Showing papers in "Analyst in 1966"
698 citations
TL;DR: In this paper, the Technicon Auto Analyzer was used for the determination of nitrogen, phosphorus, and potassium in plant materials using a micro-Kjeldahl technique, and the accuracy of these determinations was better than those obtained by other recognised techniques.
Abstract: Methods are described, for use with the Technicon Auto Analyzer, that have been successfully used in the determination of nitrogen, phosphorus and potassium in plant materials. Nitrogen is determined as the indophenol-blue complex on an aliquot of solution after digestion by a micro-Kjeldahl technique. Alternative methods are suggested for the final determination of nitrogen dependent on the range of values expected. The “bias” method is extremely sensitive to small variations in nitrogen levels, and, because of this high sensitivity, the recorder signal-to-noise ratio must be high. Methods are suggested for obtaining a maximum signal-to-noise ratio. Phosphorus and potassium are analysed at the same time on the same sample of ash solution with a single manifold. Phosphorus is determined colorimetrically by the yellow phosphovanadate complex, and potassium by flame photometry by using an internal standard of lithium nitrate. Nitrogen determinations can be carried out at a rate of 40 samples per hour, and phosphorus and potassium together at a rate of 60 samples per hour. The accuracy of these determinations is better than those obtained by other recognised techniques.
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TL;DR: In this paper, a method is described for the determination of residual amounts of anionic surface-active reagents, used as flotation promoters, in mineral flotation liquors, and the method is equally effective for the long carbon chain carboxylates and the anionic non-soapy surfaceactive agents.
Abstract: A method is described for the determination of residual amounts of anionic surface-active reagents, used as flotation promoters, in mineral flotation liquors. The method is equally effective for the long carbon chain carboxylates and the anionic non-soapy surface-active agents. The reagent used is the cationic copper(II) triethylenetetramine complex, which reacts in alkaline solution with anionic surface-active agents to give an adduct that can be extracted into an isobutanol-cyclohexane mixture. The copper associated with the surface-active anion in the extract is determined photo-metrically as the coloured complex using diethylammonium diethyldithiocarbamate. Long chain carboxylates with carbon numbers from C14 to C22, as well as anionic non-soapy surface-active reagents, can be determined in the range 0·2 to 10 p.p.m. The effect of a number of likely interferences has been investigated.
66 citations
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TL;DR: In this paper, the authors present the present state of development of X-ray excitation with radioisotope sources and of relevant methods of non-dispersive energy selection and Xray detection.
Abstract: This paper reviews the present state of development of X-ray excitation with radioisotope sources and of relevant methods of non-dispersive energy selection and X-ray detection. Reduction of interferences arising from absorption, enhancement and particle-size effects is also discussed.The compactness, cheapness and simplicity of the measuring head that result from the use of radioisotope excitation and non-dispersive energy selection are being exploited by portable and “on-stream” analysers now commercially available. The number of applications to ore and alloy analysis is already large and is increasing rapidly. The advantages of radioisotope X-ray spectrometry are less marked and less important in the laboratory where many facilities and alternative techniques exist. Nevertheless, applications for routine single-element determinations are increasing.The basic techniques of excitation and energy selection have been worked out but not yet evaluated for all possible applications. In many of the problems that have been studied, alternative excitation and detection methods have been used but not directly compared. Physical methods for overcoming absorption and enhancement effects have been developed, mainly by analogy with conventional X-ray spectrometry. Suppression of particle-size effects in the analysis of heterogeneous materials remains a problem, especially as fusion techniques for removing the heterogeneity are virtually restricted to the laboratory. There is scope for the development of new techniques for overcoming particle-size effects, especially in “on-stream” analysis.
44 citations
TL;DR: Methods are described for the determination of particulate lead and of tetra-alkyl lead vapour in air, by passing the atmosphere under test through a glass-fibre filter and then through a hydrochloric acid solution of iodine monochloride.
Abstract: Methods are described for the determination of particulate lead and of tetra-alkyl lead vapour in air, by passing the atmosphere under test through a glass-fibre filter and then through a hydrochloric acid solution of iodine monochloride. Tetraethyl lead and tetramethyl lead are collected in this solution by means of their reaction with iodine monochloride to give the corresponding dialkyl lead ions. The lead collected on the filter is extracted with a nitric acid-hydrogen peroxide reagent, and the amount present is determined colorimetrically as lead dithizonate. This may be done automatically with the Technicon Auto-Analyzer, or manually with a comparator and a standard disc.Manual and automatic procedures are also given for the determination of the amount of tetra-alkyl lead collected. The manual method involves reaction of the dialkyl lead ions with dithizone at high pH and matching the colour of the dialkyl lead dithizonate with a standard disc. In the automatic procedure, the dialkyl lead is converted to the inorganic state before reaction with dithizone and colorimetric measurement as lead dithizonate.The methods are designed for the measurement of lead-in-air concentrations down to 0·1 mg of lead per 10 cubic metres of air, with sampling periods of at least 8 hours. A modified method based on a sampling period of half an hour, and having a sensitivity of 0·3 mg of lead per 10 cubic metres, is also described.
40 citations
TL;DR: Experiments on the partition of cyanide in whole blood showed that 5 minutes' exposure resulted in more than 70 per cent.
Abstract: An introduction to the existing methods for the analysis of cyanide is given and some of the limitations to the methods are pointed out.A modification of the Epstein method is described, in which Cavett blood-alcohol flasks are used. This method can be applied to small samples of 2 ml volume containing 0·2 µg of cyanide. By strict control of the conditions it is shown that a high degree of accuracy can be achieved. Interference by heavy metal ions is avoided by using 2 mg of the disodium salt of EDTA per ml of blood. It is therefore suggested that this anti-coagulant should be used when the blood is collected. Experiments on the partition of cyanide in whole blood showed that 5 minutes' exposure resulted in more than 70 per cent. of cyanide being bound to haemoglobin. This value remained unchanged in the presence of a transport inhibitor.
37 citations
TL;DR: In this paper, a method for determining ozone is described which is characterised by the direct recording and automatic determination of ozone within a wide range of concentrations, based on the use of a chemiluminescent solution that is stable, and shows a linear relationship between the light emitted and the ozone concentration.
Abstract: A method for determining ozone is described which is characterised by the direct recording and automatic determination of ozone within a wide range of concentrations. The development of this method is based on the use of a chemiluminescent solution that is stable, and shows a linear relationship between the light emitted and the ozone concentration. A combination of rhodamine B with gallic acid in ethanol is satisfactory in operation and does not itself emit light. The electronic instrumentation used is relatively simple. Other methods of ozone analysis based on this principle meet with much difficulty, owing to the direct oxidation of the chemiluminescent compound. The present method, by contrast, involves the use of gallic acid as an ozone acceptor, and rhodamine B, which remains unchanged during the measurement, as a photon emitter. Observations made with an oscillograph of the light emitted by single bubbles of ozonised air passing through the chemiluminescent solution give valuable information about the responsetime of the system.
TL;DR: In this paper, N-1-naphthylethylenediamine was used to determine mono-hydroxyureas and di-hydroxureas in tissue extracts by diazotising sulphanilamide with the nitrite produced on oxidation.
Abstract: N-Hydroxycarbamates, mono-hydroxyureas and di-hydroxyureas in tissue extracts have been determined by diazotising sulphanilamide with the nitrite produced on oxidation and coupling with N-1-naphthylethylenediamine. Mixtures of hydroxylamine and hydroxamic acids were determined (a), by selective oxidation at pH 3·5 and pH 8·0, and (b), after separation of the components by thin-layer chromatography.
TL;DR: In this paper, a method for the selective extraction of tin(IV) iodide from sulphuric acid solution into toluene was presented, and the metal was finally determined by spectrophotometric measurement of the colour of the complex formed between tin and catechol violet.
Abstract: A method is presented for the selective extraction of tin(IV) iodide from sulphuric acid solution into toluene. Tin(IV) is then returned to aqueous solution by shaking the toluene extract with dilute sodium hydroxide solution. The metal is finally determined by spectrophotometric measurement of the colour of the complex formed between tin(IV) and catechol violet. The method is quick, simple, sensitive and highly selective.
TL;DR: The conditions necessary for extracting the crimson diphenylcarbazone-lead complex into xylene from an aqueous cyanide solution have been examined and a procedure is described for the spectrophotometric determination of lead isolated by means of Diphenylthiocarbazone.
Abstract: The conditions necessary for extracting the crimson diphenylcarbazone-lead complex into xylene from an aqueous cyanide solution have been examined. A procedure is described for the spectrophotometric determination of lead isolated by means of diphenylthiocarbazone.
TL;DR: In this article, the principal C3 to C5 alcohols in potable spirits were determined by direct gas chromatography and the results indicated that the total higher-alcohol content is not characteristic of the type of spirit, but that the proportions of the alcohols to each other fall into distinct ranges typical of the particular spirituous beverage.
Abstract: The determination of the principal C3 to C5 alcohols in potable spirits by direct gas chromatography is discussed. Application of this method to 78 samples of various types of brandy and whisky gives results indicating that the total higher-alcohol content is not characteristic of the type of spirit, but that the proportions of the alcohols to each other fall into distinct ranges typical of the particular spirituous beverage.
TL;DR: In this article, an automatic method for determining manganese in fresh water with the AutoAnalyzer is described, together with details of the analytical system, which is based on a modification of the formaldoxime procedure published by Goto, Komatsu and Furukawa.
Abstract: An automatic method for determining manganese in fresh water with the AutoAnalyzer is described, together with details of the analytical system. The method is based on a modification of the formaldoxime procedure published by Goto, Komatsu and Furukawa,1 which consists in reacting manganese with formaldoxime in alkaline solution, and decomposing any iron formaldoxime formed with EDTA and hydroxylammonium chloride.Aluminium, zinc, copper, iron, calcium, magnesium, chloride and phosphate do not interfere at concentrations above those normally found in natural water in Norway.The capacity of the method is 25 samples per hour, and the standard deviation is 5 µg of manganese per litre.A statistical comparison of the manual persulphate oxidation method with the automatic formaldoxime method indicated that both methods give identical results.
TL;DR: Methods for the examination of intravenous solutions for suspended particles have been investigated and a visual inspection method has been devised, which enables samples to be graded by comparison with reference materials.
Abstract: Methods for the examination of intravenous solutions for suspended particles have been investigated. A visual inspection method has been devised, which enables samples to be graded by comparison with reference materials. For quantitative work, techniques for particle-size analysis with a Coulter Counter have been developed. A survey of all the solutions commercially available in Australia has been made, and limits for the acceptance of such solutions have been proposed.
TL;DR: Neutron-activation analysis was used for the simulataneous determination of iodine and bromine in urine and found the amounts to be of the order of 10–7 and 10–6 g ml–1 of urine, respectively, for normal human beings of different ages.
Abstract: Neutron-activation analysis was used for the simulataneous determination of iodine and bromine in urine. The activated iodine and bromine were separated by radiochemical methods. The 0·46 MeV and 0·55 MeV peak areas of 128I and 82Br, respectively, were measured by means of a multi-channel analyser. The amounts of iodine and bromine were found to be of the order of 10–7 and 10–6 g ml–1 of urine, respectively, for normal human beings of different ages.
TL;DR: The ion exchange method for determining diquat residues in potato tubers has been modified to give a simpler operating procedure and increased accuracy as discussed by the authors, which has been found to be generally applicable to other food crops and to water.
Abstract: The ion-exchange method for determining diquat residues in potato tubers1 has been modified to give a simpler operating procedure and increased accuracy. Experiments on untreated samples with 0·08 to 0·2 p.p.m. of diquat added showed an average recovery of 76 per cent. with a standard deviation of 11 per cent. The method, with minor modifications, has been found to be generally applicable to other food crops and to water. For a 250-g sample, the limit of determination is 0·01 p.p.m.
TL;DR: In this article, an atomic absorption spectroscopy at 3132 A in a nitrous oxide-acetylene flame was used to determine molybdenum in low and high alloy steels.
Abstract: Atomic-absorption spectroscopy at 3132 A in a nitrous oxide-acetylene flame provides a rapid and precise determination of molybdenum in low and high alloy steels. The steel sample (1 g) is dissolved in hydrochloric and nitric acids which are then diluted to volume and sprayed directly into the flame. The observed absorbance is compared with that obtained from a calibration graph prepared from solutions containing known amounts of molybdenum and about the same amount of iron as the steel sample. The method proposed here operates in the range down to 0·2 per cent. of molybdenum and is free from interference from other alloying elements, including tungsten, in steel. The proposed method can be applied to any type of steel by using a single calibration graph.
TL;DR: In this paper, the results of the determination of 27 elements commonly present in titanium dioxide pigments are given, and the total time for a quantitative analysis is approximately 3 hours, and it is possible to analyse up to 8 samples in a working day of 8 hours.
Abstract: Graphite, silver and gold powders have been investigated as conducting media in the analysis of titanium dioxide pigments for trace elements by solid-source mass spectrography. It is concluded that graphite and silver are satisfactory, and that by using both these electrode systems the only elements that cannot be determined are sodium and copper.It has been shown that by using niobium in low concentration as an internal standard, quantitative analysis is possible; the coefficient of variation of the results being approximately 15 per cent. Sensitivity factors for 44 elements relative to niobium in a graphite matrix, and 3 elements relative to niobium in a silver matrix, have been determined. The results of the determination of 27 elements commonly present in titanium dioxide pigments are given. The total time for a quantitative analysis is approximately 3 hours, and it is possible to analyse up to 8 samples in a working day of 8 hours.
TL;DR: In this paper, a method for the determination of boron in soils, sediments and rocks is presented, where the sample is decomposed by a mixture of hydrofluoric and sulphuric acids, and the complex formed between fluoroborate ions and methylene blue is extracted with 1,2-dichloroethane.
Abstract: A method is presented for the determination of boron in soils, sediments and rocks. The sample is decomposed by a mixture of hydrofluoric and sulphuric acids, and the complex formed between fluoroborate ions and methylene blue is extracted with 1,2-dichloroethane. Boron is determined either by visual colour of the blue complex, or by spectrophotometry. The method is rapid and sensitive.
TL;DR: In this article, stationary phases suitable for the separation of 2-methylbutanol (active pentanol) and 3-methyl butanol (isopentanol) are discussed.
Abstract: Stationary phases suitable for the separation of 2-methylbutanol (“active” pentanol) and 3-methylbutanol (isopentanol) are discussed. The most suitable for the determination of these alcohols in potable spirits by direct injection of samples are diethyl tartrate and polyethylene glycol 200. Polyethylene glycol 200 is preferred because other congeners can be determined at the same time. With n-pentanol as an internal standard, 65 samples of cognac brandies, Scotch and other whiskies have been examined on one or other of these stationary phases. The sum of the two pentanol isomers determined separately agrees well with their determination as a single peak on polyethylene glycol 1500. The ratio of the concentrations of the isomers appears to be characteristic of the type of spirit.
TL;DR: In this article, the molybdate ions associated with the phosphate were determined spectrophotometrically at 710 mµ as the green molydenum(VI) complex with 2-amino-4-chlorobenzenethiol in chloroform.
Abstract: Phosphorus as phosphate is determined by an amplification procedure in which the heteropoly acid H3PO4(MoO3)12 is formed and extracted away from excess of molybdate reagent The 12 molybdate ions associated with the phosphate are then determined spectrophotometrically at 710 mµ as the green molybdenum(VI) complex with 2-amino-4-chlorobenzenethiol in chloroform Depending on the procedure used, the effective molar absorptivity for phosphorus is 96,900 or 359,000 The proposed procedure is therefore much more sensitive than previously described methods for phosphorus Amounts of phosphorus down to 0·2 µg (0·008 ppm) may be determined Large excesses of silicon, germanium, arsenic or antimony do not interfere A simple masking procedure obviates any interference from up to a 30-fold excess of tungsten(VI)
TL;DR: In this article, the most suitable conditions for the determination of molybdenum in niobium or tantalum were established, and a study of the effect of other cations and anions was presented.
Abstract: Between 0·006 and 0·06 per cent. of molybdenum can be determined in niobium or tantalum by extracting molybdenum(VI) 8-hydroxyquinolinate from a medium containing fluoride and EDTA as masking agents into butanol at pH 4·5, and atomic-absorption spectroscopy of the extract in a nitrous oxide-acetylene flame at 3132 A without recourse to scale expansion. The most suitable conditions for the determination have been established, and a study of the effect of other cations and anions is presented. Vanadium(V) and chromium(VI) interfere when present in 100-fold excesses, but their interference can be eliminated by the addition of potassium sulphite to the solution before extraction.
TL;DR: In this article, the authors examined some of the factors that affect the determination of carbon dioxide by non-aqueous titrimetry, including absorbent, indicator and titrant.
Abstract: Some of the factors, including choice of absorbent, indicator and titrant, that affect the determination of carbon dioxide by non-aqueous titrimetry are examined experimentally. The results of this examination are used to give a procedure that is recommended for the determination of milligram amounts of carbon dioxide.The method involves absorption of the carbon dioxide in a 5 per cent. v/v solution of ethanolamine in formdimethylamide, followed by titration with standard tetrabutyl ammonium hydroxide in benzene-methanol solution to a visual end-point with thymolphthalein indicator.