Synthesis of n-(phenoxathiin-2-carbonyl)-or N-(thianthrene-2-carbonyl)-N′-arylthioureas

The reactions of phenoxathiin-2-carbonyl-or thianthrene-2-carbonyl-isothiocyanates with certain primary amines lead to the formation of corresponding N-substituted-N-hetaroylthiocarbamides. The aforementioned isothiocyanates were obtained in situ by reactions of phenoxathiin-2-or thianthrene-2-carbonyl chlorides with KSCN. The new compounds were characterized by elemental analysis and spectral data (IR,¹H and¹³C NMR).Analytical Laboratory-Biofarm, 99 Logofat Tautu Street, Bucharest, Roumania. Faculty of Pharmacy, Organic Chemistry Departament, University of Medicine and Pharmacy Carol Davila, 6 Traian Vuia Street, Bucharest, Roumania, Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, 76233, RoumaniaPublished in Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1681–1686, December, 1999.     

Training and opportunities for Analytical Chemists in Switzerland

Summary The development during the past 5 years (results of an enquiry running from 1973–1978) is shown for the following: A. Demand for Analytical Chemists in some important Swiss companies; B. Interest in training chemists specializing in Analytical Chemistry in Swiss universities; C. Teaching in Analytical Chemistry, in particular the University of Geneva.Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

Dioxirane oxidation of benzopyrans,benzothiopyrans, and related compounds

Dioxiranes are shown to be powerful and convenient oxidation agents for benzopyrans, benzothiopyrans, and , -unsaturated ketones.Department of Organic Chemistry, KOssuth Lajos University, Egyetem ter 1, H-4010 Debrecen, Hungary. Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany. Technical Analytical Research Group of the Hungarian Academy of Sciences, Institute of General and Analytical Chemistry. Technical Univeristy, St. Gellert ter 4, H-1111 Budapest, Hungary. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1345–1349, October, 1995. Original article submitted July 16, 1995.     

Assessment of Four Inter-Comparison Exercises in Organic Elemental Analysis

 Four inter-comparison exercises on organic elemental analysis were carried out between 1997 and 2001 by the Department of Analytical Chemistry of the University of Barcelona, together with the Microanalysis Service and the Institute of the Marine Sciences, which both belong to the CSIC in Barcelona, and the University of A Coru?a. More than sixty laboratories participated in these exercises. Here we describe the design and characteristics of the trials, the samples and the homogeneity tests applied. We report the results obtained for the analysis of carbon, hydrogen, nitrogen, sulphur and oxygen, their statistical analysis, and the most relevant aspects of the technical discussion meetings. Received December 20, 2001; accepted March 18, 2002; published online July 22, 2002     

A review of liquid chromatography in environmental pesticide analysis

Summary The use of liquid chromatography in environental pesticide analysis is reviewed. In addition to classical UV and electrochemical detectors, detection systems such as mass spectromytry and gas chromatographytype detectors are discussed. The applicability of supercritical fluid chromatography to pesticide analysis is also reviewed.Presented at the 18th International Symposium on Environmental Analytical Chemistry, Barcelona 5–8 September, 1988.     

Thermodynamics of lonization of aqueous lodic acid,an “almost-strong” electrolyte

We have made calorimetric measurements of enthalpies of dilution of aqueous iodic acid and have used these results for evaluation of the standard enthalpy of ionization of HIO₃(aq.). We have also made calorimetric measurements of enthalpies of addition of perchloric acid solution to aqueous solutions of KIO₃, KNO₃, NaIO₃, and NaNO₃ and have used these results to obtain further values for the standard enthalpy of ionization of HIO₃(aq.). On the basis of all these results, we have selected H^o=–660±125 cal-mole^–1 as the best available standard enthalpy of ionization of HIO₃(aq.) at 298.15°K, compared to the previously accepted –2400 cal-mole^–1. Using the best available K=0.157 for ionization, we also obtain G^o=1097 cal-mole^–1 and S^o=–5.9 cal-^oK^–1-mole^–1 for ionization of HIO₃(aq) at 298.15°K.On study leave from Department of Inorganic and Analytical Chemistry, LaTrobe University, Bundoora, Victoria, 3083, Australia, to University of Lethbridge.On study leave from Department of Chemistry, University of Wollongong, Wollongong, N.S.W. 2500, Australia, to University of Lethbridge.     

Anodic stripping coulometry with collection for absolute trace analysis of lead, using flow-through electrochemical cells with porous working electrodes

Summary Flow-through electrochemical cells with porous working electrodes made of crushed reticulated vitreous carbon and plated with mercury were used for absolute analysis of trace amounts of lead by anodic stripping coulometry with collection (ASCWC) in a flow system. The role of mercury coating, flow rate and pH were investigated. The coulombic content of the collection peak corresponded to the theoretical values calculated by Faraday's law in a concentration range from about 10^–9 to 10^–6 mol/l. The relative error and the relative standard deviation was +0.15% and 0.8%, respectively for 2×10^–6 mol/l analyte concentration. The absolute detection limit (3 s) was 0.1 ng of Pb, the linear response range 7×10⁴. One leave from: Department of Analytical Chemistry, Slovak Technical University, CS-812 37 Bratislava, Czechoslovakia     

Analytical Chemistry — today''s definition and interpretation

Conclusion Since every science is defined as a way of knowledge accumulation and theory formulation, the magnificent cognitive power of Analytical Chemistry cannot be disregarded by any natural scientist. Therefore the state of the art in the field of Analytical Chemistry has a strong impact on other scientific disciplines. Without the cognitive feedback of analysis, no synthesis, no high-tech process, or pollution control actions are possible. Since the whole perception of the properties and laws of the material world are so strongly dependent on the level of performance of Analytical Chemistry it has become a self-reliant, chemical subdiscipline. Analytical Chemistry also includes a tremendous economic side, directly through the market for analytical instruments and, above all, indirectly through decisions taken in industry and the society as a whole based on analytical results. Because nearly a third of all chemists work in the field of Analytical Chemistry, it should be taught at a sufficient level at every University which has a Chemistry Department, in order to ensure the continued knowledge base which this subdiscipline uniquely provides.     

On-line electrochemical preconcentration of manganese for graphite furnace atomic absorption spectrometry using a flow-through electrochemical cell

A flow system incorporating a 2-electrode electrochemical microcell with a working electrode made from crushed reticulated vitreous carbon and a graphite furnace AAS instrument was used for the preconcentration and determination of trace amounts of Mn. The sample, rinsing and elution solutions were pneumatically transported through the system. Mn²⁺ ions can be quantitatively deposited both anodically and cathodically at a voltage of +1.5 to + 3 V and –2.5 to –4V, respectively applied to the cell. Samples of 0.1 to 1 ml volume were analyzed within 5–10 min. The limits of detection and determination were 8.7 and 29 pg, respectively. The reproducibility was 1.5 to 5%. The electrochemical behaviour of Mn in the flow system was studied by using a 3-electrode flow-through cell coupled on-line to a flame AAS instrument.On leave from Department of Analytical Chemistry, Slovak Technical University, CS-812 37 Bratislava, Czechoslovakia     

Spectra and structure of silicon containing compounds

The Raman (50 to 3200 cm^–1) and infrared (50 to 3500 cm^–1) spectra of chlorodimethylmethoxysilane, Cl(CH₃)₂SiOCH₃, in the vapor and solid phases have been recorded. Raman spectra of the liquid including depolarization ratios have also been recorded. Optimized geometries and conformational stabilities have been obtained from ab initio calculations utilizing the RHF/3–21G* and RHF/6–31G* basis sets. The calculations from both of these basis sets indicated the gauche conformer to be significantly more stable than the trans conformer. Since the gauche has twice the multiplicity of the trans form it is unlikely that the trans conformer will be detected in the fluid phases at room temperature. This is supported by the fact that no infrared or Raman bands were found to vanish in the spectra of the crystalline solid. The vibrational frequencies have been calculated using appropriate scaling factors, and the vibrational spectra are interpreted in detail. The results have been compared with those obtained for some related molecules.Dedicated to Professor Dr. H. Kriegsmann on the occasion of his 70th birthdayFor part XX, see J Raman Spectrosc 26:in press (1995)Analytical R/D Department, Organic Products Division, Miles Inc., Bushy Park Plant. Charleston, SC 9411, USAChemistry Department, Mu'tah University, P.O.Box 7, Mu'tah-Karak, JordanDepartment of Chemistry, Moscow State University, Moscow, B-234, RussiaDepartment of Ceramic Engineering, Inha University, Nam-Ku, Incheon 160, KoreaDepartment of Chemistry, University of Oslo, P.O.Box 1033, 0315 Oslo, Norway     

International student competitions in Analytical Chemistry

Summary Competition can play a very positive role of university, stimulating students to extra efforts. The international student competition in Analytical Chemistry as performed at Belgrade university is discussed in detail.Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

Education and training of Analytical chemists in Yugoslavia

Summary There are twenty chemistry departments at Yugoslavian universities and polytechnics with as many chairs of Analytical Chemistry. The individual courses show considerable differences with regard to their extent and content. The share of Analytical Chemistry is not uniform and taken as a whole not adequate. However, improvements are under way. Details of the main courses and teaching plans are given.Presented at Euroanalysis III conference. Dublin, August 20–25, 1978     

Is Analytical Chemistry an autonomous field of science?

Summary Analytical Chemistry is an autonomous branch of science. It provides empirical meaning for chemical concepts, and it has a significant component of a science of the artificial within chemistry. Processes of sample analysis and model construction that are characteristic to Analytical Chemistry, inherently involve discovering of new objects and of deeply hidden regularities. This places the discipline at the frontier of research. Moreover, it is particularly beneficial for the methodology of science to study sample analysis and model construction using the examples from Analytical Chemistry. For the same reason the methodological self-reflection of a chemist-analyst can make an original contribution to our understanding of science as a whole.

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Analytische Chemie — autonomer Zweig der Wissenschaft?

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Presented at the First International Symposium on History and Philosophy in Analytical Chemistry, Vienna, November 22–23, 1985

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On leave of absence from the University of Warsaw, Poland     

Analytical chemical methods as systems producing chemical information by inference

Summary Analytical chemical methods as systems produce chemical information about the material to be analyzed. Analytical chemical systems as semiosis consist of analytical signal production and analytical chemical signal interpretation and produce chemical information by inference in an indirect way through analytical information. From the logical point of view the chemical information produced by analytical chemical systems is only credible. Generalizing the results the idea of diagnostic systems can be introduced and the analytical chemical methods as systems are a special type of diagnostic systems.

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Chemisch-analytische Systeme zur Erlangung chemischer Informationen

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Presented at the First International Symposium on History and Philosophy in Analytical Chemistry, Vienna, November 22–23, 1985     

Teaching of Analytical Chemistry at Universities in Poland

Summary Education in Analytical Chemistry in Poland is mainly carried out at Universities and Technical Universities according to a unified curriculum. Courses on Analytical Chemistry in the second year and on instrumental analysis in the third year are compulsory for all students of chemistry. There are courses and lectures on specialized subjects in the fourth and fifth year for those who intend to subunit their thesis in Analytical Chemistry.Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

Synthesis of 1H-pyrrolo[2,3-b]phenoxathiin-2,3-dione

The title compound was obtained using the Sandmeyer reaction starting from 2-aminophenoxathiine. A new synthesis of N-methylpyrrolo[2,3-b]phenoxathiin-2,3-dione was also presented. Chemical and spectral data supporting the structure of the newly synthesized compounds were given. The isatin analogue, 1-methylpyrrolo-[2,3-b]phenoxathiin-2,3-dione-10, 10-dioxide, could not be obtained.Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, Romania. Faculty of Pharmacy, Organic Chemistry Department, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–399, March, 1998.     

Structural studies on thorium(IV)-titriplex IV-interacted 13X zeolite

A new zeolite derivative has been prepared by interacting Th(IV) and complexone in HCl medium and neutralising with aqueous ammonia. The amorphous and siliceous derivative showed a total mass loss of 29.25% in TG for stepwise dehydration, dehydroxylation and decomposition. Heats of reaction were 1167.6 J g^–1 at 88.7°C and 75.167 J g^–1 at 492.5°C for loss of volatile components and decomposition respectively.²⁹Si and²⁷Al MAS NMR spectra as well as XRD data of the derivative before and after calcination indicate presence of both four-coordinated and six-coordinated Al in varying ratios and the total loss of crystallinity.The author is grateful to Dr. Alan Dyer of the Department of Chemistry and Applied Chemistry, Salford University and to Dr. Jacek Klinowski of the Department of Chemistry, Cambridge University for providing the thermal data and NMR spectra respectively. He also acknowledges the comments received from Dr. N. Suryaprakash of the Sophisticated Instrument Facility, I.I.Sc., Bangalore on the²⁷Al and²⁹Si spectra of the derivatives.