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Analytical and Bioanalytical Chemistry (v.356, #8)
A new fast and fault-tolerant identification algorithm for spectral databases by R. Wallwitz; W. Baumann (pp. 463-470).
A new method for an automatic, computer and database driven identification of UV/VIS spectra is described. It is shown that an identification algorithm must consider the spectral differences as well as their common features. The described identification method allows identifications, even if the spectra are distorted or shifted.
Parametric analysis of the inductively coupled plasma by I. Holclajtner-Antunović; Z. Raspopović; V. Georgijević; M. Tripković; J. Georgijević (pp. 471-475).
A systematic parametric study of an LTE (local thermodynamic equilibrium) mathematical model of pure inductively coupled argon plasma (ICAP) used for spectrochemical purposes was performed by means of computer simulations. The spatial distributions of temperature, gas velocity, magnetic field and energy losses were investigated under typical plasma operating conditions as function of the ICAP geometrical dimensions and dynamic parameters. These theoretical calculations can be used to predict the properties of the applied plasma in the course of practical work, to choose the optimal conditions by changing the operating parameters and to interpret existing analytical results.
Electrochemical response of a carbon paste electrode containing an adsorbed species on incorporated alumina by Pedro Navarro; Claude Jambon; Olivier Vittori (pp. 476-479).
The electrochemical response of carbon paste electrode was investigated containing an inorganic and a non-electroactive compound on which an electro- active organic molecule was adsorbed. Alizarin S was chosen as the test molecule adsorbed on 150 m2/g of alumina, because this molecule is either easily reduced or oxidized on carbon. The electrode response was found to be linear for low amounts of alumina containing a known amount of Alizarin S. The electrical yield was never higher than 50%, but was reproducible. An increasing alumina amount in the paste increased the response, but lowered the electrical yield.
Selective method for the determination of gold by anodic stripping voltammetry by Mieczysław Korolczuk (pp. 480-483).
A highly selective method for the deter- mination of gold by anodic stripping voltammetry is described. For preconcentration a glassy carbon electrode, activated by deposition of small amounts of gold before the measurement, is proposed. The Au3+ reduction process at such an electrode is effective starting with the potential +0.4 V vs. Ag/AgCl electrode. A linear dependence of the current of the gold stripping peak on the gold concentration was obtained in the range from 5×10−8 to 1×10−6 mol/l. The relative standard deviation for 2×10-7 mol/l HAuCl4 was 4.2% (n=5). The detection limit was 4×10-9 mol/l. The accuracy of the method was verified by the determination of gold in reference materials.
Quantitative analysis of thin films of RBa2Cu3O7−x (R-rare earth elements) and ZrO2 (Y2O3) buffer layers by SNMS by J. A. Rebane; A. R. Kaul; Yu D. Tretyakov (pp. 484-487).
It is shown that RBa2Cu3O7-X single crystals may be used as reference samples for the quantitative analysis of RBa2Cu3O7-X thin films by SNMS. RSF-values for Y and Cu (relative to Ba) determined for ceramic RBa2Cu3O7-X samples are higher than those for single crystals. This difference may be caused by Ba segregation on grain boundaries. The depth profile analysis of YSZ/Al2O3 samples was performed by DBM using a Ni grid to prevent sample charging. The reproducibility of analysis was better than 10%.
A strategy for chromatographic and structural analysis of monosaccharide species from glycoproteins by M. H. Gey; K. K. Unger (pp. 488-494).
A general strategy for the chromatographic and structural analysis of the monosaccharide species fucose (Fuc), N-acetylgalactosamine (GalNAc), N-acetylglucosamine (GlcNAc), galactose (Gal), glucose (Glc), mannose (Man), N-acetylneuraminic acid (NANA) present in glycoproteins is described. Qualitative and quantitative aspects for the separation of these glycoprotein monosaccharides (monosaccharide species) using ligand-exchange chromatography (LEC) and high pH anion-exchange chromatography (HPAEC) in combination with pulsed-amperometric detection (PAD), refractive index (RI) and ultraviolet (UV) monitoring are discussed in detail. The conditions for the acidic hydrolysis of glycoproteins and for the liquid chromatographic analyses of glycoprotein monosaccharides using HPAEC and LEC technique were optimised. Furthermore, the characterisation of glycoproteins according to their purity and molecular mass connected with a comparison to biomolecules that are not glycosylated or whose extent of glycosylation is low was carried out by means of matrix-assisted laser-desorption ionisation mass spectrometry (MALDI-MS). The identification of glycoprotein monosaccharides using an on-line coupling liquid chromatography mass spectrometry (LC-MS/MS) was performed by means of their characteristic “quasi molecule ions” such as (M + NH4)+ and (2M + NH4)+. The different chromatographic and structural methods used in combination with each other were applied to characterise and determine the monosaccharide species of fetuin and a membrane glycoprotein fraction.
High-performance liquid chromatography – atmospheric pressure negative chemical ionisation – mass spectrometry of 2,4-dinitrophenyl derivatives of amines by U. Fuchslueger; K. Rissler; H. -J. Grether; M. Grasserbauer (pp. 495-499).
High-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) is used to detect 2,4-dinitrophenyl (DNP) derivatives of amines by means of negative chemical ionisation at atmospheric pressure. The high sensitivity and good comparability of UV- and MS-detection of DNP-derivatives of amines is shown by several examples. The high selectivity of the derivatisation and the detection method (UV and MS) is used for the analysis of unknown amines in aqueous phases after hydrolytic degradation of polyamide-amine- or polyamine-epoxide-adducts as well as for the characterisation of commercial products.
Adsorptive stripping voltammetric analysis of 2,4,6-tri(2′pyridyl)-1,3,5-triazine at a mercury electrode by M. M. Kamal; Ali Z. Abu Zuhri; Amna A. O. Nasser (pp. 500-503).
The redox behaviour of adsorbed species of 2,4,6-tri(2′-pyridyl)-1,3-5-triazine (TPTZ) at the surface of a mercury electrode was examined using cycling voltammetry. Based on the adsorption and accumulation of TPTZ at the charged mercury surface cathodic adsorptive stripping voltammetry (CSV) is applied for the trace determination of TPTZ using a differential pulse (DP) technique. Experimental and operational parameters for the quantitative analysis of TPTZ are optimized and the detection limit was found to be 3×10−9 mol/l. The effect of some interferences, e.g. organic compounds, cations and anions, are investigated.
Determination of α-amylase activity using Fourier transform infrared spectroscopy by P. Krieg; B. Lendl; R. Vonach; R. Kellner (pp. 504-507).
A new method for the determination of α-amylase activity in aqueous solutions and human serum with FTIR-spectroscopy is proposed. The chemical reaction catalyzed by the enzyme under study can be followed directly when applying FTIR-spectroscopic detection also in the case, where no colored or electrochemical active species are generated or consumed during the course of the reaction of α-amylase with simple starch. Therefore the determination of the α-amylase activity could successfully be performed by recording two FTIR-spectra, one immediately after mixing the sample and a substrate (starch-) solution and the other after a 20 min reaction time. From these two FTIR-spectra a difference spectrum was calculated hereby eliminating an unspecific absorption of the matrix. The intensities of the resulting difference spectra corresponded to the extent of the reaction which took place during the investigated time interval and hence could be related to the activity of the enzyme in the sample. The developed method is linear from 80 to 1400 U/l (r.s.d.=5% for 700 U/l) in aqueous solutions and was also successfully applied to the determination of α-amylase activity in human serum where a linear working range from 100 to 800 U/l (r.s.d.=11% for 150 U/l) was achieved.
Multiresidue determination of sulfonylurea herbicides by capillary electrophoresis for hydrolysis studies in water and sediments by B. M. Berger; N. Lee Wolfe (pp. 508-511).
Twelve sulfonylurea herbicides (bensulfuron-methyl, sulfometuron-methyl, ethametsulfuron-methyl, triasulfuron, tribenuron-methyl, nicosulfuron, chlorimuron-ethyl, thifensulfuron-methyl, primisulfuron-methyl, metsulfuron-methyl, chlorsulfuron, and amidosulfuron) were separated by free zone capillary electrophoresis with migration times less than 20 min. The additional simultaneous determination of the 2,3-dihydro-3-oxobenzisosulfonazole (saccharin) degradation product was possible after application of a temperature and voltage gradient. Detector responses (absorbances) at 239 and 220 nm were linear between 0.1 and 10.0 μg/ml. After extraction with acetonitrile, recoveries for the same concentration range from two different sediments were higher than 90% with variation coefficients lower than 16%. Dissociation constants of the sulfonylurea herbicides were determined.
Total digestion of silicate containing matrices (plants, soil, sludges) using a pressure ashing device with PFA-vessels by P. Schramel; I. Wendler; G. Knapp (pp. 512-514).
A digestion procedure for silicate containing matrices like soil, sludge, etc. by using a commercially available pressure ashing device (Seif-Aufschluβtechnik, Germany) with PFA (perfluoroalkoxy) sample vessels is described at the results for different matrix- and trace elements in different suitable certified standard reference materials. The advantages of this technique compared with the use of Teflon®-(PTFE, polytetrafluoroethylene) vessels and the open treatment in Pt-crucibles will be discussed.