi-angle light scattering and, UV-visible absorbance. Multiple applications of these hyphenated techniques have been demonstrated in recent literature reports [10,12,[19][20][21].…”