Silver Wool Research Articles

Comparative studies on trace metal levels in marine biota I. Mercury in marine organisms from western Italian coast, the strait of Gibraltar and the North Sea

The mercury level has been determined in the edible part of 36 marine species (867 specimens) caught from 1975 to 1976 mainly close to the Western Italian coast, the Strait of Gibraltar and in some selected regions of the North Sea. Sample pretreatment was performed after careful preparation by nitric acid pressure decomposition of frozen stored subsamples using up to 2.5 g fresh weight (FW). The analytical method was automated cold vapour atomic absorption spectrophotometry after preconcentration on silver wool. Accuracy and precision of the method was checked by interlaboratory intercomparisons and intralaboratory test measurements of repeatability and also the use of Standard Reference Materials. The total mercury (HgT) values obtained ranged from 20 μg/kg FW to ⩾2,000 μg/kg Fresh weight for the Mediterranean Sea and for some pelagic species showed significantly elevated mercury values compared with organisms from the Atlantic and North Sea. For benthic organisms, however, probably due to dominating local influences, a similar behaviour has not been observed. Evaluation of body weight/mercury concentration ratios showed significant correlations for several species differing between distinct locations.

Mass-spectrometric study of the thermal pyrolysis of tetrasulphur tetranitride over quartz wool and silver wool

Mass-spectrometric techniques have been used to identify the pyrolysis products of S4N4 vapours passed over quartz wool and silver wool at 80–400 °C. Tetrasulphur tetranitride was volatilized from solid samples at 60–80 °C in a heated tube and passed into a second reaction tube packed with quartz or silver wool heated to 80–400 °C. The products passing from the reaction tube are examined using modulated molecular-beam techniques in conjunction with measurements of the mass-spectrometric appearance potentials, low-energy electron-impact mass spectrometry, and phase-angle spectrometry. The major product at ca. 200 °C is S2N2, accompanied by smaller amounts of S3N3 and S4N2. At higher temperatures (>300 °C) S2, SN, and N2 become the major pyrolysis products. The results are examined in terms of their implications for the synthesis of (SN)x from S2N2 and S4N4.

Preconcentration on Silver Wool of Volatile Organo-Mercury Compounds in Natural Waters and Air and The Determination of Mercury by Flameless Atomic Absorption Spectrometry

Abstract Preconcentration of volatile organo-mercury and metallic mercury on silver microcolumn is particularly suitable for the determination in air and water samples. The microcolumn is coupled to a cell for mercury determination by f.a.a.s. With this technique, down to 1 ng of mercury can be determined with a good precision (¶15%).

Ein schwefelselektiver detektor für die flüssigkeits-chromatographie auf konduktometrischer basis

A conductometric procedure for the determination of sulfur in organic solvents is described. The sample is nebulized by a stream of oxygen and the sulfur dioxide produced by combustion at 1300° C is swept into an absorption solution, the increase in conductivity being recorded. The working range is about 1–100 mMol Sl -1 and the response time about 30s. Interferences of N, P and halogens are discussed. The halogen interference can be eliminated with silver wool, but the sensitivity for sulfur is then reduced.

The determination of mercury at picogram/litre levels in water with a microwave-induced argon plasma emission system

The need for accurate determinations of mercury at sub-ng 1-1 levels in sea water has led to the development of a microwave-excited argon plasma emission method. The system utilizes an amalgamation stage where mercury released from water samples by tin(II) chloride reduction is amalgamated onto silver wool. The wool is subsequently heated and the mercury thus released is flushed by argon into a plasma where it is excited. The emission signal thus produced results in a detection limit of 3·10-17 g and an analytical range of 1·10-14– 1·10-7 g.

Atomic absorption determination of elemental mercury collected from ambient air on silver wool

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAtomic absorption determination of elemental mercury collected from ambient air on silver woolS. J. Long, D. R. Scott, and R. J. ThompsonCite this: Anal. Chem. 1973, 45, 13, 2227–2233Publication Date (Print):November 1, 1973Publication History Published online1 May 2002Published inissue 1 November 1973https://doi.org/10.1021/ac60335a032RIGHTS & PERMISSIONSArticle Views196Altmetric-Citations59LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (801 KB) Get e-Alerts Get e-Alerts

Determination of carbon-14, tritium, or sulfur-35 after combustion of an organic sample at a system of nozzles

Compounds labeled with 14C, 3H, or 35S are combusted at a system of nozzles. Samples from the milligram range up to 200 mg can be oxidized completely by this technique without individual control for vaporization. Samples exceeding 200 mg can also be combusted, but the gasification of the sample has to be regulated according to the size of the flames at the nozzles. The combustion products are collected in a trap containing methanol, ethanolamine, resp. toluene at −20 °C (for 35S at −70 °C). Activity is counted with a liquid scintillator spectrometer. Various combustion products reduce the counting efficiency and cause a quenching effect. The dependence of this effect on the amount of heteroatoms was determined for 14C, 35S, and 3H. Quenching of halogens, which is especially severe, could be eliminated by silver wool at 600 °C. Finally, it is shown that the efficiency of the phosphor is decreased remarkably when it is exposed to sunlight and air for a longer time.

Silver granules as an absorbent of halogens and oxides of sulphur

A preparation of silver granules has been used as an absorbent for halogens and sulphur. Its absorptive capacities for halogens and for sulphur were determined at various temperatures. The capacities are favorably compared with that of electrolytic silver wool. Having a granular form, the material is more conveniently used than electrolytic silver wool, and is applicable to the determination of carbon-hydrogen, halogens, sulphur or oxygen.

A new type of combustion tube for carbon-hydrogen determination by the ?rapid combustion method?

Using the “empty tube” technique based on earlier work ofIngram, a new type of combustion tube has been designed. The horizontal combustion tube is maintained. Halogen and sulphur oxides are absorbed by “electrolytic” silver wool. The nitrogen oxides are absorbed by manganese dioxide in a slightly modified absorber.

Microdetermination of halogens in organic compounds

Safford andStragand have described a method for the microdetermination of halogens using a silver-gauze-absorbent. The procedure is very simple, but unfortunately the results are not precise enough to enable the method to be recommended. The method has been modified. The sample is burned in an atmosphere of oxygen using a platinum catalyst, and the halogen formed is quantitatively absorbed on electrolytic silver wool in a special absorption-funnel, which is then weighed. The method is precise and accurate (standard deviation of the results: 0.12 per cent). Silver wool presents a much greater surface than silver-gauze and absorbs on an average 160 mg of chlorine per gram, i. e. forty or fifty times as much as a piece of silvergauze of the same dimensions. The charge in an absorption-funnel therefore has a long life for routine analysis of halogen compounds. The operating temperature range of the silver-wool is wide, so that precise control is not neccessary. The method compares favourably in accuracy, precision and simplicity with established methods.

The micro-determination of carbon and hydrogen in fluorine-containing organic compounds

The sample is burned in a silica combustion tube, using a 4 ml per minute oxygen stream. Oxidation of the combustion products is completed by passing them over a platinum contact heated to 750°C, after the manner ofFriedrich. Silver wool at the same temperature removes sulphur and halogens, including the fluorine from any hydrogen fluoride produced, and granular sodium fluoride at about 270°C is used to absorb silicon tetrafluoride.