An electrochemical method for the simultaneous determinations of Hg" concentration and total As"' and AsV concentration has been developed. The method does not require the additional preliminary step of the chemical reduction of AsV to As"', or oxidation of As"' to AsV before stripping analysis takes place. Also, the method for the simultaneous determination of Hg" concentration and As"' concentration is described. Measurements were performed in 0.1 M HCI using a gold-plated graphite electrode as sensor. Detection limits for both methods are below 0.4ppb. Relative standard deviation did not exceed 15 70. The possible interference by other trace metals was investigated. Analyses of natural water and industrial solutions were made using proposed methods and AAS. The t-test demonstrates that there was no significant difference between the results obtained with these methods. Proposed methods decrease the time of analysis because concentrations of the Hg" and arsenic ions were measured simultaneously. Also, the removal of the additional step of chemical reduction of AsV to AsIn or oxidation of As"' to AsV decreases analysis time, and also reduces the chance of contamination due to the use of additional reagents.
A method for detecting low concentrations of mercury ions with the help of direct current anodic stripping voltammetry (DCASV) is proposed. For this method, gold and gold-plated electrodes are used. To eliminate the influence of interfering organic surfactants, electrochemical method is used for the probe preparation. Less interference by inorganic substances is attained by the introduction of an additional state in the electrolysis at constant potential after pre-electrolysis, by which interfering elements are stripped from the deposit while mercury remains on the electrode. The lowest detection limit obtained was 0.16 pg/L using a gold electrode and a graphite electrode impregnated with a mixture of an epoxy resin and polyethylenamine with a gold cover. The latter electrode can be used for fifty analyses without changing the gold covering. The proposed method was used for the analysis of food, sewage, and drinking water.
Key indicatorsSingle-crystal X-ray study T = 297 K Mean '(C±C) = 0.003 A Ê R factor = 0.069 wR factor = 0.183 Data-to-parameter ratio = 13.3For details of how these key indicators were automatically derived from the article, see
This article proposes a method for detecting the concentration of gold ions in solutions with high oxidation/reduction potential (OW), such as aqua regia, a hypochlorite-iodine mixture, and a new proprietary liquid bromine carrier solution, by direct current anodic stripping voltammetry (DCASV). The working electrode is a graphite electrode impregnated with a mixture of epoxy resin and polyethylene amine. The article discusses: possible cause of a double stripping peak for gold appearing in voltammograms in aqua regia solution with electrolysis potentials less than -0.4 V; differences in coefficients of the working electrode's sensitivity in the above mentioned solutions. A relative standard deviation of the results in determining gold concentration in solutions of rock (ORP 0.9 V), which were obtained by the proposed method and by atomic-absorption spectrophotometry, did not exceed 0.2.Keywords: Gold, Rock, Stripping voltammetry, Noble metals At the present time, the most environmentally clean methods for dissolving gold, extracted from gold-containing materials, are non-cyanide methods, including methods of dissolving in aqua regia [ 11, hypochlorite-iodine mixture [2], or bromine solution [3]. All these solutions have high ORP (EoxIred > 0.9 V) All the described methods for gold analysis [4,5,6, 71 can be used in a solution with special pH and special composition. One of the most important problems in applying these methods for analysis of a solution with high ORP, is the destruction of a sensor in this solution. None of these methods can be used for analyzing solutions of rock, ores, or other gold-containing materials with high ORP without an additional solution treatment stage. Most authors suggest using different types of extraction for Au'" ions from these solutions [E, 91. This complicates and extends the analysis.The purpose of our work is: to search for an electrochemical stable working electrode to determine gold ions concentration in high ORP solutions (aqua regia, hypochlorite iodine mixture, or a new proprietary liquid bromine carrier solution); to develop a fast and simple selectivity and sensitivity method to analyze these solutions with high ORP without an additional solution treatment stage; to determine the cause for a double peak of gold appearing when changing the electrolysis potential in aqua regia; and to explain the difference in the coefficients of the working electrode's sensitivity in these solutions.To determine the degree of the working electrode's stability, its own potentials were measured as follows. An electrode was washed with distilled water and was placed in 0.1 M HCI. After 2-min. mixing of the solution, the electrode potential was measured relative to the reference electrode. The average result from three measurement was taken.To dissolve rock samples, the following method was used: rock samples were washed with concentrated HCI, H 2 0 , H2S04,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.