Beryllium Acetylacetonate Research Articles

Validation of a standardised method for determining beryllium in human urine at nanogram level

The potential toxicity of beryllium at low levels of exposure means that a biological and/or air monitoring strategy may be required to monitor the exposure of subjects. The main objective of the work presented in this manuscript was to develop and validate a sensitive and reproducible method for determining levels of beryllium in human urine and to establish reference values in workers and in non-occupationally exposed people. A chelate of beryllium acetylacetonate formed from beryllium(II) in human urine was pre-concentrated on a SPE C18 cartridge and eluted with methanol. After drying the eluate, the residue was solubilised in nitric acid and analysed by atomic absorption spectrometry and/or inductively coupled plasma mass spectrometry. The proposed method is 4 to 100 times more sensitive than other methods currently in routine use. The new method was validated with the concordance correlation coefficient test for beryllium concentrations ranging from 10 to 100 ng/L. Creatinine concentration, urine pH, interfering compounds and freeze-thaw cycles were found to have only slight effects on the performance of the method (less than 6%). The effectiveness of the two analytical techniques was compared statistically with each other and to direct analysis techniques. Even with a detection limit of 0.6 ng/L (obtained with inductively coupled plasma mass spectrometry), the method is not sensitive enough to detect levels in non-occupationally exposed persons. The method performance does however appear to be suitable for monitoring worker exposure in some industrial settings and it could therefore be of use in biological monitoring strategies.

Quantum-chemical studies of the protonation of beryllium β’diketonates

Possible routes of the protonation of the free beryllium malonate Be(Mal)2 and beryllium acetylacetonate Be(Acac)2 complexes were determined by the quantum-chemical method in the DFT approximation. The influence of the protonation on the electronic and molecular structures (geometry of the metallocycles, energies and compositions of the molecular orbitals, effective charges on the atoms, and site occupancies of atomic orbital overlapping) was studied. The change in the energy of the molecular orbitals was considered as a function of their localization on the protonated and nonprotonated ligands of the complexes. The addition of a proton to one of the oxygen atoms was shown to be most probable.

Structure and vibrational assignment of beryllium acetylacetonate

The structure of beryllium acetylacetonate, Be(acac)2, was fully optimized at the B3LYP (using the 6-31G*, 6-311G*, and 6-311++G(3df,2p) basis sets), Hartree–Fock, and the Möller–Plesset (using the 6-31G* basis set) levels. The frequency and intensity of the vibrational bands of Be(acac)2 and its 1,3,5-13C; 2,4-13C; 3-2H; 3-2H–2,4-18O derivatives were obtained at the B3LYP level using 6-311G* basis set. We also calculated the anharmonic frequencies at the B3LYP/6-311G* level of theory for Be(acac). The calculated frequencies are compared with the experimental Fourier transform IR and Raman spectra. All of the measured IR and Raman bands were interpreted in terms of the calculated vibrational modes. The scaled theoretical frequencies and the structural parameters are in excellent agreement with the experimental data. Analysis of the vibrational spectra indicates a strong coupling between the chelated ring modes. Four bands at the 1042, 826, 748, and 480cm−1 are found to be mainly due to the metal–oxygen stretching motions.

Low-temperature volatilization of Be acetylacetonate for sample introduction in ETV-ICP-AES

A new method for determination of trace beryllium by electrothermal vaporization (ETV)-inductively coupled plasma atomic emission spectrometry (ICP-AES) with the use of acetylacetone as chemical modifier is developed. Trace beryllium was vaporized as acetylacetonate into plasma at a low-temperature of 700°C, and the vaporization behavior of acetylacetonate of beryllium was investigated in detail. Under the optimized conditions, beryllium acetylacetonate could be quantitatively vaporized. The detection limit of beryllium was 0.2 ng ml −1, compared with the conventional pneumatic nebulization ICP-AES, the detection limit could be improved by 45-fold. The relative standard deviations for 0.01 μg ml −1 of Be was 4.1%. The linear range of the calibration curve covered three orders of magnitude. The proposed method was applied to the determination of trace beryllium in human hair standard reference material and the results obtained were in good agreement with the reference values.

Determination of Trace Amounts of Beryllium(II) in Drinking Water and of Beryllium Vapor in Air by Graphite-Furnace Atomic Absorption Spectrophotometry Using Acetylacetone as a Chelating Agent

A chelate of beryllium acetylacetonate, Be(acac)2, was formed from beryllium(II) (1.0 - 40.0 ng) in drinking water (100 ml) containing acetylacetone (0.2%(v/v), 7.0 - 14.0 ml) in ammonium acetate buffer (14 - 28 mmol) together with a slightly acidic solution (0.2%(v/v) of HCl, 3.0 ml) at pH 5.5. The Be(acac)2 chelate was preconcentrated on a Sep-Pak C18 cartridge and was eluted with methanol (2.00 ml). A portion (20 µl) was introduced into a graphite cuvette and was atomized according to a temperature program. The method detection limit (3σ) for beryllium(II) was 2.3 ng/l; the calibration graph was linear up to 400 ng/l. Accuracies of 97.0 - 101% were obtained when testing a quality control (QC) water sample (HPS #290608) and a synthetic natural water standard (Standard Reference Material 1643d) with a relative standard deviation (n=4) within 2.3%. The proposed method could be applied to the measurement of beryllium vapor in air with a detection limit of 0.23 ng.

A spirobicyclic complex of Schmidpeter's ligand, bis(tetraphenylimidodiphosphinato)beryllium, Be(OPh2PNPPh2O)2, an inorganic analog of beryllium bis(?-diketonates)

The crystal structure of bis(tetra-phenylimidodiphosphinato)beryllium (as a benzene solvate), Be(OPh2PNPPh2O)2. C6H6, was determined by X-ray diffraction and compared with that of beryllium acetylacetonate, Be(OCMeCHCMeO)2. The imidodiphosphinate is an inorganic spirobicyclic system, Be(OPNPO)2, with tetrahedrally coordinated beryllium. Unlike the planar BeO2C3 rings in the acetylacetonate, the two six-membered BeO2P2N inorganic rings are nonplanar and display a skew boat conformation. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:244–248, 2000

Determination of Trace Beryllium in Natural Waters by Gas Chromatography-Helium Microwave Induced Plasma Emission Spectrometry

The determination of Be in natural water by gas chromatography-helium microwave induced plasma emission spectrometry is described. Beryllium was concentrated about 230 times by the extraction with acetylacetone into chloroform and by further evaporation of the solvent. A batchwise ligand vapor method was used to prevent any beryllium acetylacetonate from remaining in the gas chromatographic column. The detection limit was 10pg in 30ml of water sample and the relative standard deviation was 4.1% at 10ng of Be. The method was applied to the determination of Be in lake water samples.

Determination of boron in aluminum and aluminum-magnesium alloy by charged particle activation analysis

Charge particle activation analysis is applied to the determination of boron in aluminum and aluminum-magnesium alloy. The /sup 10/B(p,..cap alpha..)/sup 7/Be, the /sup 10/B(d,..cap alpha..n)/sup 7/Be, and the /sup 10/B(d,n)/sup 11/C reactions are used. Proton activation allows an instrumental determination. When the /sup 10/B(d,..cap alpha..n)/sup 7/Be reaction is used, beryllium-7 is separated from the matrix by liquid-liquid extraction; beryllium acetylacetonate is extracted with carbon tetrachloride after complexation of other metal ions with ethylenediaminetetraacetic acid. After back extraction beryllium is precipitated as beryllium hydroxide and heated to beryllium oxide. When the /sup 10/B(d,n)/sup 11/C reaction is used, carbon-11 is separated as carbon dioxide by dissolution of the sample in a mixture of sulfuric acid, phosphoric acid, water, and potassium dichromate. The chemical yield of both separation methods was determined. The results obtained have a relative standard deviation of 5-9% at the 1-33 ..mu..g/g concentration. The different nuclear reactions yield results that are in good mutual agreement and also agree satisfactorily with those of nonnuclear analytical methods.

Atomic-absorption determination of beryllium in geological materials by use of electrothermal atomization

A method is described for the atomic-absorption determination of beryllium in geological materials, that utilizes electrothermal atomization after a separation by solvent extraction. Samples are decomposed with hydrofluoric acid and nitric acid in Teflon-lined pressure decomposition vessels. Beryllium is isolated by its extraction as beryllium acetylacetonate at pH 8 into xylene and back-extraction in 3 M hydrochloric acid. The method has been successfully applied to the determination of beryllium in 14 U.S. Geological Survey standard rocks. Four subsamples from four bottles of each standard sample were analysed in random order. The mean beryllium contents (ppm) are: AGV-1, 1.98; PCC-1, 0.024; MAG-1, 2.84; BHVO-1, 0.90; DTS-1, 0.026; SCo-1, 1.74; SDC-1, 2.52; BCR-1, 1.44; GSP-1, 1.22; SGR-1, 0.86; QLO-1, 1.83; RGM-1, 2.21; STM-1, 8.75; G-2, 2.29. An analysis of variance shows that all the samples may be considered homogeneous at F 0.95 except AGV-1 and DTS-1 which may be considered homogeneous at F 0.99.

Determination of the formation quotients of Be-EDTA complexes by solvent extraction

The formation quotient of the Be-EDTA complex, BeY 2−, was determined using ligand competition in a solvent extraction system. The distribution quotients of beryllium acetylacetonate were measured by means of γ counting of 7Be in a system CCl 4H 2O at a constant ionic strength of 0·1 M NaNO 3 at 30°C. The result obtained: log β 4 = 8·68±0·02 where β 4 = [ BeY 2−] [ Be 2+][ Y 4−] , agrees with results listed in the literature.

Separation and purification of beryllium by the fractional sublimation of beryllium acetylacetonate

Solutions containing beryllium(II) in admixture with most common metals can be treated with acetylacetone to form the beryllium and various other acetyl-acetonates which precipitate. The precipitate is filtered, washed, dried and fractionally sublimed in a special sublimator. After sublimation with air as a carrier gas the beryllium acetylacetonate fraction is recoverable in high purity. Zinc is the only detectable contaminant by atomic absorption spectrometry but can be eliminated by masking with ammonium thiocyanate before the formation of the metal acetylacetonates. Beryllium fractions were checked for purity by atomic absorption spectrometry and found to contain less than 0.002% Zn after a single sublimation. The method appears to offer an excellent method of purification for beryllium if quantitative recoveries are not required.

Metal coordination polymers. I. Synthesis and thermogravimetric analysis of beryllium phosphinate polymers

AbstractThe preparation, properties, infrared, DTA, and TGA data are given for beryllium dimethyl‐, tetramethylene‐, di‐n‐butyl‐, di‐n‐pentyl‐, di‐n‐heptyl‐, methylphenyl‐, diphenyl‐, and bispentafluorophenylphosphinates. Synthesis of dimeric beryllium acetylacetonyl phenyl‐[o‐methylcarboranyl (B10)] phosphinate is reported. The beryllium phosphinates were prepared by the reaction of beryllium acetylacetonate with the appropriate phosphinic acid.

Limits of Detection of Beryllium in Tissues by Microemission Spectrography

Abstract The metal beryllium has been successfully and unequivocally demonstrated by microemission spectrography on a semiquantitative basis in tissue sections 50 microns thick. The beryllium was localized in individual pulmonary granulomas in dogs exposed to beryllium. The determination of the lower limit of detection could indicate the threshold level of beryllium in tissue that can induce injury. Beryllium acetylacetonate dissolved in technical-grade xylene was used to prepare a series of working standards. Initial results indicate that as little as 1.48 × 10−12 gm of beryllium is a sample of paraffin weighing about 2.91 × 108 gm has been detected. Similar or greater quantities of beryllium have been demonstrated in similar-size samples of embedded lung tissue from dogs exposed to beryllium.

Radiochemical procedure for beryllium

A radiochemical procedure is given for the determination of beryllium activity in the presence of mixed fission products and uranium. Decontamination is achieved by adsorption of contaminants on anion-exchange resin from HCl solution, by ferric hydroxide scavenging, and by extraction of beryllium acetylacetonate from a weakly acidic EDTA solution. Two cycles of the procedure have results in a decontamination factor of 3 × 10 8 and a chemical yield of 90 per cent.

209. The dipole moments of benzoquinone, beryllium acetylacetonate, basic beryllium acetate, and o-nitrophenol

209. The dipole moments of benzoquinone, beryllium acetylacetonate, basic beryllium acetate, and o-nitrophenol

Polarisation measurements on basic beryllium acetate and beryllium acetylacetonate

An investigation of organic beryllium compounds is being carried out by one of us (W. R. A.) with a view to obtaining information regarding their molecular configuration and a study of their molecular polarisations suggested itself as a means of deciding whether or not these compounds are spatially symmetrical. No previous attempts appear to have been made to measure the dipole moment of compounds of this type; other physical measurements have been made and will be discussed in a later section. In the present investiga­tion measurements have been made in benzene and carbon tetrachloride solution, but in both solvents the compounds are only sparingly soluble. 2. Purification of Materials . Beryllium Compounds .—Small quantities of basic beryllium acetate and beryllium acetylacetonate were very kindly supplied by Professor G. T. Morgan, F. R. S., and Dr. S. Sugden, and our best thanks are due to them. The melting points of the compounds were in accord with the values quoted at the literature: acetate, m.p. 285° C.; acetylacetonate, m.p. 108-5° C. Micro-chemical analyses, carried out by Dr. Schoeller, in Berlin, gave the following table.

The diamagnetic susceptibilities of some beryllium compounds

The investigation of the molecular structure of organic beryllium compounds is being studied by one of us (W. R. A.) from the standpoint of their infra-red absorption spectra. During a mechanical defect in the infra-red apparatus the diamagnetic susceptibilities of basic beryllium acetate, propionate, and pivalate, and of beryllium acetylacetonate were measured in order to obtain further physical data on the structure of these molecules. The susceptibilities were measured on a Curie-Chéneveau magnetic torsion balance by the method previously described by Farquharson. Measurements were made at 18° C. The compounds were finely powdered in an agate mortar and packed tightly into a small graduated glass tube of very slight susceptibility. Packing of solids is most important in diamagnetic susceptibility measurements. In­ efficient packing leads to values of the specific susceptibility much lower than the true value. This diminution results from the fact that the volume of solid is virtually diminished by air spaces and a volume correction should be applied.