Determination of gold in geological materials by atomic absorption spectrometry after bromine and hydrochloric acid extraction at room temperature

Reddi, G. S.; Ganesh, S.; Rao, C. R. M.; Ramanan, V. R. V.

doi:10.1016/0003-2670(92)80136-u

Cited by 15 publications

(7 citation statements)

References 4 publications

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“…According to the results of our previous investigations [4], the maximum distribution coefficient for platinum(IV) and the maximum selectivity coefficients for Fe(III) and Cu(II) are attained when platinum is extracted with TBP from solutions in a mixture of ; these conditions best correspond to the conditions of sample introduction into the atomizer in determining platinum [5]. Based on these data, we selected the conditions for the extraction-chromatographic separation of Pt(IV) with the simultaneous removal of Fe(III) and Cu(II).…”

Section: Resultsmentioning

confidence: 96%

mentioning

confidence: 99%

“…For this method, extraction chromatography using oxygen-containing extractants as the stationary phase offers most promise as the preconcentration method. Among the extractants is tributyl phosphate (TBP), which allows the reversible extraction of platinum(IV) as chloride complexes and, correspondingly, makes possible the preconcentration of platinum under conditions of a chromatographic experiment [4,5].The aim of this work was to select the conditions for the extraction-chromatographic preconcentration of Abstract -The conditions for determining platinum by electrothermal atomic absorption spectrometry after its extraction-chromatographic preconcentration and separation from iron(III) and copper(II) were selected. A procedure was developed that allows 0.01-0.1 mg/L platinum to be determined with a relative standard deviation of 5-7 % in the presence of 1000-fold amounts of Fe(III) and Cu(II).…”

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confidence: 99%

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Determination of platinum by atomic absorption spectrometry with chromatographic preconcentration from aqueous solutions

2005

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The determination of platinum-group metals in complex samples, including platinum-containing ores, products of their processing, catalysts, biologically active samples, and medicines, has always been a complex analytical task for any analytical method. The main difficulties are related to the low concentrations of platinum-group metals in test objects and to the effect of sample matrix on the analytical signal.Electrothermal atomic absorption spectrometry (ETAAS) is one of the most widely used methods for determining platinum-group metals. It is characterized by high selectivity and the lowest detection limits for platinum-group methods ( ≤ 10 for Pt) at the introduction of minor volumes of test solutions into the atomizer.However, in the majority of papers on the determination of platinum-group methods by atomic absorption spectrometry, e.g., in [1][2][3], it was noted that matrix components significantly affect the analytical signal, especially when the concentration of matrix components is several orders of magnitude higher than that of the analyte. This effect must be studied and taken into account in each particular case. Different methods for correcting for nonselective absorption can eliminate so-called spectral interferences but do not solve the problem of matrix effects due to chemical interactions of platinum-group metals with concomitant impurities in the test solution and solid and gas phases in the atomizer. In the last case, the general solution is to preliminarily separate the analytes from the concomitant impurities. The rapid direct analysis of samples of complex composition by EYAAS is possible only after the thorough optimization of the parameters of the atomic absorption spectrometer, including the knowledge of the behavior of sample vapors in the atomizer. Note that no systematic data were found on the effect of matrix components, such as Fe, Cu, Ni, Co, and others in determining platinum by ETAAS with a Massmann graphite furnace. The use of modifiers cannot fully eliminate the inhomogeneity of sample vapors in the atomizer. In addition, the separation of analytes from the matrix significantly simplifies the calibration of the atomic absorption spectrometer.Although methods for the separation of platinum and platinum-group metals have long been sought, the number of methodological solutions suitable for ETAAS is limited [2]. The majority of procedures for the extraction and adsorption preconcentration of platinum-group metals is based on the use of extractants and adsorbents bearing nitrogen-and sulfur-containing functional groups; these reagents cannot extract analytes from aqueous solutions of the composition acceptable for ETAAS [3]. Another important requirement for the method for platinum preconcentration and extraction, irrespective on the method for its subsequent determination, is the composition of the initial solution. Methods for transferring platinum to solutions are based mainly on the formation of chloride complexes. Therefore, extraction, adsorption, and chromatographic methods...

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Section: Resultsmentioning

confidence: 96%

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confidence: 99%

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confidence: 99%

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Determination of platinum by atomic absorption spectrometry with chromatographic preconcentration from aqueous solutions

2005

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“…[52][53][54][55][56][57][58] Mixtures of HCl, HBr and Br2 were also used for the extraction of gold from geological matrices prior to AAS detection. 59 The high resistance of ruthenium, rhodium, osmium and iridium to an attack by a mixture of acids, including aqua regia, limits the use of a direct wet digestion procedure to their quantitative transformation into soluble species. The metals can be transformed into solution by an aqua regia treatment when accompanying (at low % levels) platinum and paladium 60 or common metals 61 in alloys.…”

Section: Wet Acid Treatmentmentioning

confidence: 99%

Sample Digestion Methods for the Determination of Traces of Precious Metals by Spectrometric Techniques

Balcerzak

2002

ANAL. SCI.

168

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Recent advances in digestion methods used in the analysis of precious metal samples by spectrometric techniques are reviewed. The applicability of a fire assay, a wet acid treatment, chlorination and alkaline oxidizing fusion to a quantitative recovery of metals from various materials is discussed. Data on the precious metal contents obtained by using particular digestion methods as well as UV-VIS spectrophotometry, atomic absorption spectrometry, atomic emission spectrometry and inductively coupled plasma mass spectrometry in the examination of various samples are tabulated.

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“…The main works include applications of the following techniques: flame atomic absorption spectrometry (FAAS) [4,5]; graphite furnace atomic absorption spectrometry (GFAAS) [6,7]; UV/vis spectrophotometry [8]; inductively coupled plasma-mass spectrometry (ICP-MS) [9], inductively coupled plasma atomic emission spectrometry (ICP-AES) [10]. All the available methodologies are based on determination of total gold present in the complex, although the preservation of the species at their original concentration levels prior to analysis is usually essential [11 -13].…”

Section: Introductionmentioning

confidence: 99%

Anodic Stripping Voltammetric Determination of Aurothiomalate in Urine Using a Screen‐Printed Carbon Electrode

Bergamini

Zanoni

2006

Electroanalysis

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This work describes an electroanalytical method for determining gold(I) thiomalate, aurothiomalate, widely used for treatment of reumatoid arthiritis, using a screen-printed carbon electrode (SPCE). Aurothiomalate (AuTM) was determined indirectly at the same electrode by accumulating it first at À 1.5 V vs. printed carbon. At this potential in the adsorbed state, the AuTM is reduced to Au(0), which is then oxidized at two steps at À 0.22 V and þ 0.54 V on SPCE. Using optimized conditions of 60 s deposition time, À 1.5 V (vs. printed carbon) accumulation potential, 100 mV s À1 scan rate, linear calibration graphs can be obtained by monitoring the peak at þ 0.54 V for AuTM in HCl 0.1 mol L À1 from 1.43 Â 10 À6 to 1.55 Â 10 À4 mol L À1 . A limit of detection obtained was 6.50 Â 10 À7 mol L À1, and the relative standard deviation from five measurements of 3.0 Â 10 À5 mol L À1 AuTM is 4.5%. The method was successfully applied for AuTM determination in human urine sample.

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Determination of gold in geological materials by atomic absorption spectrometry after bromine and hydrochloric acid extraction at room temperature

Cited by 15 publications

References 4 publications

Determination of platinum by atomic absorption spectrometry with chromatographic preconcentration from aqueous solutions

Determination of platinum by atomic absorption spectrometry with chromatographic preconcentration from aqueous solutions

Sample Digestion Methods for the Determination of Traces of Precious Metals by Spectrometric Techniques

Anodic Stripping Voltammetric Determination of Aurothiomalate in Urine Using a Screen‐Printed Carbon Electrode

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