A new concept for the quasi non-destructive microsampling of historical glasses

A mobile and easily practicable microsampling technique for historical glasses and its application is presented. About 100 μg of material is scraped off the object with a fine grinding file. The analysis of main, minor and trace elements in the digested sample is performed by IC, GFAAS and FIA with photometric detection. The procedure has been verified by measurements of standard glasses. Investigations of baroque ruby glasses showed the suitability of the microsampling technique for archaeometrical application. Received: 6 January 1997 / Revised: 17 March 1997 / Accepted: 25 March 1997     

Ammonium nitrate-polymer glasses: a new concept for phase and thermal stabilization of ammonium nitrate

Dissolving of ammonium nitrate in highly polar polymers such as poly(vinylpyrrolidone) and/or poly(acrylamide) can result in the formation of single-phase glassy solid materials, in which NH 4 (+) and NO 3 (-) are separated through an ion-dipole interaction with the polymer matrix. Below the glass transition temperature of the polymer matrix the resulting materials remain phase and thermally stable as demonstrated through the absence of decomposition as well as the solid-solid transitions and melting of ammonium nitrate. The structure of the materials is explored by Fourier transform infrared spectroscopy and density functional calculations. Differential scanning calorimetry, thermogravimetry, and isoconversional kinetic analysis are applied to characterize the thermal behavior of the materials.     

Perforated dried blood spot accurate microsampling: the concept and its applications in toxicokinetic sample collection

Dried blood spot (DBS) sampling has gained considerable interest as a microsampling technique to support drug discovery and development owing to its enormous ethical and practical benefits. Quantitative determinations of drugs and/or their metabolites collected in DBS matrix in its current format, however, have encountered technical challenges and regulatory uncertainty. The challenges of DBS bioanalysis are largely ascribed to the way how samples are collected and analyzed. Currently, an uncontrolled amount of a blood sample, e.g. 20 µl, is collected per time point per sample and spotted onto cellulose paper. Quantitation is based on removal of a fixed area of the DBS sample, resulting in sample waste, a need for mechanical punching and concomitant potential punching carryover, uncertainty in recovery assessment and the adverse impact of hematocrit on accurate quantitation. Here, we describe the concept and applications of a novel concept, namely perforated dried blood spot (PDBS), for accurate microsampling that addresses previous challenges. Advantages of PDBS are enumerated and compared with conventional DBS in the context of microsampling and liquid chromatography tandem mass spectrometry bioanalysis. Two approaches for accurate microsampling of a small volume of blood (5 µl) are proposed and demonstrated, i.e. Microsafe® pipettes and the Drummond incremental pipette. Two online sample enrichment techniques to enhance liquid chromatography tandem mass spectrometry sensitivity for microsampling bioanalysis are discussed. The PDBS concept was successfully applied for accurate sample collection (5 µl) in a toxicokinetic study in rats given a single oral gavage dose of acetaminophen. Perspectives on bioanalytical method validation for regulated DBS/PDBS microsampling are also presented. Copyright © 2012 John Wiley & Sons, Ltd.     

A new data management concept for AES and SAM

The problem of interchangeability of surface analytical data is gaining increasing importance in multi-method surface analysis. There are various surface analytical instruments in different laboratories on several automation levels. For these instruments, which are controlled by computer systems working with company-specific software under various operating systems, a standardised data format is necessary to allow an exchange of data. Therefore, we are developing a software package for the transfer, archiving and editing of surface analytical data called MAXMIND (management and exchange of method independent data), which is based on public domain software products. It allows the storage of all available and necessary information on experimental conditions and all parameters specific for a number of analytical techniques such as AES, SAM, XPS, SIMS, STM and AFM. Additionally, all data concerning the sample-preparation and the state of the instrument are included in order to allow a well-founded evaluation of the data and improved reproducibility of the experiment. This concept is demonstrated in detail for the two Auger techniques AES (Auger Electron Spectroscopy) and SAM (Scanning Auger Microscopy).Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

A new two-chip concept for continuous measurements on PMMA-microchips

A new concept for continuous measurements on microchips is presented. A PMMA (polymethylmethacrylate) based capillary electrophoresis chip with integrated conductivity detection is combined with a second chip, which undertakes the task of fluid handling and electrical connections. The combination of electrokinetic and hydrodynamic flows allows long-term continuous stable analyses with good reproducibilities of migration time and peak heights of analytes. The two-chip system is characterized in terms of stability and reproducibility of separation and detection of small ions. Relative standard deviations of <1% and 3% respectively for retention times and peak heights during long-term measurements can be achieved. The new system combines simple handling and automated analysis without the need for refilling, cleaning or removal of the separation chip after one or several measurements.     

A new concept in friction testing

Methods of measuring friction are reviewed and their shortcomings discussed. The advantages of using the wide range of test speeds, environmental conditions and recording facilities available on a tensile test machine are indicated and a new apparatus designed to fit a tensile tester is described. The design concepts are outlined in some detail and the factors limiting stick-slip motion are indicated. The apparatus can be used either for studies of materials or as an aid to product selection. Test results on a polyurethane rubber, covering a range of velocities and temperatures, illustrate the former, and tests on windscreen wiper blades under both wet and dry conditions illustrate the latter. Although primarily designed for testing the friction of polymers the apparatus is of universal application and can be used for measuring, against a chosen substrate, the coefficients of friction of metals, fabrics, paper, glass, leather, or any other material capable of being mounted in a vertical plane. It is not suitable for particulate matter such as sand, but could be used, for example, for studying the effect of floor finishes on a range of flooring materials.     

A new approach to non-destructive analysis of biofilms by confocal Raman microscopy

Confocal Raman microscopy (CRM) of biofilms enables one to determine the distribution of different microorganisms and other substances inside physiological intact microbial communities. These biofilms are of outstanding interest for biological wastewater treatment. In contrast to invasive techniques, such as fluorescent in situ hybridization (FISH), we were able to identify anaerobically ammonium-oxidising (anammox) bacteria without pretreatment processes of the samples just by its Raman vibrational signature. The presented results provide new insights into the complex interactions of different organisms in microbial communities without interfering with them.     

A new concept for sequencing DNA by capillary electrophoresis.

It is proposed that the scaling symmetry of constant charge density with increasing molecular weight, which prevents the separation by electrophoresis of DNA molecules in solution (with respect to molecular weight) be broken by the attachment of a perturbing entity (protein, virus or charged sphere) to one end of the molecule. An application of this idea to a concept for sequencing DNA by capillary electrophoresis is discussed, and the possibility of using the reattachment of the RecA protein to separate large segments of DNA in solution by electrophoresis following sequence-specific cleavage is mentioned.     

A new concept for the application of linear free energy relationships in catalysis

Linear free energy relationships (LFERs) have been used in heterogeneous catalysis for a long time. Their application to heterogeneous catalytic systems have been based on the original substituent concept introduced by Hammett [K.J. Laidler, Chemical Kinetics, Harper Collins Publishers, New York, 1987, pp. 246–251.]. This work deals with the idea of validating a new concept for the application of LFER in heterogeneous catalysis. Following this idea, the considered reactions center is the active site on the catalyst surface, rather than that of the reacting molecule. The confirmation of a successful application to HDS and hydrogenation reaction will be shown as a preliminary example of the potential of the new approach. The implications for catalyst design will be discussed.     

A new correlation between the characteristics temperature and glass-forming ability for bulk metallic glasses

Journal of Thermal Analysis and Calorimetry - A new criterion or parameter χ given by $$\left( {\frac{{T_{\text{x}} - T_{\text{g}} }}{{T_{\text{l}} - T_{\text{x}} }}} \right) \times \left(...     

A new concept for stress relaxation measurements of rubbers in compression

Current relaxation measurements and associated equipment are not reliable enough to carry out prolonged tests, especially at high temperatures and in liquid environments; the difficulties encountered in such measurements are discussed. The objectives of the present sponsored programme were to examine the best available equipment and experimental techniques and to develop a reliable and reproducible method for measuring stress relaxation in compression which could form a basis for a standard test procedure. In the course of this work, a method of evaluating the available equipment was developed and this is described.     

A new concept for coal water mixture stabilization using a polyelectrolyte

The stabilization mechanism of Sodium Polystyrene Sulphonate (PSSNa) on coal water mixture (CWM) has been examined using the following colloid chemical concept. It is realized that the stabilization of the CWM is due to an increase in electrostatic repulsion between the coal particles and the electrostatic repulsion is influenced strongly by the concentration of metal cations, especially Ca²⁺ eluted from the coal surface. The adsorption isotherm of PSSNa on the coal surface indicates a weak affinity type and the desorption amount of PSSNa is tremendously small in compared with the amount of adsorption. This indicates that a lot of PSSNa adsorbed weakly has been eliminated from the surface in the pre-washing process of desorption experiment. Furthermore, it appears that the -potential determined by the Acoustosizer for concentrated coal suspension shows higher values than the values determined by the usual electrophoresis, and that the high values hold for a wide range of salt concentrations in the medium. All these results indicate that much PSSNa is adsorbed weakly on the coal surface and the component plays a role in the stability character of CWM, where a large contribution of depletion stabilization effect can be expected.     

Substoichiometric and non-destructive determination of trace impurities in high-purity optical glasses by neutron activation analysis

A method of radioactivation analysis has been developed for the determination of 17 elements as impurities in high-purity optical glasses. The substoichiometric extraction of platinum with dithizone was studied and a simple procedure was proposed for the determination of platinum. Copper and manganese were also determined substoichiometrically by the extractions with dithizone and with thenoyltrifluoracetone, respectively. The non-destructive γ-ray spectrometry using a Ge(Li) detector has been applied for the determination of the other 14 elements (Ag, Co, Cr, Eu, Fe, Ir, Sc, Zn, Cs, Hf, Rb, Sb, Ta and Tb). Impurity elements at the ppb level were analysed by the proposed method and it is shown that the method is reliable for the determination of trace impurities in high-purity optical glasses.     

A novel algorithm for solving quasi penta-diagonal linear systems

In this paper, a novel numerical algorithm for solving quasi penta-diagonal linear systems is presented. The computational costs of the algorithm is less than those of three successful algorithms given by El-Mikkawy and Rahmo (Comput Math Appl 59:1386–1396, 2010), by Lv and Le (Appl Math Comput 204:707–712, 2008), and by Jia et al. (Int J Comput Math 89:851–860, 2012). In addition, a new recursive method for inverting the quasi penta-diagonal matrices is also discussed. The implementation of the algorithm using Computer Algebra Systems (CASs) such as MATLAB and MAPLE is straightforward. Two numerical examples are given in order to demonstrate the performance and efficiency of our algorithm.     

A new concept for corrosion inhibition of magnesium: Suppression of iron re-deposition

In our recent work (Höche et al. 2016) we proposed that non-faradaic dissolution of Fe impurities and/or iron containing phases with subsequent re-deposition of thin film of pure (“in statu nascendi”) iron enlarges cathodically active sites at the surface of corroding magnesium. The effect drastically accelerates corrosion of impurity containing Mg. In the present work we assume that if Fe re-deposition is prevented, the area of cathodic sites can be drastically decreased and hence corrosion of Mg can be suppressed. In this proof of concept work we use strong Fe^3 + complexing agents in order to remove dissolved iron cations from corrosion sites and prevent iron re-deposition. All used iron complexing agents efficiently lowered the corrosion rate of Mg. Direct correlation of complex stability with its inhibiting efficiency was established. It was shown that cyanide, salicylate, oxalate, methylsalicylate and thiocyanate efficiently reduce hydrogen evolution and suppress critical dark area formation.     

A modified ring electrographic method for the non-destructive analysis of metallic artefacts

Summary The utility of the ring electrographic technique as a non-destructive method of analysis of metallic artefacts of archeological importance is sufficiently accurate to give archeological meaningful results The electrographic sampling technique has been modified to give easier and more reliable sampling. The method is of particular value in the analysis of copper and silver coins.

---

Eine modifizierte elektrograpbische Ring-Methode zur Analyse metallischer Kunstgegenstände ohne deren Verletzung

Zusammenfassung Die Verwendbarkeit der elektrographischen Ring-Technik für die Analyse metallischer Gegenstände von archäologischem Interesse wurde erwiesen. Die elektrographische Probenahme wurde modifiziert. Das Verfahren ist für die Analyse von Kupfer- und Silbermünzen von besonderem Wert.

---

---

Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry

A new interface for the on-line coupling of a liquid chromatograph to a stable isotope ratio mass spectrometer has been developed and tested. The interface is usable for (13)C/(12)C determination of organic compounds, allowing measurement of small changes in (13)C abundance in individual analyte species. All of the carbon in each analyte is quantitatively converted into CO(2) while the analyte is still dissolved in the aqueous liquid phase. This is accomplished by an oxidizing agent such as ammonium peroxodisulfate. The CO(2) is separated from the liquid phase and transferred to the mass spectrometer. It is shown that the whole integrated process does not introduce isotope fractionation. The measured carbon isotope ratios are accurate and reproducible. The sensitivity of the complete system allows isotope ratio determination down to 400 ng of compound on-column. By-passing the high-performance liquid chromatography (HPLC) separation allows bulk isotopic analysis with substantially lower sample amounts than those required by conventional elemental analyzers. The results of the first applications to amino acids, carbohydrates, and drugs, eluted from various types of HPLC columns, are presented. The wide range of chromatographic methods enables the analysis of compounds never before amenable to isotope ratio mass spectrometry techniques and may lead to the development of many new assays.     

A new concept for the bioeffects-related analysis of xenoestrogens: Hyphenation of receptor assays with LC-MS

The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an enzyme-linked receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of receptor-ligand complexes by LC-MSMS. Received: 30 October 1998 / Revised: 18 December 1998 / Accepted: 26 December 1998     

A new concept for the bioeffects-related analysis of xenoestrogens: Hyphenation of receptor assays with LC-MS

The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an enzyme-linked receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of receptor-ligand complexes by LC-MSMS. Received: 30 October 1998 / Revised: 18 December 1998 / Accepted: 26 December 1998