A Review of Analytical Techniques for the Determination and Separation of Silver Ions and Its Nanoparticles

Abstract

Many articles have already been published dealing with silver ions and its nanoparticles, but mostly from the environmental and toxicological point of view. This article is a review focused on the various analytical techniques and detection platforms used in the separation and determination of mentioned above species, especially on the trace concentration level. Commonly used are optical methods because of their high sensitivity and easy automation. The separation methods are mainly used for the separation and preconcentration of silver particles. Their combination with other analytical techniques, mainly inductively coupled plasma mass spectrometry (ICP-MS) leads to very low detection limits of analysis. The electrochemical methods are also powerful and perspective mainly because of the fabrication of new sensors designed for silver determination. All methods may be combined with each other to achieve a synergistic improvement of analytical parameters with an impact on sensitivity, selectivity and reliability. The paper comprises a review of all three types of analytical methods on the determination of trace quantities of silver ions and its nanoparticles.

Keywords: AgNPs; analytical methods; silver; silver detection; silver nanoparticles; trace amounts.

Figure 1

The graphical depiction of the sensor for Ag⁺ ions selectivity and sensitivity compared to other metal ions based on data given in paper [38]. UV-Vis absorption ratio (A520/A660) of gold nanoparticles dispersions mixed with thiamazole in the presence of Ag⁺ with a concentration of 5 nM. The concentration of Pb²⁺, Hg²⁺ and Cu²⁺ was 50 nM. The concentration of other ions was 100 nM (concentration of thiamazole was 2 μM; pH: 7.5).

Figure 2

The depiction of the structures of some compounds commonly used as silver ionophores based on data given in paper [1].

Figure 3

The graphical depiction of two sophisticated procedures for stripping voltammetry trace determination of Ag⁺ ions based on data given in paper [1]. (A) Accumulation with ligand silver bond; (B) stripping voltammetry using microprobe.

Figure 4

The depiction of a chronoamperogram of a dispersion containing 20 ng L⁻¹ silver nanoparticles with a characteristic diameter of 20 nm in 0.02 mol.dm⁻³ NaClO₄ measured at 0.70 V vs. SCE using carbon fiber microelectrode based on the data given in [24]. Inset: AgNPs size distribution calculated from the spikes measured in the time domain from 2 to 10 s.