Analysis of cement and cement raw meal by atomic absorption spectrophotometry using a new fusion agent

A new fusion agent is proposed for the analysis of cement and cement raw meal using AAS. In the described method, 0.8 g of the fusion agent, consisting of equal portions of oxalic acid, lithium carbonate and lithium tetraborate, was mixed with 0.2 g of the sample, and the mixture was fused for 10 min at 925 degrees C in a platinum crucilbe. The fusion cake was dissolved with dilute hydrochloric acid (1 + 10) and diluted to 500 ml for the determination of Si, Al, Fe, Ti, Na and K expressed as SiO(2), Al(2)O(3), Fe(2)O(3), TiO(2), Na(2)O, and K(2)O respectively. For the determination of Ca and Mg (expressed as CaO and MgO respectively), 10 ml of the previous sample solution were mixed with 4 ml of 6% (m/v) lanthanum nitrate solution and the solution was diluted to 100 ml. The method was found to have good accuracy and precision. The time required to determine the eight elements was around 80 min for each sample.     

New method for the determination of pentachlorophenol by atomic absorption spectrophotometry

A new application of atomic absorption is reported for the determination of pentachlorophenol. The method is based on solvent extraction into nitrobenzene of the ion-pair formed between tris(1,10-phenanthroline) iron(II) and the anion of pentachlorophenol, and the subsequent determination of the iron concentration m the extract by atomic absorption at the 2483 A iron line.     

Determination of thallium by atomic absorption spectrophotometry

Summary The determination of thallium by atomic-absorption Spectrophotometry is described. Many substances interfere with the direct analysis of thallium under the conditions chosen. However, these interferences can be overcome by adding a lithium, potassium, or sodium buffer (5000 ppm). In this way the deviations caused by foreign substances can be reduced to less than ten per cent. Under the same conditions the effect of organic solvents has been studied.

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Zusammenfassung Die Bestimmung von Thallium mit Hilfe der atomaren Absorptionsspektrophotometrie wird beschrieben. Die direkte Bestimmung von Thallium wird im allgemeinen durch viele Fremdionen in höheren Konzentrationen gestört. Durch Verwendung eines Li-, K-, oder Na-Puffers (5000 ppm) können die Störungen auf weniger als 10% herabgesetzt werden. Unter den gleichen experimentellen Bedingungen wird die Wirkung von organischen Lösungsmitteln untersucht.

     

Determination of nonmetals by atomic absorption spectrophotometry

Inorganic anions and organic compounds are determined using conventional atomic absorption apparatus. Several methods are studied in which the desired compound either limits or interferes with the determination or absorption of a metal. A direct relationship is obtained between the absorption by the metal and the amount of substance sought. Substances determined include orthophosphate, sulfate, iodide, sulfide, iodate, glucose, protein, 8-hydroxyquinoline, ethylenediaminetetraacetic acid, and ammonium pyrrolidine dithiocarbamate.     

Determination of vanadium by atomic absorption spectrophotometry

Methods for the determination of vanadium, in the range 0.5–100 mg/l, by atomic absorption spectroscopy in an oxy-acetylene as well as in a nitrous oxideacetylene flame are presented. For use with oxy-acetylene flames, vanadium is extracted as vanadium cupferrate into a mixture of methyl isobutyl ketone and oleic acid (78:22, v/v) and the organic phase is aspirated to the flame. The sensitivity is 0.7 mg/l of vanadium in the organic phase. For nitrous oxide-acetylene flames, an aqueous solution of vanadium is aspirated directly. The sensitivity is further improved by the use of methyl isobutyl ketone, the addition of Al³⁺ and diethylene glycol diethyl ether. Many potential interferences were examined and methods to overcome those found are given.     

单纯形最优化法在氢化物原子吸收分析中的应用

单纯形法^[1-7]是一种动态寻优方法。它能在交互作用复杂，因素较多的场合使用，对实验有全面优化的效果，克服了单因素优选法无法考虑各因素间的交互影响、 准确性低、工作量大的缺点。它能在实验次数较少的情况下，快速的找出接近最佳分析条件组合，综合优化性能指标较小。     

Blood lead by furnace-Zeeman atomic absorption spectrophotometry

A quick, accurate graphite furnace-atomic absorption spectrophotometric method for blood lead in the range 5 to 50 μg/dl was evolved by adding a 0.100-ml blood sample to 0.400 ml of aqueous 0.2% (w/v) Triton X-100, followed by the addition of 0.500 ml of Type I water. After shaking, a 10-μl aliquot was inserted into a pyrolytically coated graphite furnace tube in a Zeeman atomic absorption spectrophotometer. The method was validated by the method of standard additions, by mixing bloods of known lead content in known ratios, by two independent methods of isotope dilution/mass spectrometry, and by two independent methods involving anodic stripping voltammetry. Mixing bloods of known lead content in defined ratios is an acceptable substitute for the standard additions method.     

The determination of gold by atomic absorption spectrophotometry

Gold can be isolated from most other elements other than the platinum metals by the extraction of iron(II) 1,10-phenanthroline tetrabromoaurate in chloroform. After isolation gold can be determined in the organic solvent by atomic absorption spectroscopy or colorimetrically by decomposition of the complex and determination of the iron by bathophenanthroline.     

The determination of selenium by atomic absorption spectrophotometry

The problems involved in the determination of selenium by atomic absorption spectrophotometry are discussed. A practical method is described for which the sensitivity is approximately 1 p.p.m. Such concentrations can be determined in organic samples, but with mineral samples the preliminary treatment renders the procedure unsuitable for concentrations lower than 50 p.p.m. in a sulphide ore.     

The determination of uranium isotopes by atomic absorption spectrophotometry

The uranium isotopes, ²³⁵U and ²³⁸U, can be determined easily by atomic absorption techniques, employing relatively inexpensive and unsophisticated equipment. A water-cooled hollow-cathode discharge tube was used as an absorption tube. It was found that large amounts of uranium atoms, in the ground state, were produced by the discharge in the tube. Thus the inherently weak uranium resonance radiation coming from. an emission source and passing through the absorption tube was absorbed. For the first time in an atomic absorption technique, samples and related standards were used in the emission source instead of an absorption source, and a high degree of accuracy and precision was obtained. Valid results were also obtained by conventional techniques — that is, the samples and related standards were employed in the absorption source.     

Determination of magnesium in iron by atomic absorption spectrophotometry

An atomic absorption spectrophotometric method for the determination of 0.001–0.10% magnesium in irons has been proposed. After suitable dissolution of the sample, 1500 p.p.m. of strontium is added to suppress aluminium interference and the solution is atomised in an atomic absorption spectrophotometer. The method is rapid, has high sensitivity, is free from interference and no preliminary separations are required.     

Trace elements in marine waters by atomic absorption spectrophotometry

Trace elements of interest in sea water fall into two well-defined categories. Strontium, lithium, and rubidium are ideally suited to determination by atomic absorption spectrophotometry since minimal sample preparation is required and standard equipment may be utilized; standardization of techniques by which large batches of samples may be rapidly and accurately processed, is important. The transition elements are present in significantly lower concentrations and in complex, and largely unknown, chemical forms; pre-concentration is vital, Solvent extraction can also provide a crude differentiation between total and extractable fractions.     

Microdetermination of α-amino acids by colorimetry and atomic absorption spectrophotometry

The present work describes two simple, rapid, sensitive, and reliable methods for the determination of α-amino acids after conversion to their corresponding Cu(II) chelates. In the first method, the copper complex is treated with cyanide and phosphomolybdic acid in HCl medium followed by colorimetric measurement of the molybdenum blue produced. In the second method, the absorbance of the copper chelate is directly recorded on aspiration in the atomic absorption spectrophotometer. A variety comprising 9–10 α-amino acids were successfully determined by each of the two methods with average errors not exceeding ±0.30 and ±0.18%, respectively.     

Analysis of siliceous materials and coal by atomic absorption spectrophotometry with fusion for sample decomposition

The oxalic acid-lithium carbonate-lithium tetraborate (1:1:1) fusion agent proposed previously for cement analysis is applied to determine the composition of various siliceous samples including granite, clay, flyash, sand and silica fume. For samples with silica content higher than 70%, the sample size had to be reduced from 0.10 to 0.01 g and a recovery factor was needed in silica determination to account for the precipitation of silica during acid dissolution. Attempt has also been made to determine the major metallic elements in coal by fusion directly without the ashing procedure, and the results obtained were good. Further, the ash content of coal was proposed to be determined by establishing a relation between the ash content and the sum of the concentrations of four major oxides (i.e. the oxides of Si, Al, Fe and Ca), and the proposed method is accurate and is time saving compared with that determined by direct ashing at 800 degrees C.     

Signal and data processing for atomic absorption spectrophotometry

The state-of-the-art of signal and data processing techniques for atomic absorption spectrophotometry is described and discussed. Aspects of optical and atomizer design of greatest importance for providing the best signal to noise S/N ratio and minimum curvature are summarized. In background corrected systems, amplifier gain and time constants must be carefully matched, especially for transient signals. A method is given for calculating the sampling time of peak search systems. Methods of signal averaging are described and the importance of precision calculations is stressed. The correct sequence of readings for calibration is discussed. The causes of curvature are shown for simple and complex curves and methods of correction are compared. Other desirable functions are calculation of sensitivity and detection limit, error warnings and external data output facilities.     

The determination of manganese in iron and steel by atomic absorption spectrophotometry

A procedure is described for the determination of 0.001–2% of manganese in low and high alloy irons and steels by atomic absorption spertrophotometry. The sample is dissolved in phosphoric-sulphuric acid and atomised in an atomic absorption spectrophotometer. The method is rapid, free from interferences, preliminary separations are not required and results obtained on standard samples agree closely with stated certificate values.