The determination of losses in the fire assay of gold: Part I. Cupellation and parting losses

The losses in the cupellation and parting procedures of the fire assay for gold were evaluated with simulated buttons of lead foil. Variation in weight of lead, silver-gold ratio, and cupel size did not affect gold losses. Removal of cupel material from the bead increased the gold loss. Flattening the bead and increasing the parting acid strength reduced the gold losses somewhat. No evidence of losses by volatilization was observed.     

电位滴定法测定火试金得到的金银合粒中的银

本文研究了用自动电位滴定仪测定外购铜物料样品中经火试金熔炼、富集、灰吹后得到的金银合粒中银的方法。金银合粒用硝酸溶解后在自动电位滴定仪上用硫氰酸钾标准溶液滴定银量,选择了仪器的测定条件,考察了溶液酸度、共存元素对测定的干扰。方法相对标准偏差为1.34％～3.62％,测定结果与硫氰酸钾手工滴定法和减杂法相一致。方法的准确度和精密度均能满足分析需要,具有较强的实用性和推广价值。     

The double radio-isotope derivative technique for the assay of drugs in biological material: Part II. The simultaneous determination of opipramol and its deshydroxyethyl metabolite

The neuroleptic drug opipramol and its deshydroxyethyl metabolite can be determined simultaneously in the same biological sample. Known amounts of ¹⁴C-labelled opipramol and ¹⁴C-labelled metabolite are added to the sample to serve as internal standards. After suitable extraction, both compounds are acetylated by ³H-labelled acetic anhydride. Together with μg-amounts of carrier compounds, the O-acetyl derivative of opipramol and the N-acetyl derivative of the metabolite are purified and separated by two-dimensional thin-layer chromatography. Each of the derivatives is isolated and counted for ¹⁴C-and ³H-activity. The ¹⁴C-activities recovered serve to determine the overall yield of the opipramol and metabolite, and to convert the measured ³H-activity to 100 % theoretical yield. From analyses of standard samples, the specific ³H-activities of the acetyl derivatives were calculated, and these values were used to convert the measured ³H-activities from biological samples to concentrations of original opipramol and metabolite. For both compounds the standard deviations of blank samples were ±1 ng ml^?1. For concentrations up to 100 ng ml^?1 the standard deviation was ±3 ng ml^?1.     

Single-point titrations: Part II. Experimental determination of bases

An acid—base mixture is described which has linear pH response when titrated with strong base. The concentrations of the separate components in the mixture are given. Determinations of bases in the tange 0.05 M—0.25 M with a relative standard deviation of less than 0.5 % are reported. The method of preparing the mixture as well as some interferences of high salt concentrations in the sample are discussed.     

火试金法配料过程自动化的探索和应用

火试金法中配料方式采用的是传统的人工配料,针对人工配料方式的不足,设计了一款自动化程度较高的自动配料机,通过对配料机的准确性、效率及可靠性实验,结果表明配料机检测称量误差在±0.2 g以内,效率为人工配料的2~3倍,检测结果与人工配料的相一致。与此同时,应用此设备改善了工作环境,避免了人为失误造成的检测质量问题,降低了复检率,为企业降低了成本,提高了效益,在业内具有广泛应用前景。     

火试金重量法与AAS湿法结合测定砂金矿中金的含量

砂金矿中二氧化硅和金的含量较高,本文用传统的火试金重量法与AAS湿法相结合来测定砂金矿中的金含量,用以得到较为精确的结果。本文用科学的配料方法,调节好熔渣的硅酸度,得到品质更好的熔渣与铅扣。再通过二次补正收集分散在熔渣中的金,之后进行三次补正收集灰皿中残留的金含量,然后用原子吸收光谱—AAS湿法测定三次补正得到的金银合粒与分金液中金的含量,从而得到更精确的结果。此方法操作简便、适用性广、精密度与准确度较高。通过加标测试此方法金的回收率在99.2%～100.3% 之间,金的相对标准偏差(RSD)在0.24%～0.6%之间。     

An experimental evaluation of neutron activation, wet assay and fire assay methods of determining gold in ores

The errors associated with fire assay, wet extraction and neutron activation methods are evaluated, the accuracy and precision of these methods are compared, and a method of determining chemical recovery in the activation determination of gold in ores and concentrates is presented.     

On the adsorption of aliphatic alcohols on gold Part II

The adsorption of a wide selection of aliphatic alcohols on a polycrystalline gold electrode from 0.02 M NaF solution was studied using the tensammetric method. The thermodynamic data presented for the primary and secondary alcohols show close correlations between structure and Gibbs energy of adsorption. The standard Gibbs energy of adsorption increases with the chain length of primary alcohols by 3.5 kJ/mol for every additional C atom and by 2.7 kJ/mol in the case of secondary alcohols. The discussion of the data includes results presented previously and shows new aspects for the interpretation of the kinetic data of the anodic oxidation of these alcohols in alkaline solutions. This is supported by the tensammetric data obtained for some typical alcohols and the gold electrode in an electrolyte solution of 0.04 M KOH.     

The determination of metals in petroleum samples by atomic absorption spectrometry : Part II. Determination of nickel

Some atomic absorption characteristics of xylene solutions of eight organometallic compounds of nickel in air—acetylene and nitrous oxide—acetylene flames are described. Different absorbances from various nickel organometallic compounds were observed; these differences were not eliminated by using the nitrous oxide—acetylene flame. Serious errors may arise when different organometallic compounds are used for calibration in the determination of nickel in xylene solutions of various petroleum samples. These errors are much less pronounced when nickel is determined by a standard addition technique. The effects of different sample matrices are discussed.     

The accurate determination of gold and silver in ores and concentrates by wet-chemical analysis of the lead assay button

Hydroquinone or formic acid can be used as reductant for the quantitative precipitation of gold in the lead perchlorate solution obtained after the lead assay button has been parted with perchloric acid. Silver chloride can be completely precipitated by dilution and overnight standing of the parting solution, thus both gold and silver can be isolated by filtration for the final measurement. The proposed lead-wet chemical method was successfully applied to ores, concentrates, dusts, etc.     

Simultaneous determination of carbon,hydrogen, and nitrogen. Part II

Summary An analytical procedure is described which allows the simultaneous determination of carbon, hydrogen, and nitrogen in solid organic materials by gas-volumetric techniques. The accuracy is comparable to that obtained with the more conventional methods.On a routine basis, six to ten complete sets of determinations can be made per 8-hour day. The exact number will depend upon the samples being analyzed and the analyst's skill.

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Zusammenfassung Ein Verfahren zur gleichzeitigen gasvolumetrischen Bestimmung von Kohlenstoff, Wasserstoff und Stickstoff in festen organischen Verbindungen wird beschrieben. Die Genauigkeit ist mit jener der üblichen Verbrennungsverfahren vergleichbar.Bei Serienarbeit können in 8 Stunden sechs bis zehn vollständige Analysen ausgeführt werden. Die genaue Zahl hängt von der Art der Proben und von der Geschicklichkeit des Analytikers ab.

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Résumé On décrit un procédé analytique permettant de doser simultanément le carbone, l'hydrogène et l'azote dans les corps organiques solides au moyen de techniques fondées sur une mesure de volume gazeux. La précision est comparable à celle que l'on obtient avec les méthodes plus conventionnelles.On peut réaliser six à dix séries complètes de dosages en une journée de 8 heures, dans un travail de routine. Le nombre exact dépendra des échantillons que l'on analyse et de l'habileté de l'analyste.

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Part I, UCRL-5134, Chem. Abstr.52, 16 118c (1958).

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This work was performed under the auspices of the U. S. Atomic Energy Commission.     

High speed analysis in packed columns. Part II. Some guidelines and procedures for time optimisation

Summary The work described in Part I has been extended to show that the basic equation derived therein can be reduced to allow a direct analytical solution. For convenience, solution by this technique is termed DAMAT-X (Direct Approach Minimising Analysis time based on X) to distinguish it from solutions obtained by the technique in Part I, named here simply DAMAT. An additional advantage of the reduced equation is that some solutions are readily available by inspection and this feature is illustrated diagrammatically. Finally it is indicated how DAMAT-X can be used as the basis for assessing the accuracy of other techniques based on the (h/ū) group, but which require less data for approximating to minimising conditions.     

The application of strongly reducing agents in flow injection analysis: Part 1. Chromium(II) and vanadium(II)

Many reagenst cannot easily be applied in quantitative analysis, because of their instability under atmospheric conditions. When such reagents are prepared in a flowing stream, their applicability is very promising; for example, in flow injection analysis, a reagent need be stable only for 20–30 s. The application of chromium(II) and vanadium(II) in flow injection analysis is described. Nitrate and nitrile can be determined in the concentration range 5 × 10^?5?5 × 10^?3. Calibration graphs show good linearity.     

The application of strongly reducing agents in flow injection analysis : Part 3. Vanadium(II)

The application of vanadium(II) as a powerful reducing reagent in flow injection analysis is described. Results are presented for the determination of various organic and inorganic substances. With spectrophotometric detection, based on the absorption by vanadium(II)-EDTA at 350 nm, limits of determination were about 5 X 10^?5 mol 1^?1. Nitrate, nitrite and hydroxylamine were measured with amperometric detection. The limit of determination was about the same as with spectrophotometric detection. In a slightly acidic medium, hydrazine could be determined with the amperometric detector, with a limit of determination of about 10^?4 mol l^?1. By coupling an ammonia detection device to the reduction system, the percentage conversions of nitrate, nitrite and hydroxylamine to ammonia were shown to be 26%, 54% and 47%, respectively.     

The application of thiosalts in analysis : Estimations based on decomposition of thiosalts Part C. Estimation of gold,platinum and antimony

The general method of forming and then decomposing the thiosalts has been applied to the gravimetric estimation of gold, platinum and antimony. In the case of gold and antimony the metals are weighed as Au₂S₃ and Sb₂S₃ respectively, while in the case of platinum, the precipitate of platinum sulphide is ignited and weighed as metal.