Rapid Chromatographic Separation of Dissoluble Ag(I) and Silver-Containing Nanoparticles of 1–100 Nanometer in Antibacterial Products and Environmental Waters

Abstract

Sensitive and rapid methods for speciation analysis of nanoparticulate Ag (NAg) and Ag(I) in complex matrices are urgently needed for understanding the environmental effects and biological toxicity of silver nanoparticles (AgNPs). Herein we report the development of a universal liquid chromatography (LC) method for rapid and high resolution separation of dissoluble Ag(I) from nanoparticles covering the entire range of 1−100 nm in 5 min. By using a 500 Å poresize amino column, and an aqueous mobile phase containing 0.1% (v/v) FL-70 (a surfactant) and 2 mM Na 2 S 2 O 3 at a flow rate of 0.7 mL/min, all the nanoparticles of various species such as Ag and Ag 2 S were eluted in one fraction, while dissoluble Ag(I) was eluted as a baseline separated peak. The dissoluble Ag(I) was quantified by the online coupled ICP-MS with a detection limit of 0.019 μg/L. The NAg was quantified by subtracting the dissoluble Ag(I) from the total Ag content, which was determined by ICP-MS after digestion of the sample without LC separation. While the addition of FL-70 and Na 2 S 2 O 3 into the mobile phase is essential to elute NAg and Ag(I) from the column, the use of 500 Å poresize column is the key to baseline separation of Ag(I) from ∼1 nm AgNPs. The feasibility of the proposed method was demonstrated in speciation analysis of dissoluble Ag(I) and NAg in antibacterial products and environmental waters, with very good chromatographic repeatability (relative standard deviations) in both peak area (<2%) and retention time (<0.6%), excellent spiked recoveries in the range of 84.7−102.7% for Ag(I) and 81.3−106.3% for NAg. Our work offers a novel approach to rapid and baseline separation of dissoluble metal ions from their nanoparticulate counterparts covering the whole range of 1−100 nm.

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 quantification process using CE-ICPMS was first evaluated on multiple types of Ag NPs. Several previous studies have reported size-dependent signal response of nanoparticles in ICPMS, which can be explained by the variation in the nebulization efficiency [9,26]. We first spiked BGE with 30 μg kg −1 of CA coated Ag nanoparticles in different sizes to investigate their signal response.…”

“…Several liquid chromatographic methods have been developed for the speciation of nanoscale silver [9,10]. By using ICPMS as the detection method, LODs can easily reach a sub μg kg −1 level.…”

“…By using ICPMS as the detection method, LODs can easily reach a sub μg kg −1 level. However, online speciation and quantification of Ag NPs and ionic Ag remain a challenge because of the relatively low recovery due to irreversible binding of analyte to the stationary phase [9,10]. Asymmetric flow field flow fractionation (AF4) is another popular technique in characterizing metallic and metal oxide NPs [11,12].…”

Determination of emerging contaminants in environmental matrices

“…Nanoparticles technology is applied to a wide range of products in the fields of cosmetics, biomedicine, food and food packaging, bioremediation, coatings, electronics, catalysis and material sciences, among many others (Nel et al, 2006) (Christensen et al, 2010) (Nowack et al, 2011(Nowack et al, ) (2016. Particularly, silver nanoparticles (AgNPs) are used in consumer products due to a proved antimicrobial properties attributable to the release of Ag + (Zhou et al, 2014) (Xiu et al, 2012). Because of the massive and uprising tendency to use NPs in general and Ag-NPs in particular (Nowack et al, 2011), the release of nano-residues into different compartments in the environment should be taken into account (López-Serrano et al, 2014) (Schaumann et al, 2015), being water bodies particularly at risk, as they act as a sink for most environmental contaminants (Farré et al, 2011).…”

“…As a consequence, analytical scientists are dedicating efforts to develop selective, robust and reliable fit-for-purpose methods that are able to separate, isolate and measure NPs to characterise the number based-particle size distribution (PSD). To date, Asymmetric Flow Field Flow Fractionation (AF4) (Poda et al, 2011) (Loeschner et al, 2013) (Mitrano et al, 2012a), chromatographic techniques (Zhou et al, 2014) and filtration (Mitrano et al, 2015) are among the most frequently used techniques to separate NPs, often coupled to light scattering, UV or Inductively Couple Plasma Mass Spectrometry (ICP-MS) detectors (Barahona et al, 2016) (Cascio et al, 2014). Each measuring technique and approach exhibits its own advantages and limitations and a combined use of all of them following a multimethod approach has been sometimes proposed since the information from each individual method is usually complementary ( Hagendorfer et al, 2012).…”