A critical evaluation of colorimetric methods for the determination of platinum metals. ii

This paper is the second review of quantitative colorimetric methods for the six platinum metals and covers the period from May, 1953 to March, 1957. Each method is evaluated from the point of view of the optimum concentration range, specified and practical applications to thr assay for platinum metals.     

A critical review of neutron activation and tracer methods for the determination of the noble metals

Neutron activation methods for the seven noble metals are critically reviewed up to December, 1965. The methods deal with the determination of trace impurities in each noble metal as well as traces of noble metals in media such as organic material, fission product and other solutions, ores, alloys, minerals, silica and base metals. The need for confirmatory evidence in the case of such complex materials as ores is emphasized.     

Catalytic kinetic methods for the determination of platinum metals

A review is given of developments over the last two decades in the determination of platinum metals by catalytic kinetic methods.     

A critical review in calibration methods for solid-phase microextraction

Solid-phase microextraction (SPME) was developed to address the need for rapid sampling and sample preparation, both in the laboratory and on-site. Unlike traditional sample preparation methods, SPME is a non-exhaustive extraction technique in which only a small portion of the target analyte is removed from the sample matrix. Therefore, calibration of SPME for quantitative analysis is very important. In this review, we summarized the proposed SPME calibration methods and the characteristics of these methods were discussed.     

A critical review of titrimetric methods for determination of the noble metals-II

Titrimetric methods for palladium, platinum, rhodium, iridium, ruthenium and gold are critically reviewed to the end of 1964. Previous reviews covered the literature to the end of 1957 for the five platinum metals and to mid-1960 for gold.     

Femtochemistry methods for studying the photophysics and photochemistry of halide complexes of platinum metals

Russian Chemical Bulletin - The primary (ultrafast) photophysical and photochemical processes characteristic of the following halogen-containing complexes of platinum group metals were examined:...     

A critical review of methods for obtaining ionic volumes in solution

The various major methods for obtaining individual or “absolute” ionic standard partial molar volumes V‡(ion) from whole electrolyte data in both aqueous and nonaqueous solutions are critically reviewed. A number of undetected errors in previous analyses are pointed out, and it is demonstrated that the reported agreement amongst the various methods in aqueous solution is largely fortuitous. All methods are shown to be unsatisfactory to varying degrees, with the reference electrolyte approach, using an electrolyte such as tetraphenylarsonium tetraphenylborate, appearing to be the least objectionable of those currently available. It is recommended that, subject to future theoretical and experimental developments, the assumption that, at 25‡C: - V‡(Ph₄As⁺) - V‡(BPh₄) = 8 cm³-mol^-1, or its equivalent: V‡(Ph₄P⁺) - V‡(BPh ₄ ^- ) = 2 cm³-mol^-1 be used in all solvents.     

A review of methods for synthesis of nanostructured metals with emphasis on iron compounds

Synthesis of metal nanoparticles with specific properties is a newly established research area attracting a great deal of attention. Several methods have been put forward for synthesis of these materials, namely chemical vapor condensation, arc discharge, hydrogen plasma—metal reaction, and laser pyrolysis in the vapor phase, microemulsion, hydrothermal, sol-gel, sonochemical, and microbial processes taking place in the liquid phase, and ball milling carried out in the solid phase. The properties of metal nanoparticles depend largely on their synthesis procedures. In this paper the fundamentals, advantages, and disadvantages of each synthesis method are discussed.     

Oxidimetric methods for the volumetric estimation of sulphite

1. The use of permanganate, ceric sulphate, and dichromate for the estimation of sulphite has been reinvestigated, although these reagents have heen discarded as useless by earlier investigators. By using catalysts under controlled acid concentration, we have been able to develop conditions for the quantitative oxidation of sulphite to sulphate at room temperature by any one of these oxidizing agents, avoiding the formation of dithionate. Copper sulphate and iodine monochlonde have been found useful as catalysts with potassium permanganate and dichromate; but only iodine monochloride with ceric sulphate. 2. Sodium sulphite is also oxidized quantitatively to sulphate at room temperature, when added to excess of sodium vanadate solution containing 5 to 6N hydrochloric acid and iodine monochloride as catalyst.     

Atomic spectrometric methods for the determination of metals and metalloids in automotive fuels - A review

Gasoline, diesel, ethanol and more recently also biodiesel are the four types of fuel used for automobile, truck and other transportation vehicle. The presence of metallic and metalloid species in automotive fuels is undesirable, except in the form of additives in order to improve specific characteristics of the fuel. Metallic or metalloid elements may derive from the raw product, such as nickel and vanadium in petroleum-based fuel or phosphorus in biodiesel, or they may be introduced during production and storage, such as copper, iron, nickel and zinc in case of petroleum-based fuel and alcohol or sodium and potassium in the case of biodiesel. The most famous additive to fuel is undoubtedly lead, the use of which has been banned or drastically reduced now in many countries of the world. The problems related to the trace element content may be economic, such as fuel degradation and poisoning of automotive catalysts, and/or environmental, such as the emission of metal compounds to the atmosphere. The analytical methods that have been developed for metal and metalloid quantification in automotive fuel are reviewed in this article. The main atomic spectrometric techniques used for trace metal and metalloid determination in fuels, particularly atomic absorption spectrometry with flames, graphite furnaces and with chemical vapor generation, and inductively coupled plasma coupled with optical emission and mass spectrometry are presented, including the different sample preparation procedures proposed for these techniques.     

The Microchemistry of the platinum metals

Summary A method is outlined for the separation and determination of small amounts of osmium, iridium and platinum. Osmium and platinum are determined colorimetrically, and iridium is determined by titration. The procedure gives reproducible results, and provides a convenient method for the determination of each of the elements.

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Zusammenfassung Eine Methode zur Trennung und Bestimmung kleiner Mengen Osmium, Iridium und Platin wurde beschrieben. Osmium und Platin werden kolorimetrisch bestimmt, Iridium maßanalytisch. Das Verfahren gibt reproduzierbare Ergebnisse und eignet sich zur Bestimmung jedes der genannten Elemente.

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Résumé On recommande une méthode pour la séparation et le dosage de petites quantités d'osmium, d'iridium et de platine. On dose par colorimétrie l'osmium et le platine et par titrage l'iridium. Le procédé donne des résultats reproductibles et fournit une méthode appropriée pour le dosage de chacun des éléments.

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In honour of the 70th birthday ofFritz Feigl.     

A comparison of methods for the determination of platinum in ores

Fire-assay and wet-extraction methods of determining platinum in ores have been evaluated. The fire-assay procedure using lead as a collector was used in combination with flame and flameless atomic-absorption, emission spectroscopy and X-ray fluorescence. In this last method flattened silver beads were analysed directly, whereas for the other methods the beads were dissolved in aqua regia and the solutions made up with concentrated hydrochloric acid before analysis. The wet procedures involved treatment of the ores with acids and subsequent analysis by flame atomic-absorption or by spectrophotometry after treatment with tin(II) chloride. Chromatographic, ion-exchange and solvent-extraction procedures were used to isolate platinum from base metals, the other platinum metals and gold. Results for each ore by fire assay-flame atomic-absorption, fire assay-emission spectroscopy, and wet extraction combined with spectrophotometry, showed no difference at the 99% confidence level. X-Ray fluorescence and flameless atomic-absorption results tended to be high and low respectively. The most precise method was wet extraction followed by spectrophotometric determination. Emission spectroscopy and X-ray fluorescence generally yielded the poorest precision. Wet-extraction methods were time-consuming and since no advantage was gained in accuracy over the fire-assay methods, a combined fire assay-flame atomic-absorption system was the preferred method of analysis.     

DNA methods: critical review of innovative approaches

The presence of ingredients derived from genetically modified organisms (GMOs) in food products in the market place is subject to a number of European regulations that stipulate which product consisting of or containing GMO-derived ingredients should be labeled as such. In order to maintain these labeling requirements, a variety of different GMO detection methods have been developed to screen for either the presence of DNA or protein derived from (approved) GM varieties. Recent incidents where unapproved GM varieties entered the European market show that more powerful GMO detection and identification methods will be needed to maintain European labeling requirements in an adequate, efficient, and cost-effective way. This report discusses the current state-of-the-art as well as future developments in GMO detection.     

Selective complexing agents for the trace enrichment of platinum metals

Summary N,N-Dialkyl-N-benzoylthioureas act as selective complexing agents for the enrichment of platinum metals even from strongly interfering matrices. In combination with chromatographic separation techniques of GFAAS as detection method metal determinations in the g- and ng/kg range are possible. A review of the investigations so far been carried out is given.     

Sulphur dioxide complexes of the platinum metals

Summary The structural, chemical and theoretical aspects of the coordination chemistry of sulphur dioxide complexes of the platinum metals have been reviewed. A detailed evaluation of the analogy between nitric oxide and sulphur dioxide ligands has been made, and it has been concluded that although the structural properties of complexes of these ligands are closely related, their oxidative-addition and oxidation reactions differ in many important respects.Reprints of this article are not available.     

Sample preparation methods for subsequent determination of metals and non-metals in crude oil—A review

In this review sample preparation strategies used for crude oil digestion in last ten years are discussed focusing on further metals and non-metals determination. One of the main challenges of proposed methods has been to overcome the difficulty to bring crude oil samples into solution, which should be compatible with analytical techniques used for element determination. On this aspect, this review summarizes the sample preparation methods for metals and non metals determination in crude oil including those based on wet digestion, combustion, emulsification, extraction, sample dilution with organic solvents, among others. Conventional methods related to wet digestion with concentrated acids or combustion are also covered, with special emphasis to closed systems. Trends in sample digestion, such as microwave-assisted digestion using diluted acids combined with high-efficiency decomposition systems are discussed. On the other hand, strategies based on sample dilution in organic solvents and procedures recommended for speciation analysis are reported as well as the use of direct analysis in view of the recent importance for crude oil field. A compilation concerning sample preparation for crude oil provided by official methods as well as certified reference materials available for accuracy evaluation is also presented and discussed.