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The isolation and characterization of bioactive compounds from medicinal plants is usually a significant challenge in phytochemical analysis because of the natural chemical complexity of plant extracts. However, there exists a need for analytical tools which can quantitatively separate and characterize the components from these biosources with greater chromatographic selectivity and lesser analytical run times that facilitate the evaluation with enhanced separation profiles. Hyphenation of thin-layer chromatography (TLC/HPTLC) with mass spectrometry (MS) is an alternative for screening herbal extracts because of its rapid analysis and ability to aid structural characterization with powerful analytical capacity. The aim of the present study was to develop a sophisticated analytical method which utilizes HPTLC–MS coupling for the chromatographic profiling and evaluation of the therapeutically important genus Piper (Piperaceae). In this study, six marker compounds, namely, trichostachine, piperine, 4,5-dihydropiperlonguminine, guineensine, pellitorine, and sesamin were analyzed and quantified in extracts of Piper nigrum L. and compared with those of Piper longum L. and Piper chaba Hunter. All the samples tested showed similar phytochemical profiles, but the contents of the active ingredients varied. Additionally, HPTLC–MS further allowed confirming the identification of the constituents in the analyzed samples with greater chromatographic selectivity where HPTLC facilitated a selective chromatographic resolution, while MS offered an efficient characterization of the target compounds in one analytical run. The study finds a potential utility in adopting HPTLC–MS as a rapid and high throughput method for the efficient quantification and identification of marker compounds from medicinal plants.

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Abstract  

Simultaneous thermal analysis (TA) and evolved gas analysis by mass spectrometry (MS) and/or Fourier transform infrared spectroscopy (FTIR) is a powerful hyphenated technique combining direct measurement of mass loss and sensitive spectroscopic analysis. In the present study the influence of several experimental parameters which may affect the quantification of FTIR signals have been studied using a combined TA-FTIR-MS system. Parameters studied include: sample mass (1-400 mg), carrier gas flow rate (25-200 mL min-1), resolution of the FTIR spectrometer (1-32 cm-1), and location of injection of the calibrating gas. MS analysis, which was not significantly affected by the experimental conditions, was used as a reference for assessing the accuracy of quantification by FTIR. The quantification of the spectroscopic signals was verified by the decomposition (NaHCO3) or dehydration (CuSO45H2O) of compounds with well-known stoichiometry. The systematic study of the parametric sensitivity revealed that spectral resolution and carrier gas flow rate, which affect the acquisition time in the IR-cell, are key parameters that must be adjusted carefully for reliable quantification. The dependence of the reliability of quantification on these parameters is illustrated and conditions leading to proper quantification are discussed. As an example, for a standard spectral resolution of 4 cm-1 and a FTIR gas cell volume of 8.7 mL, the carrier gas flow must be lower than 100 mL min-1 for warranting accurate results (relative deviation <2%). The concentration range of analyzed species is limited but can be extended by proper selection of the wavenumber regions for molecules giving strong IR signals.

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Summary

Application of chemotaxonomy to the plant kingdom can be regarded as a future challenge to the traditional binomial classification system. Construction of a classification system based on the chemical composition of plants has only recently become possible with the development of sophisticated chromatographic and hyphenated techniques. Successful chemotaxonomy can, however, be achieved only if sufficient experimental evidence is collected confirming the reproducibility of the chemical composition of plant species (irrespective of the specimen, its growing season, location of the collection site, etc.). The objective of this study was to compare, by use of gas chromatography with mass spectrometric detection (GC-MS) the efficiency of isolation of volatile compounds from five different Salvia L. (sage) species (S. lavandulifolia, S. staminea, S. hians, S. triloba, and S. nemorosa) by use of four different techniques [head-space extraction at 70 and 80°C, vapour distillation in a Deryng apparatus, and accelerated solvent extraction (ASE)]. We also compared the composition of the volatile fractions of these species collected during two different seasons (2007 and 2008). It was established that the composition of the volatile fractions is very dependent on the species considered and, in a much less pronounced way, on the growing season. This statement is valid irrespective of the technique used to isolate the volatile compounds from the plant matrix. The seasonal reproducibility of the compounds regarded as chemotaxonomic markers and chemotaxonomic advice compounds (and the repeated absence of such compounds from a species) makes the volatile fraction suitable for chemotaxonomic evaluation of sage. Finally, it was shown that head-space extraction of the volatile fraction at 70°C was the best extraction technique for the purpose of this study.

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Welcome to the Reader! You, the reader, hold in your hands a valuable journal issue that contains a number of thermal analysis papers that were presented at the 32nd annual meeting of the North American Thermal Analysis Society (NATAS). This conference was held in Williamsburg, Virginia, USA from the October 4 to 6, 2004. NATAS is known of its dedication in promoting the understanding and advancement of thermal analysis. NATAS is the largest national thermal analysis society in the world, and over its more than 30 year existence, it has represented the interests of numerous scientists, technicians and engineers, as well as major instrument vendors functioning in the area of thermal analysis. NATAS is an affiliate of the International Confederation for Thermal Analysis and Calorimetry (ICTAC), and has been co-operating with ASTM (American Society for Testing and Materials) for a long time especially Committee E37 on Thermal Measurements. The Short Course in Thermal Analysis held right before the conference, provide excellent educational opportunities for technical people, both experienced in the use of thermal analysis and those expanding their skills to learn thermal analysis. In this year's program, by our count, 225 papers were presented in nineteen different sessions (Kinetics; Fast Scan DSC; Semicrystalline Polymers; Thermal Conductivity; Pharmaceuticals; Poster Session; Educational Applications; Thermoplastic Polymers; Combined and Hyphenated Techniques; Composites, Nanocomposites and Thermosets; Thermal Hazards/Energetic Materials; Wood Materials; Rheology; Foods; Professional Enhancement; General Session; Flame Retardancy; Films and Fibers; Medical Polymers). Although thermal analysis is present in all areas of chemistry, the just described list of 2004 NATAS sessions clearly indicates that polymers still represent the majority among the materials tested by thermal analysis, or at least by the NATAS membership. Another phenomenon that may be seen when comparing these papers with earlier NATAS issues is some structural change in the type of the papers. As the chemical industry is inevitably being transformed in the era of globalization, it also affects thermal analysis. The emphasis is shifted from theoretical papers more to applications of thermal analysis. This special issue contains selected papers from the 2004 Annual NATAS Meeting. Another group of selected papers will be published in Thermochimica Acta. You may be surprised to see the NATAS material collected in two special issues of the two thermal analysis journals. However, NATAS has now decided it is time to return to the good old times and publish together the selected papers presented at its annual meeting. This year was a trial year of how the best NATAS papers should be presented to the world. The 2005 NATAS papers will be published in one special issue of Journal of Thermal Analysis and Calorimetry. At the annual NATAS meetings, in addition to the classical conference, there is always an instrument exhibition of a considerable size. The most important instrument manufacturers of the world are always present at this exhibition. In addition of being present, they provide funding to NATAS through financing some of the essential needs of the conference. Thus, we sincerely thank the following NATAS conference sponsors for their support: TA Instruments, PerkinElmer Life and Analytical Sciences and Mettler-Toledo. We are also thankful to both symposia sponsors: ExxonMobil Chemical Company and Abbott Laboratories. We hope the excellent relationship between NATAS and its corporate sponsors, and the instrument vendors is permanent. Above all, we thank all the authors and reviewers for their valuable contribution, because we feel that re-starting of regular publishing of the papers of the annual NATAS meetings is extremely important. We express our gratitude to the editorial offices of both Journal of Thermal Analysis and Calorimetry, and Thermochimica Acta for providing the opportunity to publish these papers.

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-Carretero , A. , Menéndez , J.A. , Menéndez-Gutiérrez , M.P. , … & Fernández-Gutiérrez , A. ( 2010 ): Qualitative screening of phenolic compounds in olive leaf extracts by hyphenated liquid chromatography and preliminary evaluation of cytotoxic activity

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Modulated Calorimetry Fire Science and Degradation Food Science General Poster Session General Session Honorary Session for Bruce Prime Hyphenated Thermal Analysis Isothermal Calorimetry/Microcalorimetry Kinetics Localized Thermal Analysis Nanocomposites

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., Rode, J., 1998: Determination of rutin in buckwheat leaves. Chromatography and Hyphenated Techniques. Bled. 153. Kim, J.S., Park, Y. J., Yang, M.H., Shim, J.W., 1994: Variation of rutin content in seed and plant of

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thermal contact is generally retained between the sample contained in the pan and the furnace. However, uncontrolled expansion can have a major influence on the optical-based hyphenated analytical techniques associated with the DSC. Therefore, a brief

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to get information on possible drug–excipient interactions. Therefore, the application of hyphenated techniques like TG/DTG/DTA/EGA/UATR is of great importance in solving pharmaceuticals problems such these mentioned before. The evaluation of

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