scholarly journals Characterization of Arabica and Robusta Coffees by Ion Mobility Sum Spectrum

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3123 ◽  
Author(s):  
Paweł Piotr Konieczka ◽  
María José Aliaño-González ◽  
Marta Ferreiro-González ◽  
Gerardo F. Barbero ◽  
Miguel Palma
Keyword(s):  
Ion Mobility ◽  
Good Alternative ◽  
Linear Discrimination ◽  
Lack Of Information ◽  
Novel Approach ◽  
Concentration Step ◽  
Total Volatile Organic Compounds ◽  
Traditional Approaches ◽  
Preparation Techniques

Aroma is one of the main characteristics of coffee specimens. Different mixtures of Arabica and Robusta coffees are usually found in the market to offer specific aroma or flavor profiles to consumers. However, the mixed samples or their proportions are not always identified in the product labels. Since the price of Arabica is much higher than that of Robusta, this lack of information is not only an economical issue but a possible fraud to consumers, besides the potential allergic reaction that these mixtures may trigger in some individuals. In this paper, two sample preparation techniques were compared before the analysis of the total volatile organic compounds (VOCs) found in Robusta, Arabica, and in the mixture from both coffee types. The comparison of the signals obtained from the analyses showed that the VOCs concentration levels obtained from the headspace (HS) analyses were clearly higher than those obtained from the pre-concentration step where an adsorbent, an active charcoal strip (ACS + HS), was used. In the second part of this study, the possibility of using the headspace gas-chromatography ion mobility spectrometry (HS-GC-IMS) for the discrimination between Arabica, Robusta, and mixed coffee samples (n = 30) was evaluated. The ion mobility sum spectrum (IMSS) obtained from the analysis of the HS was used in combination with pattern recognition techniques, namely linear discrimination analysis (LDA), as an electronic nose. The identification of individual compounds was not carried out since chromatographic information was not used. This novel approach allowed the correct discrimination (100%) of all of the samples. A characteristic fingerprint for each type of coffee for a fast and easy identification was also developed. In addition, the developed method is ecofriendly, so it is a good alternative to traditional approaches.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

scholarly journals Application of Innovative TGA/Chemometric Approach for Forensic Purposes: The Estimation of the Time since Death in Contaminated Specimens

Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 121
Author(s):  
Roberta Risoluti ◽  
Giuseppina Gullifa ◽  
Vittorio Fineschi ◽  
Paola Frati ◽  
Stefano Materazzi
Keyword(s):  
Multidisciplinary Approach ◽  
Vitreous Humor ◽  
Classification Model ◽  
Forensic Sciences ◽  
Time Since Death ◽  
Time Of Death ◽  
Novel Approach ◽  
Chemometric Approach ◽  
Postmortem Examinations

Chronothanatology has always been a challenge in forensic sciences. Therefore, the importance of a multidisciplinary approach for the characterization of matrices (organs, tissues, or fluids) that respond linearly to the postmortem interval (PMI) is emerging increasingly. The vitreous humor is particularly suitable for studies aimed at assessing time-related modifications because it is topographically isolated and well-protected. In this work, a novel approach based on thermogravimetry and chemometrics was used to estimate the time since death in the vitreous humor and to collect a databank of samples derived from postmortem examinations after medico–legal evaluation. In this study, contaminated and uncontaminated specimens with tissue fragments were included in order to develop a classification model to predict time of death based on partial least squares discriminant analysis (PLS-DA) that was as robust as possible. Results demonstrate the possibility to correctly predict the PMI even in contaminated samples, with an accuracy not lower than 70%. In addition, the correlation coefficient of the measured versus predicted outcomes was found to be 0.9978, confirming the ability of the model to extend its feasibility even to such situations involving contaminated vitreous humor.

scholarly journals Synthesis and Biological Activity of New Brassinosteroid Analogs of Type 24-Nor-5β-Cholane and 23-Benzoate Function in the Side Chain

2021 ◽  
Vol 22 (9) ◽  
pp. 4808
Author(s):  
Nitza Soto ◽  
Karoll Ferrer ◽  
Katy Díaz ◽  
César González ◽  
Lautaro Taborga ◽  
...  
Keyword(s):  
Good Alternative ◽  
Positive Control ◽  
Starting Material ◽  
Chemical Structures ◽  
High Reaction ◽  
Similar Chemical ◽  
Synthetic Procedure ◽  
Hyodeoxycholic Acid ◽  
External Stresses

Brassinosteroids are polyhydroxysteroids that are involved in different plants’ biological functions, such as growth, development and resistance to biotic and external stresses. Because of its low abundance in plants, much effort has been dedicated to the synthesis and characterization of brassinosteroids analogs. Herein, we report the synthesis of brassinosteroid 24-nor-5β-cholane type analogs with 23-benzoate function and 22,23-benzoate groups. The synthesis was accomplished with high reaction yields in a four-step synthesis route and using hyodeoxycholic acid as starting material. All synthesized analogs were tested using the rice lamina inclination test to assess their growth-promoting activity and compare it with those obtained for brassinolide, which was used as a positive control. The results indicate that the diasteroisomeric mixture of monobenzoylated derivatives exhibit the highest activity at the lowest tested concentrations (1 × 10−8 and 1 × 10−7 M), being even more active than brassinolide. Therefore, a simple synthetic procedure with high reaction yields that use a very accessible starting material provides brassinosteroid synthetic analogs with promising effects on plant growth. This exploratory study suggests that brassinosteroid analogs with similar chemical structures could be a good alternative to natural brassinosteroids.

scholarly journals Ion Mobility–Mass Spectrometry for Bioanalysis

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 33
Author(s):  
Xavier Garcia ◽  
Maria del Mar Sabaté ◽  
Jorge Aubets ◽  
Josep Maria Jansat ◽  
Sonia Sentellas
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Biological Samples ◽  
Ion Mobility Mass Spectrometry ◽  
Exogenous Compounds ◽  
Analytical Separation

This paper aims to cover the main strategies based on ion mobility spectrometry (IMS) for the analysis of biological samples. The determination of endogenous and exogenous compounds in such samples is important for the understanding of the health status of individuals. For this reason, the development of new approaches that can be complementary to the ones already established (mainly based on liquid chromatography coupled to mass spectrometry) is welcomed. In this regard, ion mobility spectrometry has appeared in the analytical scenario as a powerful technique for the separation and characterization of compounds based on their mobility. IMS has been used in several areas taking advantage of its orthogonality with other analytical separation techniques, such as liquid chromatography, gas chromatography, capillary electrophoresis, or supercritical fluid chromatography. Bioanalysis is not one of the areas where IMS has been more extensively applied. However, over the last years, the interest in using this approach for the analysis of biological samples has clearly increased. This paper introduces the reader to the principles controlling the separation in IMS and reviews recent applications using this technique in the field of bioanalysis.

3D crustal-scale structure of the West Iberia margin: a novel approach to integrated structural characterization of passive margins

2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Cristina Granado ◽  
Alfonso Muñoz-Martín ◽  
Antonio J. Olaiz ◽  
Oscar Fernández ◽  
María Druet
Keyword(s):  
Structural Characterization ◽  
Scale Structure ◽  
The West ◽  
Passive Margins ◽  
Novel Approach

scholarly journals In vitro cytotoxicity of Aspilia pluriseta Schweinf. extract fractions

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sospeter N. Njeru ◽  
Jackson M. Muema
Keyword(s):  
Biological Activities ◽  
Vero Cells ◽  
In Vitro Cytotoxicity ◽  
Root Extract ◽  
Lack Of Information ◽  
Information Gap ◽  
Diphenyltetrazolium Bromide ◽  
Potential Use

Abstract Objectives We and others have shown that Aspilia pluriseta is associated with various biological activities. However, there is a lack of information on its cytotoxicity. This has created an information gap about the safety of A. pluriseta extracts. As an extension to our recent publication on the antimicrobial activity and the phytochemical characterization of A. pluriseta root extracts, here we report on cytotoxicity of tested solvent fractions. We evaluated the potential cytotoxicity of these root extract fractions on Vero cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results We show that all solvent extract fractions (except methanolic solvent fractions) had cytotoxic concentration values that killed 50% of the Vero cells (CC50) greater than 20 µg/mL and selectivity index (SI) greater than 1.0. Taken together, we demonstrate that, A. pluriseta extract fractions’ earlier reported bioactivities are within the acceptable cytotoxicity and selective index limits. This finding scientifically validates the potential use of A. pluriseta in the discovery of safe therapeutics agents.

scholarly journals Generation and characterization of antibodies specific for caspase-cleaved neo-epitopes: a novel approach

2011 ◽  
Vol 2 (9) ◽  
pp. e205-e205 ◽  
Author(s):  
X Ai ◽  
B Butts ◽  
K Vora ◽  
W Li ◽  
C Tache-Talmadge ◽  
...  
Keyword(s):  
Novel Approach
Sign in / Sign up

Export Citation Format

Share Document