Preparation of Ag/C Nanocomposites Based on Silver Maleate and Their Use for the Analysis of Iodine Ions

Abstract

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In the present study, a detailed analysis of the preparation of Ag/C nanocomposites through the thermolysis of silver maleate was carried out. Thermolysis products are nanocomposites containing silver nanoparticles (NPs) uniformly distributed in a stabilizing carbon matrix. The composition, structure, and properties of the obtained nanocomposites were studied using IR-spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). This article reports on the possibility of using Ag/C nanocomposites to create new indicator papers that are sensitive to iodide ions in the concentration range of 0.03–1.6 mg/L (0.24–12.6 μM). The developed papers are used in a technique based on the oxidation of iodides with the formation of molecular iodine, which is extracted in an air stream and transferred to a sensitive paper layer containing silver NPs. The interaction of silver NPs with iodine leads to optical changes that can be tracked using a conventional scanner.

Preparation of Reactive Indicator Papers Based on Silver-Containing Nanocomposites for the Analysis of Chloride Ions

“…As is known, the spectral characteristics of RIP samples and the intensity of their coloration are affected by the content of nanoparticles [ 22 , 24 , 42 , 44 , 45 , 46 , 47 , 48 , 49 ]. This point is important from the point of view of chemical analysis, since it is well known that the color intensity of any test strip, as well as the content of the reagent in it, has a strong influence on the metrological characteristics of the determination, such as the limit of detection (LOD) and the limits of quantification (LOQs).…”

“…To completely oxidize chloride ions, any non-volatile oxidizing agent whose potential is greater than 1.36 V can be used, for example, potassium permanganate (1.51 V). However, it should be considered that, when using it, the determination of chlorides will be interfered with by bromides and iodides in the ratio of 1:1 [ 49 , 50 ], which leads to significant limitations in the use of the technique. Namely, it cannot be used in the analysis of mineral, marine, and associated formation waters without additional sample preparation.…”