Authors:Bokka Ramesh, Vanka Uma Maheswara Sarma, Katragunta Kumar, Katragadda Suresh Babu, and Potturi Sita Devi
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.
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.
Authors:M. Sajewicz, J. Rzepa, M. Hajnos, Ł. Wojtal, D. Staszek, T. Kowalska, and M. Waksmundzka-Hajnos
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.
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
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
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.
Authors:H. Essafi, N. Trabelsi, C. Benincasa, A. Tamaalli, E. Perri, and M. Zarrouk
-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
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
., 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
Authors:S. A. Malik, L. Wang, M. A. Paget, F. Biddlestone, and G. F. Fernando
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
Authors:Corina Duda-Seiman, T. Vlase, Gabriela Vlase, D. Duda-Seiman, P. Albu, and N. Doca
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