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1.
A new concept based on hyphenation of biotests, for biological selection, and chemical analysis is introduced for water analysis. Biomolecular recognition components such as receptors, enzymes, and nucleic acids integrated in biological reaction chains are used for binding and selective enrichment of known and unknown biologically active substances in water samples; this is followed by identification and quantitation. The coupling of biomolecular recognition and binding to chemical analysis can be achieved either in discrete analytical steps, e.g. binding and elution of bioactive ligands from affinity columns followed by chemical analysis, or by methods capable of monitoring the binding of the ligand and simultaneous verification of its identity. This analytical strategy, denoted bioresponse-linked instrumental analysis (BLIA), enables detection of potential biological effects and identification of the analyte causing these effects. Several examples are presented.  相似文献   

2.
Different approaches to proximate analysis by thermogravimetry analysis   总被引:1,自引:0,他引:1  
The experimental optimization by the simplex method of the proximate analysis of coal and biomass by thermogravimetry analysis (TGA) is reported. Heating rate, final temperature, holding time, Ar flow rate and sample size were the control variables. The response function used was chosen to minimize the difference in percentage of volatile matter with the ASTM characterization. The relative accuracy of the method was demonstrated by determination of the volatile matter contents of a number of coals in parallel with the ASTM certified method. The method is successfully used with biomass samples.  相似文献   

3.
Summary A reliable and robust automated device for simultaneous voltammetric analysis (by differential pulse anodic stripping voltammetry) of several of the most toxic trace metals (Cu, Pb, Cd, Zn) in drinking and ground water is described. It enables in water works the required round the clock on line-monitoring of drinking water over extended periods (one week or longer) without supervision by staff. The device consists of adapted commercial polarographic instrumentation, a punch card program controller and automatic sampling and standard addition facilities. Extended tests under realistic routine working conditions in water works over several months have established the suitability and the potentialities of the concept and the satisfactory performance of the device.Ref. [4], [10] and [11] referring to automated flameless AAS methods for the study of biological materials constitute part I–III of this series  相似文献   

4.
A method is described to analyze observed conformations for molecular fragments with more than three torsional degrees of freedom. The method is an adaption of statistical cluster analysis to multidimensional, symmetric, periodic distributions of data points. Application to the molecular fragment M(PPh3)2 with eight torsional degrees of freedom reveals a model of conformational interconversion. The model implies gearing motion of the two PC3 fragments alternating with stepwise inversions of the helicities of the PPh3-propellers.  相似文献   

5.
Mechanisation came early to clinical chemistry and has passed through a number of phases. Selective multichannel machines, usually discrete analysers with their associated mechanical complexities, have become popular; the simplicity and reliability of flow analysers has been lost. Flow injection offers new opportunities to develop simple selective machines. Sample waste is avoided in the controlled-dispersion flow analyser; the slug of sample is picked up by a probe, the volume being metered by the peristaltic pump driven by a stepping motor under computer control. Reagent waste is avoided by a similar system and use of merging zones. Very economical operation is thus possible and acceptable precision is attained. Various features of the technique, including prolonged incubation, use of kinetic methods to minimise the need for blanks, and application of different detectors are discussed in the context of clinical assays. Anomalous behaviour of particulate matter in flow streams and the changing shape of sample slugs in stationary streams are described. The application of flow-injection systems in clinical chemistry is extremely promising.  相似文献   

6.
Capillary electrophoresis coupled with frontal analysis was applied to the study of enantioselective binding of verapamil (VER) to plasma lipoproteins. The drug-lipoprotein mixed solution, which had been in the binding equilibrium, was hydrodynamically introduced into a non-coated fused-silica capillary. Since VER is positively charged in the neutral run buffer (pH 7.4), the unbound VER enantiomers migrated toward the cathodic end much faster than negatively charged lipoproteins and their bound forms. Once unbound VER migrated apart from lipoprotein, the bound VER was quickly released from the protein to maintain the binding equilibrium. Thus, VER migrated as a zone through the capillary and gave a trapezoidal peak with a plateau region on the electropherogram. The VER concentration in this plateau region was equal to the unbound VER concentration in the initial sample solution. It was found that the bindings of VER to high-density lipoprotein (HDL), low-density lipoprotein (LDL) and oxidized LDL were not site-specific and not enantioselective. Partition-like binding to lipid part of these lipoproteins seemed to be dominant. The total binding affinities of LDL to VER were about seven-times stronger than those of HDL, and the oxidation of LDL by copper ion enhanced the binding affinities significantly.  相似文献   

7.
Chondrocytes are the only cell type present in mature articular cartilage (2-5% of total tissue). The biological activities of the chondrocyte population are regulated by genetic, biologic and biochemical factors, as well as environmental factors (stress, flow and electric field). Although compressive forces within joint articular cartilage are required for maintenance of the normal composition of articular cartilage, there is a lack of knowledge about the number of pressure-related proteins expressed in articular cartilage. Two-dimensional gel electrophoresis (2-DE) and high-performance liquid chromatography-electrospray/tandem mass spectrometry (HPLC/ESI-MS/MS) were used to identify the levels of pressure-related proteins expressed by chondrocytes grown in the presence or absence of hydrostatic pressure. A total of 266 spots were excised from the gels and analyzed by HPLC/ESI-MS/MS. Functional classification of up-regulated proteins indicated that energy and protein fate were the main biological processes occurring in pressurized chondrocytes. Furthermore, membrane-bound transferrin-like protein p97, a marker of chondrocyte differentiation, was only expressed in chondrocytes under hydrostatic pressure. These data suggest that hydrostatic pressure can induce cell differentiation by increasing the expression level of energy metabolism- and protein fate-related proteins, indicating that hydrostatic pressure may be needed for normal biosynthesis and differentiation of articular chondrocytes.  相似文献   

8.
The structural stability of hen egg white lysozyme in solution and adsorbed to small colloidal silica particles at various surface concentrations was investigated using hydrogen-deuterium (H/D) exchange in combination with mass spectrometry (HDX-MS) and differential scanning calorimetry (DSC). The combination of HDX-MS and DSC allows a full thermodynamic analysis of the lysozyme structure as both the enthalpy and the Gibbs free energy can be derived from the various measurements. Moreover, both HDX-MS and DSC provide information on the relative structural heterogeneity of lysozyme in the adsorbed state compared to that in solution. Results demonstrated that at high surface coverage, the structural stability of lysozyme was only marginally affected by adsorption to silica particles whereas the unfolding enthalpy decreased by more than 10%, meaning that the entropy of lysozyme increased with a similar value upon adsorption. Furthermore, the structural heterogeneity increased considerably. At lower surface concentrations, the structural heterogeneity increased further whereas the enthalpy of unfolding decreased. Further analyses of the HDX-MS experiments clearly indicated that folding/unfolding of lysozyme occurs through a two-domain process. These two domains had a similar amount of structural elements and a difference in stabilization energy of 8 kJ/mol, regardless if lysozyme was in solution or adsorbed to silica.  相似文献   

9.
A first attempt has been made to interpret physicochemical data from potentiometric titration analysis in accordance with the complete measurement-uncertainty budget approach (bottom-up) of ISO and Eurachem. A cause-and-effect diagram is established and discussed. Titration data for arsenazo III are used as a basis for this discussion. The commercial software Superquad is used and applied within a computer-intensive resampling framework. The cause-and-effect diagram is applied to evaluation of seven protonation constants of arsenazo III in the pH range 2–10.7. The data interpretation is based on empirical probability distributions and their analysis by second-order correct confidence estimates. The evaluated data are applied in the calculation of a speciation diagram including uncertainty estimates using the probabilistic speciation software Ljungskile.This paper is dedicated to the memory of the late Pope John Paul II, Dr honoris causa of Adam Mickiewicz University.  相似文献   

10.
Differential thermal analysis (DTA) and thermogravimetry (TG) are applied to various fields of mineral science. The present work illustrates the importance of the application of thermal analysis to mineral synthesis, to the determination of the mechanism and optimum temperature of synthesis and the thermal behaviour of minerals and starting materials. Selected examples of applications in this field are given. These include DTA studies of the synthesis of topaz, cryptohalite, wulfenite, perovskite, scheelite and the refractory materials, baddeleyite and corundum. Thermal analysis is proved to be an important and valuable tool in mineral synthesis.  相似文献   

11.
Thermal analysis is a convenient means of characterizing the soot used as a source of the carbon clusters, the extracted mixture of fullerenes, and the individual clusters themselves. TG in an inert atmosphere will rapidly assay the volatile fractions, presumably the lower molecular weight clusters. TG in oxygen indicates — a slight weight gain for the soots and clusters prior to their combustion.DSC in oxygen is used to determine the heat of combustion for the separated C60 and C70 materials. The combustion occurs around 300°C for the clusters. There is a small exothermic peak before this which is attributed to the oxidation associated with the slight weight gain. The heats of combustion measured are –18.7 and –21.0 kJ·mol–1 for the C60 and C70 respectively.MS-EGA indicates the loss of small amounts of water and argon at temperatures around 250°C in vacuum and of solvent at about 350°C prior to sublimation.
Zusammenfassung Thermoanalyse ist ein praktisches Hilfsmittel zur Charakterisierung von Ruß als Quelle für Kohlenstoffcluster, extrahierte Gemische von Fullerenen und die individuellen Cluster an sich. TG in einer inerten Atmosphäre ergibt schnell die flüchtigen Fraktionen, wahrscheinlich die niedermolekularen Cluster. TG in Sauerstoff zeigt einen leichten Gewichtszuwachs für Ruß und Cluster vor ihrer Zersetzung.DSC in Sauerstoff wurde angewendet, um die Verbrennungswärme der getrennten C60 und C70 Materialien zu ermitteln. Die Verbrennung erfolgt für die Cluster bei etwa 300°C. Davor kann ein kleiner exothermer Peak beobachtet werden, welcher der Oxidation in Verbindung mit dem geringen Gewichtszuwachs zugeschrieben wird. Die gemessenen Verbrennungswärmen betragen –18.7 und –21.0 kJ·mol–1 für C60 bzw. C70.MS-EGA zeigt den Verlust von geringen Mengen an Wasser und Argon bei Temperaturen von etwa 250°C in Vakuum und von Lösungsmittel bei etwa 350°C, bevor die Sublimation eintritt.
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12.
We used the variable number tandem repeat (VNTR) polymorphism and the ten short tandem repeat (STR) polymorphisms to study a number of disputed paternity cases in the Japanese population. For the determination of VNTR locus (D1S80) and the ten STR loci (vWA, F13B, TH01, TPOX, CSF1PO, F13A01, LPL, D3S1744, D12S1090, D18S849) we used polymerase chain reaction (PCR) amplification and the vertical polyacrylamide gel electrophoresis technique followed by SYBR green I staining. The irregular repeats were analyzed by sequencing from bands of vertical polyacrylamide gel electrophoresis using the latest gene analyzing equipment, the ABI PRISM 310 Genetic Analyzer. The probable genotypes of the deceased putative father were deduced by Komatu's method from the genotypes of the widow and the genotypes of their children. The calculation of paternity probability used the Essen-Moller formula and Bayes's theorem. Calculated in eleven loci, the distinguishing probabilities (DP) and the mean exclusion chance (MEC) were 0.9999 and 0.9989, respectively. Therefore, information obtained from eleven DNA polymorphisms is enough to determine paternity plausibility.  相似文献   

13.
Summary A simple method for the determination of five chlorophenoxyalkane carboxylic acids in cereals is described. After alkaline hydrolysis the samples are extracted on-line. The acids are methylated and cleaned up over small silicagel columns. The gaschromatographic determination is performed using packed and capillary columns. The recovery yields are between 86% and 100%.  相似文献   

14.
Some typical applications of long-term/low-level exposure (LLE) is presented including in vivo LLE study on rats and in vitro experiments on some metal binding components as well as on cadimium binding protein.  相似文献   

15.
The approach of thermal analysis and explosion in relation to safety science is based on investigation methods in the mining and chemical industries. Once adapted to the particularities of foods, these methods correspond well to the needs of the food industry. Thus, thermal analysis and explosion simulation techniques as part of safety science (or loss prevention) participate to a large extent in the prevention of incidents and accidents by helping to take preventive measures.The author gratefully acknowledges P. Lambelet for many helpful discussions and I. Horman for reviewing this text.  相似文献   

16.
XRF技术在无铅化工艺产品分析中的应用   总被引:1,自引:1,他引:0  
介绍了XRF技术对无铅化产品和无铅化工艺中铅的快速无损分析的原理及其在实际检测中的应用. 采用自行研制的XRF-1000X射线荧光仪对无铅焊料及镀层进行快速无损分析, 其过程简单、结果准确、精度高.  相似文献   

17.
We have demonstrated an informatics methodology for finding correlations between the full profile Fourier transform infrared spectra of polycrystalline 3C‐silicon carbide (poly‐SiC) films and their growth conditions, thereby developing high‐throughput structure‐process relationships. Because SiC films are a structural element in photonic sensors, this paper focuses on the interpretation of their optical response, the multivariate tracking of critical processing pathways, and the identification of controlling processing mechanisms. Using principal component analysis, we have developed a data analysis tool to aid in the assessment of the relative contributions of experimental parameters in low‐pressure chemical vapor deposition processes to optical responses on the basis of the size of eigenvalues of the spectral data set. The applied methodology for identifying spectral relationships of stoichiometry, dopant chemistry, and microstructure of poly‐SiC provides more effective guidelines to manipulate optical responses by controlling multiple experimental parameters. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

18.
Summary Fundamental aspects of information theory and its usefulness for qualitative analysis are discussed in view of the applications described so far in the literature. General expressions for the uncertainty, information, equivocation and information content are described and related to the more commonly used expressions of the information parameters.It is shown that the information content (or equivocation) can serve — with certain restrictions — as an important criterion for the evaluation, selection or optimization of analytical procedures.The information theoretical concepts are easy to apply to one-channel identification or classification procedures. However, when multi-channel procedures (combinations of one-channel procedures) are involved, a straightforward use of information theory is to a large extent restricted by the excessive computations. Therefore, the further development of simple methods for the calculation of reliable estimates of information contents and of optimization strategies enabling the calculation of only small numbers of information contents, is of great importance for the future use of information theory in qualitative analysis.
Anwendung der Informationstheorie in der qualitativen Analyse
Zusammenfassung Grundlegende Aspekte der Informationstheorie und ihre Anwendbarkeit für die qualitative Analyse werden unter Berücksichtigung der bisher in der Literatur beschriebenen Anwendungen besprochen. Allgemeine Ausdrücke für Unsicherheit, Information, Äquivokation und Informationsgehalt werden beschrieben und ihre Beziehung zu den gebräuchlicheren Ausdrücken für die Informationsparameter wird angegeben.Es wird gezeigt, daß der Informationsgehalt (oder die Äquivokation) — unter bestimmten Bedingungen — als ein wichtiges Kriterium für die Auswertung, Selektion oder Optimierung von analytischen Verfahren dienen kann.Die Grundlagen der Informationstheorie können auf einfache Weise für einkanalige Identifizierungsoder Klassifizierungsverfahren angewendet werden. Wenn es sich jedoch um mehrkanalige Verfahren (Kombinationen von Einkanal-Verfahren) handelt, wird die Anwendung der Informationstheorie in hohem Maße durch übermäßige Berechnungen begrenzt.Die weitere Entwicklung von einfachen Verfahren für die Berechnung zuverlässiger Schätzungen von Informationsgehalten und von Optimierungsstrategien, die die Berechnung einer beschränkten Anzahl von Informationsgehalten erfordern, ist deshalb von großer Wichtigkeit für die künftige Anwendung der Informationstheorie in der qualitativen Analyse.
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19.
Summary Neutron activation analysis technique, using Au as flux monitor, was applied to determine element concentrations of Ca, K, Na, Mg, Mn and Sr in certified reference material (NIST 1400 Bone Ash). The results were compared with those using comparative INAA and they were compatible. The same results were obtained using the recommended k0 factors, in order to obtain the activation cross section as input in concentration for the same reference material. Some applications in the health area aiming clinical evaluation in bone samples of medium and small-sized animals were performed and the viability of using this methodology was discussed.  相似文献   

20.
Indirect photometric chromatography, which couples analyte separation by ion exchange with indirect photometric detection, is applied to the analysis of complex solutions encountered in the pharmaceutical industry. Applications of primary interest include simultaneous acetate, lactate, chloride, or phosphate determinations, a bisulfite/sulfate assay, and quantitation of trace levels of chloride in deionized water. Three commercially available ion chromatography columns are studied for their suitability in these applications. Due primarily to (A) the acid-base chemistry of the phosphate and bisulfite ions, (B) the need to stabilize the readily oxidized bisulfite, and (C) resin stability at high pH, the column packed with a polymer-based resin is capable of producing analytically superior separations of Cl-, HPO4-2, and matrix components and of SO3-2/SO4-2 in the samples of interest. Under rigid relative concentration conditions, the columns packed with a silica backbone resin are capable of separating acetate, lactate, Cl-, and H2PO4- with baseline resolution and are effective for determining Cl- levels at concentrations of less than one part-per-million.  相似文献   

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