Quality assessment of crude and processed ginger by high‐performance liquid chromatography with diode array detection and mass spectrometry combined with chemometrics

A sensitive, simple, and validated high‐performance liquid chromatography with diode array detection and mass spectrometry detection method was developed for three ginger‐based traditional Chinese herbal drugs, Zingiberis Rhizoma, Zingiberis Rhizome Preparatum, and Zingiberis Rhizome Carbonisata. Chemometrics methods, such as principal component analysis, hierarchical cluster analysis, and analysis of variance, were also employed in the data analysis. The results clearly revealed significant differences among Zingiberis Rhizoma, Zingiberis Rhizome Preparatum, and Zingiberis Rhizome Carbonisata, indicating variations in their chemical compositions during the processing, which may elucidate the relationship of the thermal treatment with the change of the constituents and interpret their different clinical uses. Furthermore, the sample consistency of Zingiberis Rhizoma, Zingiberis Rhizome Preparatum, and Zingiberis Rhizome Carbonisata can also be visualized by high‐performance liquid chromatography with diode array detection and mass spectrometry analysis followed by principal component analysis/hierarchical cluster analysis. The comprehensive strategy of liquid chromatography with mass spectrometry analysis coupled with chemometrics should be useful in quality assurance for ginger‐based herbal drugs and other herbal medicines.     

Comparison of photon activation analysis with other modern analytical methods as tools for the solution of actual analytical problems

A 35 MeV linear electron accelerator is used to investigate how far photon activation analysis can be used within the broad spectrum of analytical methods applied in BAM. The irradiation facilities are described. Examples are given for the application of PAA in the analysis of oxygen in metals and compared with conventional heat extraction and other nuclear analytical methods. It is further shown that PAA is a very useful tool for the analysis of traces of noble metals in Cu compared with other methods. Finally the possibilities of PAA in the field of multielement analysis are demonstrated taking ancient roman potsherds and bronze as examples. The results are compared with those of XRF and AAS. It is concluded that PAA is a valuable tool in the analysis of light elements with at least partly unique possibilities, that it can serve as an independent method for the certification of Reference Materials in many cases and that PAA can be very useful applied for multielement analysis.     

面向新世纪的冶金材料分析

21世纪冶金材料分析面临复杂体系中痕量元素分析、冶金材料原位分析以及在线实时分析等三大问题。本文对这三方面的发展趋势进行了评述。     

A spray technique for the determination of membrane diffusion and distribution coefficients by the time-lag method: evaluated for electrolyte transport through charged and uncharged membranes

Using solution sprays, a sharp concentration step may be effected at the surface of a membrane in less than 0.1 sec. This technique allows the time-lag method to be used to determine rapidly both solute permeability and diffusion coefficient in a single experiment. From the mathematical analysis of diffusion into a cell with finite collecting volume, limiting conditions are derived which define experimental conditions under which the conventional linear, steady state analysis of time lag will be valid. These limiting conditions were used to determine the dimensions of the experimental diffusion cell. Diffusion, permeability and distribution coefficients were measured for a variety of electrolytes in both charged and uncharged membranes and shown to be in good agreement with conventional methods. A Donnan analysis is given by which the charged nature of an unknown membrane may be assessed precisely and rapidly.     

Proton, Photon and Neutron Activation Analysis for the Determination of Stable Isotopes of Gadolinium in Human Blood Plasma

The biokinetics of radioactive substances can be studied using stable tracers. For the highly radiotoxic actinides, for which no stable isotopes are available as tracers, the use of stable isotopes of lanthanides as chemically related surrogates has been suggested. In this work, the possibility of using activation analysis with protons, photons, or thermal neutrons for the determination of single stable isotopes of gadolinium in biological samples has been tested. All the techniques show very good linearity response, and may be considered as complementary. Whereas activation analysis with protons is recommendable for the simultaneous determination of two different isotopes, neutron and photon (gamma) activation analysis should be chosen whenever a better sensitivity or simplicity of the analysis is required.     

原位电离与小型质谱在公共安全领域的应用

质谱作为一种具有高准确度、高灵敏度、高选择性的检测仪器,在公共安全领域有着重要的应用前景.公共安全领域的需求主要涉及毒品、毒物、爆炸物等化学物质的现场快速检测,因其影响广泛,检测结果需非常准确.作为实验室分析仪器,质谱的准确性和速度能满足公共安全的应用需求,但作为现场快速检测的仪器仍需要一定改进.现场快速检测一方面要求...     

Conformational analysis of oligosaccharides in solution

A complete understanding of the role of carbohydrates in biological systems is to a large extent dependent on the information available about the equilibrium mixture and about the preferred conformation of the carbohydrate molecules in solution. The conformational analysis offers a tool which can determine all possible conformations which influence the solution behavior of carbohydrates. This paper attempts to survey the progress in the theoretical conformational analysis of saccharides in solution. The conformational analysis will be discussed in detail both with respect to the strategy for the investigation of conformational properties but also with regard to the quality of the method used for calculations of the energy of the isolated molecule and free energy of solvation. Finally, examples will be given to illustrate how the methods of conformational analysis can be used to estimate the solution behavior of cyclic model compounds of carbohydrates 2-methoxytetrahydropyran, monosaccharide D -glucopyranose, and two disaccharides; β-maltose and β-cellobiose.     

New Adventures in Thermal Analysis

This paper describes recent advances in thermal analysis instrumentation which combine the high resolution imaging capabilities of the atomic force microscope with physical characterisation by thermal analysis. Images of the surface may be obtained according to the specimen's thermal conductivity and thermal expansivity differences in addition to the usual topographic relief. Localised equivalents of modulated temperature differential scanning calorimetry, thermomechanical and dynamic mechanical analysis have been developed with a spatial resolution of a few micrometres. A form of localised thermogravimetry-evolved gas analysis has also been demonstrated. The same instrument configuration can be adapted to allow IR microspectrometry at a resolution better than the optical diffraction limit. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rapid,automatic, high capacity dumas determination of nitrogen

Chemical and physical processes which take place in the Carlo Erba ANA 1400 automatic nitrogen analyzer were investigated. The instrument and its sampler were modified. Several drums with samples can be stacked upon each other for automatic analysis.About 100 analyses can be carried out in a working day, and the instrument can be loaded with further 100 or more samples for automatic analysis overnight.One analysis takes 5 min and the analyst can present a result within less than 10 min after that he has obtained the specimen for analysis. A minimum of labor is required. The instrument does clean work, requires very little laboratory space, and causes no environmental hazards.A series of 20 analyses of pure organic nitrogen-containing compounds gave a standard deviation from theory of 0.08% N. Examples of nitrogen determinations in mineral oils are reported. A cyclone mill, Retsch ZM1 was found to grind 200 g of grains, hay, peat, and other materials of agricultural interest in about 1 min to a powder, fine enough for analysis with the ANA. Examples of such analyses are reported.The method can favorably replace the Kjeldahl method in many instances of industrial, agricultural, and food analysis.     

Advantages and limitations of combining separation techniques with voltammetry

In this review the combination of voltammetric methods of analysis with separation techniques, such as electrochemical separations, extractive separations, chromatography, electrochromatography, electrophoresis, volatilization and coprecipitation is critically discussed. Based on available publications and their own experience, the authors try to evaluate different separation techniques in view of future developments, paying special attention to extraction methods. For organic analysis, chromatography and electrophoresis with voltammetric detection are considered to be especially attractive while for stripping analysis, major progress is expected to be made in the development of electrodes and electronic equipment. Extraction, coprecipitation and volatilization will be of minor significance.     

Topological data analysis: A promising big data exploration tool in biology,analytical chemistry and physical chemistry

An important feature of experimental science is that data of various kinds is being produced at an unprecedented rate. This is mainly due to the development of new instrumental concepts and experimental methodologies. It is also clear that the nature of acquired data is significantly different. Indeed in every areas of science, data take the form of always bigger tables, where all but a few of the columns (i.e. variables) turn out to be irrelevant to the questions of interest, and further that we do not necessary know which coordinates are the interesting ones. Big data in our lab of biology, analytical chemistry or physical chemistry is a future that might be closer than any of us suppose. It is in this sense that new tools have to be developed in order to explore and valorize such data sets. Topological data analysis (TDA) is one of these. It was developed recently by topologists who discovered that topological concept could be useful for data analysis. The main objective of this paper is to answer the question why topology is well suited for the analysis of big data set in many areas and even more efficient than conventional data analysis methods. Raman analysis of single bacteria should be providing a good opportunity to demonstrate the potential of TDA for the exploration of various spectroscopic data sets considering different experimental conditions (with high noise level, with/without spectral preprocessing, with wavelength shift, with different spectral resolution, with missing data).     

新工科背景下分析化学中质量保证和质量控制的教学改革探究*

通过对目前分析化学教学中存在问题的分析,探究了新工科背景下分析化学专业中关于质量保证和质量控制方面的教学改革,提出了增设“分析化学中的质量保证和质量控制”或者类似的课程的建议,指出分析化学的教学应该围绕整个分析过程展开,并将分析化学中的质量保证和质量控制知识融入分析全过程中,注重理论课程与实践课程相互结合的同时更加强调应用性,增强学生的实践能力和分析问题、解决问题的能力。此外,分析化学教学重在“分析”,要与分析实验室/检测机构保持紧密联系,应建立以市场为导向、以技术为核心的教学活动,从而实现为社会不断培养与时俱进的分析人才的教育目标。     

Effect of polymer matrix and glycerol on rapid single-strand conformation polymorphism analysis by capillary and microchip electrophoresis for detection of mutations in K-ras gene

We present the rapid single-strand conformation polymorphism (SSCP) analysis by capillary and microchip electrophoresis to detect the mutations in K-ras gene. Parameters that might affect the analysis of mutation in K-ras gene, such as the polymer and the additive in the sieving matrix, have been studied systematically. Under the optimal conditions, the analysis of seven mutants of K-ras gene could be finished within 10 min by capillary electrophoresis (CE). Furthermore, with the wild-type gene as the inner standard, the analysis accuracy of mutations could be improved. In addition, by studying the properties of polymer solutions, the matrix suitable for microchip electrophoresis was found, and the detection of mutations in K-ras gene could be further shortened to 1 min.     

Determination of wheat quality by mass spectrometry and multivariate data analysis

Multivariate analysis has been applied as support to proteome analysis in order to implement an easier and faster way of data handling based on separation by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The characterisation phase in proteome analysis by means of simple visual inspection is a demanding process and also insecure because subjectivity is the controlling element. Multivariate analysis offers, to a considerable extent, objectivity and must therefore be regarded as a neutral way to evaluate results obtained by proteome analysis.Proteome analysis of storage proteins from the wheat gluten complex based on two-dimensional electrophoresis and analysis of the N-terminal sequence has revealed a protein homologous to gamma-gliadins, tentatively associated with quality and within the molecular weight range 27-35 kDa. Further examinations of gliadin data based on mass spectrometry revealed that quality among wheat varieties could be determined by means of principal component analysis. Further examinations by interval partial least squares made it possible to encircle an overall optimal molecular weight interval from 31.5 to 33.7 kDa. The use of multivariate analysis on data from mass spectrometry has thus shown to be a promising technique to minimize the number of two-dimensional gels within the field of proteome analysis.     

Sonoelectroanalysis in Acoustically Emulsified Media: Zinc and Cadmium

Dithizone (diphenylthiocarbazone) dissolved in chloroform was employed as a ligand for the solvent extraction of either cadmium or zinc from aqueous media. Acoustic emulsification was shown to be effective both in extraction and recovery or ‘back extraction’ with a fresh clean aqueous solution. Quantitative analysis of cadmium or zinc removed via double sono‐extraction from aqueous media hostile to voltammetric analysis proceeded via sono‐square wave anodic stripping voltammetry (sono‐SWASV), resulting in high sensitivity in the relatively clean medium. This technique was shown to be viable for the quantification of cadmium from surfactant containing media where direct electroanalytical techniques fail. The method was also applied to the analysis of zinc in commercial shampoo and toothpaste, giving results in close agreement with those obtained from independent analysis. Biphasic sono‐extraction synergistically coupled with sono‐SWASV therefore presents an attractive technique for cadmium or zinc analysis in electrode passsivating media. The technique likely removes contaminants present in the test solution since these will ‘prefer’ to remain in the initial aqueous phase, or will transfer to the extracting organic phase, but are unlikely to be doubly transferred into the clean final aqueous phase.     

Tetramethylammonium hydroxide thermochemolysis for the analysis of cellulose and free carbohydrates in a peat bog

We have compared TMAH thermochemolysis with the classical method using acid hydrolysis for carbohydrates analysis in a peat core. Even if TMAH thermochemolysis does not analyse hemicellulosic carbohydrates and discriminate each individual carbohydrate sensu stricto, it allows the analysis of a cellulose pool hidden to acid hydrolysis and the specific analysis of free and terminal carbohydrates. Simple direct comparisons of thermochemolysis data with data generated from acid hydrolysis cannot be done because of the different mechanisms involved in each process. TMAH thermochemolysis must be viewed and used as a pertinent and complementary method for the analysis of carbohydrates protected and trapped by the organic matter in complex environmental systems.     

Critical evaluation of screening techniques for emerging environmental contaminants based on accurate mass measurements with time‐of‐flight mass spectrometry

Emerging contaminants from wastewater effluent samples were analysed, using posttarget and nontarget analysis techniques. The samples were analysed with an ultra performance liquid chromatograph‐time‐of‐flight mass spectrometer (UPLC‐TOF‐MS), and the resulting data were processed with commercial deconvolution software. The method works well for posttarget analysis with prior information about the retention times of the compounds of interest. With positive polarity, 63 of 66 compounds and with negative polarity, 18 of 20 compounds were correctly identified in a spiked sample, while two compounds of a total of 88 fell out of the mass range. Furthermore, a four‐stage process for identification was developed for the posttarget analysis lacking the retention time data. In the process, the number of candidate compounds was reduced by using the accurate mass of selected compounds in two steps (stages 1 and 2), structure–property relationships (stage 3) and isotope patterns of the analytes (stage 4). The process developed was validated by analysing wastewater samples spiked with 88 compounds. This procedure can be used to gain a preliminary indication of the presence of certain analytes in the samples. Nontarget analysis was tested by applying a theoretical mass spectra library for a wastewater sample spiked with six pharmaceuticals. The results showed a high number of false identifications. In addition, manual processing of the data was considered laborious and ineffective. Finally, the posttarget analysis was applied to a real wastewater sample. The analysis revealed the presence of six compounds that were afterwards confirmed with standard compounds as being correct. Three psycholeptics (nordiazepam, oxazepam and temazepam) could be tentatively identified, using the identification process developed. Posttarget analysis with UPLC‐TOF‐MS proved to be a promising method for analysing wastewater samples, while we concluded that the software for nontarget analysis will need improvement before it can be used in environmental analytical work with LC‐TOF‐MS systems. Copyright © 2012 John Wiley & Sons, Ltd.     

A reflectometric sensor for ammonia and hydrocarbons

Summary Optical reflection measurements in the visible wavelength range may be used for fast analysis of changes in optical thickness of thin polymer layers caused by swelling of the film in contact with various gaseous analytes. Including an absorbing species into the sensitive layer, the applicability of this sensor can be extended to gases with acidic or basic character. The method is demonstrated using bromocresol purple as pH-indicator in a polydimethylsiloxane layer. Principal component analysis is used for qualitative analysis of a two-component gas.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Diagnosis of lung cancer based on metal contents in serum and hair using multivariate statistical methods

The classification of normal and cancer groups with four multivariate methods according to metal contents in serum and hair samples has been discussed in the present paper. Results show that the four multivariate methods, stepwise discrimination analysis, principal components analysis, hierarchical cluster analysis, and stepwise cluster analysis can distinguish the two groups correctly. The independent samples of both normal and cancer groups were tested and can be distinguished correctly by the four methods. Therefore, these methods can be used as an aid for diagnosis of lung cancer according to the metal contents in serum and hair samples.