A new selective reagent for the spectrofluorometric determination of beryllium

The fluorescence properties of the beryllium and aluminum complexes with 2, 4-dioxo-4-(4-hydroxy-6-methyl-2-pyrone-3-yl) butyric acid ethyl ester (Ligand) were studied and optimal conditions for their fluorometric determination were established. Beryllium can be determined in the linearity range of 0.5–2.0 μg/ml and aluminum 0.5–1.5 μg/ml. The effect of diverse ions on the determination of beryllium is discussed.A simple procedure for the fluorometric determination of beryllium in human blood plasma in the concentration range of 5–50 μg Be/ml is described.     

Atomic fluorescence spectroscopy of beryllium

The atomic fluorescence of beryllium has been observed. A high-intensity beryllium hollow-cathode lamp was used as the source. Oxy-acetylene and nitrous oxide-acetylene flames were studied. A newly designed burner assembly for nitrous oxide-acetylene flames used for atomic fluorescence studies is described. The sensitivity for beryllium at 2349 Å was 10 p.p.m. in the oxy-acetylene flame and 0.5 p.p.m. in the nitrous oxide-acetylene flame. The analytical calibration curves for both flames are presented. No significant interference was found from the cations studied. Some anionic interferences were removed by EDTA. The effects of some organic solvents were investigated.     

The determination of beryllium in geological and industrial materials by atomic-absorption spectrometry after cation-exchange separation

A method is described for the determination of beryllium in geological and industrial samples. After dissolution of the sample in mineral acids, beryllium is separated from the matrix elements by chloroform extraction of its acetylacetonate from a solution of pH 7 containing ascorbic acid and EDTA. Beryllium is separated from the organic extract and from co-extracted aluminium by means of a column of the strongly acidic cation-exchanger Dowex 50; beryllium is adsorbed from a medium consisting of 60 % (v/v) tetrahydrofuran, 30 % (v/v) chloroform and 10 % (v/v) methanol containing hydrochloric acid, aluminium is removed with 0.4 M oxalic acid and after elution with 6 M hydrochloric acid, beryllium is determined by atomic-absorption spectrometry with a nitrous oxide-acetylene flame. The method was used to determine p.p.m. and sub-p.p.m. quantities of beryllium in geochemical reference materials, U₃O₃ and yellow cake samples, and manganese nodules.     

Micelle-mediated extraction for simultaneous spectrophotometric determination of aluminum and beryllium using mean centering of ratio spectra

A new micelle-mediated extraction method for preconcentration of ultra-trace quantities of beryllium and aluminum as a prior step to their simultaneous spectrophotometric determination has been developed. Chrome Azurol S (CAS), cetyltrimethylammonium bromide (CTAB) and Triton X-114 were used as chelating agent, cationic surfactant for extraction and co-extraction agent, respectively. Mean centering (MC) of ratio spectra has been used for simultaneous analysis of beryllium and aluminum. The optimal extraction and reaction conditions were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 5-40 ng mL⁻¹ of beryllium and 3-100 ng mL⁻¹ of aluminum. The detection limit of the method is 0.98 and 0.52 ng mL⁻¹ for beryllium and aluminum, respectively. The interference effect of some anions and cations was also tested. The method was applied to the simultaneous determination of beryllium in water samples.     

Determination of Aluminum and Beryllium by Diffuse Reflectance Spectrometry with the Use of Chromaticity Functions

Immobilized Eriochrome Cyanine R was used for the direct determination of trace aluminum and beryllium by diffuse reflectance spectrometry. Anion exchanger AV-17, silica gel Silochrom C-120, Chromaton N-Super, octadecyl silica gel, and cellulose were examined as supports. Optimal sorption conditions were found. The dependence of chromaticity functions (chromaticity coordinates, lightness, color saturation, yellowness, and whiteness) on different factors was studied. Advantages of the use of chromaticity functions rather then the diffuse reflectance coefficient were demonstrated. A method is developed for the separate determination of aluminum and beryllium using cellulose as the support; the method was used for the analysis of real samples and tested with standard samples. When solution samples of 50 and 100 mL were used, the determination limit was 0.004 g/mL for aluminum and 0.0002 g/mL for beryllium.     

Invers-Voltammetrische Bestimmung von Aluminiumspuren in Gegenwart von Beryllium

Abstract

An inverse voltametric method is described for determining traces of aluminum in beryllium and its compounds. The method is based on the electrochemical oxidation of the aluminum solochrome violett RS complex at a carbon paste electrode. The determination can be carried out in the ppm range without previous separation of other trace elements.     

The determination of aluminum by atomic absorption spectroscopy

A study of the determination of aluminum by atomic absorption spectroscopy has been made using a solution of aluminum cupferrate in 4-methyl-2-pentanone to feed oxy-acetylene or oxy-hydrogen flames. Investigations were made on the effect of the variables, viz., slit-width, flow rates, flow ratios and flame positions, on the intensity of aluminum absorption. The data were studied to determine the optimum conditions. These investigations brought out the comparative merits of the two flames for the determination of aluminum, and also elucidated the mechanism of aluminum absorption in an oxy-acetylene flame.     

Determination of beryllium in solid samples by flame atomic absorption spectrometry after preconcentration on activated carbon.

It is generally supposed that the preconcentration procedure is used for the determination of metal concentrations under the sensitivity of the measurement method. This study showed that preconcentration is also need for the beryllium (Be) concentration over the sensitivity of atomic absorption spectrometry. For this purpose, a simple and selective method for the determination of Be in solid samples is modified. The method is based on the preconcentration of the complexes of beryllium-acetylacetone plus morin, oxine, PAN and PAR on activated carbon at different pH values. The adsorbed beryllium was eluted with aqua regia and measured by flame atomic absorption spectrometry (FAAS). Recoveries of up to 85% were achieved. For removing chemical interferences and applying the method to Be determination in solid samples, the masking studies and reproducibility were examined. The detection limit was found to be 0.12 ng mL(-1). The relative sandard deviations (RSD) were found to be 8% for 60 mL of 10.0 ng mL(-1) using 10 replicate enrichment procedures. Beryllium concentrations in the studied solid samples were found in the range of 0.28 - 3.95 mg kg(-1).     

Flame atomic absorption spectrometric method for the determination of beryllium in natural waters after separation with N-benzoyl-N-phenylhydroxylamine

A procedure for the determination of beryllium in natural waters is proposed. A solvent extraction step was performed in order to overcome interferences and isolate beryllium before it was atomized by direct nebulization of the organic phase in a dinitrogen oxide-acetylene flame. N-Benzoyl-N-phenylhydroxylamine was used as the extractant whilst isobutyl methyl ketone was the organic solvent. The effects of pH, amine concentration in the organic phase, shaking time, stability of the complex and nature of the extracted species were studied. The detection limit and linear response range are 2 ng ml-1 and 0-1.0 microgram ml-1, respectively. The result obtained for a standard reference material compared well with the quoted value.     

A study of some matrix effects in the determination of beryllium by atomic-absorption spectroscopy in the nitrous oxide-acetylene flame

A study has been made of a number of interferences observed in the trace determination of beryllium by atomic-absorption in the nitrous oxide-acetylene flame. The major negative interference caused by the presence of excess of aluminium salts may be overcome by the use of 8-hydroxyquinoline. Magnesium and silicon also depress the Be signal, but most other metals cause enhancement. In most instances the enhancements may be made uniform by the addition of potassium ions to the sample solution.     

固相萃取-石墨炉原子吸收法光谱分析铝合金中痕量铍的研究

建立了固相萃取-石墨炉原子吸收光谱法测定铝合金中铍的方法。利用偶氮砷酸类试剂7-(2′-胂酸基-5′-羧酸)苯偶氮-8-羟基喹啉-5-磺酸(H2L)与Be2+形成螯合物,该螯合物可用C18固相萃取柱富集,而Al3+则不被保留。采用石墨炉原子吸收光谱法(GF-AAS)测定C18柱洗脱液中的Be2+的螯合物,从而实现铝合金中铍的分离检测。最佳实验条件为:采用pH=3.0的5%H2L水溶液螯合Be2+,水相上柱,用2mL体积比为50%的甲醇/水溶液作为洗脱液。结果表明:经过C18柱固相萃取可以去除Al3+的干扰,Be2+的测定范围为0.05～16μg/L,检出限为0.025μg/L,加标回收率为92%～108%。应用该法于铝合金标样中铍的测定,结果与认定值相符。     

Comparative study for aluminum determination in bone by atomic absorption techniques and inductively coupled plasma atomic emission spectroscopy

A comparative investigation was carried out on the suitability of atomic absorption spectrometry and inductively coupled plasma atomic emission spectroscopy for aluminum determination in bone. Both techniques give reliable results but the nitrous oxide-acetylene flame method was not found to be sensitive enough to accurately measure low aluminum content. A suitable method for sample treatment is also described. Quantitation of aluminum in bone from patients on regular hemodialysis is also done.     

Acid–Base Titration: Analysis of Phosphoric Acid Anodizing Solutions. A Problem-Based Learning Approach

Phosphoric acid anodizing solutions are routinely titrated to monitor their concentrations; however, after successive anodizations of aluminum metal, increasing amounts of dissolved aluminum interfere with the neutralization titration. The true concentration of phosphoric acid is determined by a correction factor based on the concentration of the dissolved aluminum, which is determined industrially by flame atomic absorption spectrometry. The academic determination of a correction factor for aluminum as well as copper can be designed as a traditional or a problem-based learning exercise.     

Test determination of aluminum, beryllium, and cationic surfactants using phenolcarboxylic acids of the triphenylmethane series immobilized on cloths from synthetic and natural fibers

We consider the use of cloth matrices from viscose and cotton fibers bearing phenolcarboxylic acids of the triphenylmethane series immobilized by adsorption in chemical test methods of analysis. Chrome Azurol S, Sulfochrome, and Eriochrome Cyanine R were used for immobilization. It was found that the reagents are weakly retained on cellulose matrices. The degree of retention varied from 10 to 60%. It was observed that the reagent complexes of metal ions exhibited enhanced adsorbability on the matrices. Cloths with immobilized Chrome Azurol S were used in the test determination of 0.0005–0.5 mg/L beryllium and 0.0005–1.0 mg/L aluminum. When the reaction products were preconcentrated on the cloth from 100 mL of a test solution, the detection limit was 0.0001 mg/L. Procedures were developed for determining 0.1–100 mg/L aluminum and 0.02–0.6 mg/L beryllium in solutions using cloth test strips encapsulated into a polymeric film. It was demonstrated that Sulfochrome and Eriochrome Cyanine R immobilized on cloths can be used to determine 0.01–1 and 1–1000 mg/L cationic surfactants.     

Interference of aluminum chloride and nitrate on alkaline earth elements in an air-acetylene flame

Aluminum nitrate causes a strong interference in the determination of alkaline earth elements in the air-acetylene flame by formation of mixed oxides, predominantly of the spinel-type M^IIAl₂O₄. The influence of aluminum chloride is less pronounced because the analyte chloride must be converted to the oxide before it reacts with aluminum oxide. Any compound that delays the formation of oxides hence alleviates the depressing effect of aluminum. Particle size plays a decisive role in the sensitive equilibrium between alkaline earth chloride and oxide formation. Aluminum chloride hexahydrate hydrolyzes on desolvation in the flame, giving off HCl. This way an atmosphere of HCl is generated inside larger particles that isolate the analyte from oxygen in the flame gases and favor formation of thermally less stable chlorides, and hence atomization. Addition of an excess of cesium chloride increases the average particle size further and supports that mechanism. Moreover, cesium chloride causes an early disintegration of large particles releasing analyte chlorides into the flame, thus enhancing their degree of atomization.     

A highly sensitive spectrophotometric determination of beryllium with chromal blue G and cetyltrimethylammonium chloride

Chromal blue G in the presence of cetyltrimethylammonium chloride is proposed for the spectrophotometric determination of microgram amounts of beryllium. The sensitivity of color reaction between beryllium and chromai blue G has been greatly increased by the sensitizing action of cetyltrimethylammonium chloride (_626nm = 93,000). Beer's law is obeyed over the range 0.012–0.12 ppm of beryllium. Full color development occurs in 20 min at pH 5.5 and at 626 nm. The mole ratio of beryllium and chromai blue G in the complex is estimated to be 1:2. The proposed method is very sensitive and selective for determination of beryllium when EDTA is used as a masking agent.     

Determination of beryllium in urine by graphite-furnace atomic absorption spectrometry

A method has been developed for the determination of beryllium in urine by graphite-furnace atomic absorption spectrometry. Ammonium 12-molybdophosphate and ascorbic acid were employed as a matrix modifier. The tolerable charring temperature for beryllium in both aqueous solution and urine was raised to 1400 °C in the presence of a matrix modifier. The sensitivity for the determination of beryllium was also improved by a factor of 1.5 in comparison with that obtained by using magnesium nitrate as a matrix modifier. The mechanism of the enhancement effect of ammonium molybdophosphate was ascribed to the effectiveness of the formation of gaseous BeO, which is a precursor of free beryllium. Beryllium in urine can be determined simply by dilution with ascorbic acid solution. The relative standard deviation for seven replicate determinations of beryllium was 1.9% for a urine sample containing 0.029 μg ml^?1 of beryllium.     

Determination of beryllium,barium, vanadium and some other elements in water by atomic absorption spectrometry with electrothermal atomization

The determination of beryllium, barium and vanadium by atomic absorption spectrometry in an uncoated graphite furnace poses several problems, e.g. bad reproducibility, memory effects, etc. These difficulties can be avoided by using tubes coated with pyrolytic graphite and carbide. The optimal temperature for the pyrolytic graphite coating and the quantity of lanthanum that should be introduced for the carbide coating are discussed. Beryllium, barium and vanadium in surface water and tap water can be determined without memory effects and with detection limits of 0.01, 1 and 1μg l^-1, respectively. Good agreement was found with the results obtained by activation analysis and flame or flameless (with uncoated tubes) atomic absorption spectrometry after preconcentration. The lifetime of the coated tubes was increased, and improved results were also found for the determination of other carbide-forming and/or high-melting elements such as molybdenum, cobalt, nickel, copper and chromium.     

Indirect atomic absorption determination of aluminum by flow injection analysis

An indirect atomic-absorption spectrometric method for the determination of aluminum carried out by flow injection analysis is proposed. This method is based on the enhancement of the atomic signal of iron, using a fuel-rich air-acetylene flame, by small amounts of aluminum, which allows the indirect determination of aluminum in the concentration range 0.2–1.8 μg ml⁻¹ (r.s.d. 1.2%). The sampling frequency is 150 hr⁻¹ for an injected volume of 54 μl. An extensive study of interferences has been compared, with considerable advantage, over the conventional method.     

Automated radioanalytical determination of lead and beryllium

The automated modification of the radioanalytical determination of lead and beryllium using AutoAnalyzer modules has been developed. The method for lead determination is based on a two-phase isotope exchange of lead between the sample solution labelled with²¹²Pb and the standard lead diethyldithiocarbamate solution in carbon tetrachloride. For the determination of beryllium a substoichiometric isotope dilution method using⁷Be as tracer and acetylacetone in chloroform as extractant was used. As little as 0.02 μg/ml of lead and 2 μg/ml of beryllium can be determined by the methods above. The flow diagrams of the automated procedures are presented.