scholarly journals Identification of unknown compound extracted from the hair of exhumed human remains using mass spectrometric and gas chromatographic data

2021 ◽  
Vol 25 (1) ◽  
pp. 34-42
Author(s):  
Sergei A. Savchuk ◽  
◽  
Igor G. Zenkevich ◽  
Keyword(s):  
Stationary Phases ◽  
Toxic Substances ◽  
Polydimethyl Siloxane ◽  
Unknown Compound ◽  
Original Algorithm ◽  
Pharmaceutical Application ◽  
Tautomeric Forms ◽  
Structural Analogues ◽  
Molecular Masses ◽  
Index Value

The real example of GC-MS identification of unknown constituent of human hair extract belonging to the exhumed remains is considered. The identification of this constituent (molecular weight 238 Da) was unsuccessful using both its standard mass spectrum (electron ionization) in combination with lib­ra­ry search, and its GC retention index value (~1540 on semi-standard non-polar polydimethyl siloxane stationary phases with 5% phenyl groups). However, its identification appea­red to be possible using the original algorithm of data processing. This approach implies revealing the structural analogues of unknown analytes, primarily their homologues which differ by molecular masses on ± 14 Da and by composition on CH2 homolo­go­us difference. This approach allowed revealing such analogues of unknown analyte as Flavesone (2,2,4,4-tetramethyl-2-isobutyrylcyclohexa-1,3,5-trione), Leptospermone (2,2,4,4-tetramethyl-2-isopentanoylcyclohexa-1,3,5-trione), and some others. All these compounds belong to a rather “exotic” class of natural compounds knows as cyclic b-triketones. Based on the obtained data, the possible structure of the constitu­ent under the consideration was proposed as 2,2,4,4-tetramethyl-2-propionylcyclohexa-1,3,5-trione. The principal fea­ture of cyclic b-triketones is their existence in a few tautomeric forms. Another tautomer of triketone under discussion is 5-hydroxy-2,2,6,6-tetramethyl-4-propionyl-4-en-1,3-dio­ne (CAS № 87552-01-0). This compound is found to be the constituent of Leptosper­mum scoparium essential oil and some other plants, and it belongs to the group of structural analogues of Flave­sone. The most known pharmaceutical application of essential oils containing these compounds are the components of conditioners for hair and skin. The results confirm this formerly un­known component does not belong to the group of toxic substances. This excludes the criminal origin of the remains.

Development of a bio-monitoring system for toxicants in water with fish

2001 ◽  
Vol 1 (2) ◽  
pp. 9-17
Author(s):  
Y.-H. Lee ◽  
H.-K. Lee ◽  
C.-H. Chang ◽  
W.-H. Kim
Keyword(s):  
Monitoring System ◽  
Treatment Plant ◽  
Ccd Camera ◽  
Water Treatment Plant ◽  
Abnormal Behavior ◽  
Time Interval ◽  
Toxic Substances ◽  
Bio Monitoring ◽  
Index Value ◽  
A Charge

A bio-monitoring system for toxicants in water has been developed and verified for actual applications. This system is based on the motionality of five Acheilognathus lanceolata, a fish known to be very sensitive to toxic substances, moving around in an aquarium. Their movements are continuously monitored with a charge coupled device (CCD) camera and analyzed to find and quantify any abnormal behavior in their motional characteristics in comparison with the pre-acquired data. That is, the images of fish captured by a CCD camera are digitalized to identify the location of fish in a constant time interval and the locations of each fish were then analyzed mathematically with a personal computer using the equations proposed to determine the motional characteristics such as floatness, fledness and mobility(agility). These data are then converted by means of fuzzy estimation to an index value, defined as the contamination index (CI), by which the system provides the information about the overall toxic strength of the toxicant in the water flowing into the aquarium. If the fish are exposed to toxicant(s), the CI value will be proportional to the strength of its toxicity. The pilot test was performed in a water treatment plant for six months in order to verify the reproducibility of the system over the unstable conditions such as highly turbid water after rainfall as well as in normal conditions. The test results revealed that this monitoring system has good reproducibility and sensitivity, proving our approach, described in this paper, is reliable. As a result, this approach seems to enable us to make a quick and easy detection of toxic substances contained in water, therefore, this system can be applied to a source of water supply as a toxicant watching system.

Separation of Fatty Acid Dimethyl Esters on an Ionic Liquid Gas Chromatographic Column

2020 ◽  
Author(s):  
R E Pauls ◽  
B Pease
Keyword(s):  
Ionic Liquid ◽  
Fatty Acid ◽  
Stationary Phases ◽  
Carbon Number ◽  
Fatty Acid Esters ◽  
Reaction Products ◽  
Isomer Separation ◽  
Metathesis Reaction ◽  
Polydimethyl Siloxane ◽  
Acid Esters

Abstract An ionic liquid (IL) 111 column was compared with other commonly employed stationary phases including polydimethyl siloxane and polyethylene glycol for the separation of fatty acid monomethyl and dimethyl esters. The fatty acid esters employed in this study were derived from metathesis reactions of vegetable oils both with and without olefins. The IL 111 column demonstrated enhanced performance compared with conventional columns for the separation of these esters. These advantages included significantly enhanced retention of dimethyl esters relative to monomethyl esters, excellent cis/trans isomer separation and the ability to analyze higher carbon number dimethyl esters. As a result, these columns are highly suited for the analysis of mixtures of mono- and dimethyl fatty acid esters found in lipid metathesis reaction products or to determine monofunctional impurities in samples of commercial dimethyl esters.

Selectivity-column temperature relationship as a new strategy in predicting separation of structural analogues in HPLC by using different stationary phases

RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62686-62696 ◽  
Author(s):  
Shu-ying Han ◽  
Hui-min Yu ◽  
Yu-qiong Pei ◽  
Yu-mei Chi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Stationary Phases ◽  
Column Temperature ◽  
Structural Analogues ◽  
New Strategy ◽  
Hoff Equation ◽  
Relationship Of ◽  
As Relationship

The effect of changes in column temperature on van't Hoff equation, as well as relationship of separation and column temperature in high performance liquid chromatography (HPLC) by using different stationary phases, have been discussed and compared.

scholarly journals SVM Prediction Model Interface for Plant Contaminates

2021 ◽  
Vol 38 (4) ◽  
pp. 1023-1032
Author(s):  
Shilpi Aggarwal ◽  
Madhulika Bhatia ◽  
Rosy Madaan ◽  
Hari Mohan Pandey
Keyword(s):  
Pollution Index ◽  
Classification Model ◽  
Toxic Substances ◽  
Threshold Values ◽  
The Earth ◽  
Life Threatening ◽  
Chlorophytum Comosum ◽  
Ocimum Tenuiflorum ◽  
Rgb Images ◽  
Index Value

In today's time, our nature is fighting against many life-threatening problems which can even threaten the existence of life on the Earth. Pollution is one of the deadliest problems among them. It is caused primarily by means of air, water and land but air pollution is the most severe and dreadful among them. It is caused by introduction of toxic substances like oxides of Sulphur, nitrogen and carbon into the atmosphere making it unfit for living beings. Along with humans, plants have also become a victim to it, and this fact is mostly ignored. A model has been designed to predict the effect of pollution on plants. Image samples of 5 Indian oxygen rich plants namely Ocimum Tenuiflorum, Sansevieria Trifasciata, Chlorophytum Comosum, and Azadirachta Indica have been taken for analysis and various properties like shape, color, corners and texture of the plants were considered from these input RGB images. As a consequence of these properties and the pollution index value, certain calculations have been performed and the results are compared with the threshold values. Based on the range in which the calculated results lie, the plants will be categorized into a category which depicts the severity level of pollution in the environment. After applying the model on the images, a dataset was prepared and SVM classification model has been trained on it which predict with an accuracy of 85%. It has been presented in the form of an interactive user interface to predict the effect of pollution on plants. Plants are an integral part of nature and should not be ignored.

scholarly journals Determination of molecular masses for petroleum distillates by simualted distillation

2012 ◽  
Vol 4 (5) ◽  
pp. 43-55 ◽  
Author(s):  
Lante Carbognani
Keyword(s):  
Stationary Phases ◽  
Size Exclusion ◽  
Chromatographic Separations ◽  
Calibration Standards ◽  
Hydrocarbon Group ◽  
Simulated Distillation ◽  
Size Exclusion Chromatographic ◽  
Petroleum Distillates ◽  
Molecular Masses

Determination of Molecular Mass (MM) for petroleum distillates is explored for selected samples viaHigh Temperature Simulated Distillation (HTSD). MM is determined as a by-product from routineHTSD carried out using open wall capillary columns coated with apolar stationary phases. No samplepre-separation into hydrocarbon group-types is required. Determined MM values were validated with resultsachieved via correlations based on specific gravity and refractive index. Furthermore, determined MM withthe former methodologies were found to match mass spectrometric determinations carried out for the basicpolar components present within the studied samples. Moreover, HTSD analyzed petroleum distillates areproposed as more representative calibration standards for size exclusion chromatographic separations, thusopening the feasibility of extrapolating MM determination for non volatile petroleum residua.

Enantioseparation characteristics of tadalafil and its intermediate on chitin derived chiral stationary phases

The Analyst ◽  
2015 ◽  
Vol 140 (16) ◽  
pp. 5593-5600 ◽  
Author(s):  
Juan Zhang ◽  
Zhao-Qun Wang ◽  
Xiao-Chen Wang ◽  
Jun-Jun Zhang ◽  
Zheng-Wu Bai ◽  
...  
Keyword(s):  
Stationary Phases ◽  
Chiral Stationary Phases ◽  
Structural Analogues

The enantioseparation of tadalafil and its intermediate was affected by the presence of their diastereoisomers or structural analogues.

Quantitative analysis by reconstruction of HREM focal series

1994 ◽  
Vol 52 ◽  
pp. 740-741
Author(s):  
W. Coene ◽  
A. Thust ◽  
M. Op de Beeck ◽  
D. Van Dyck
Keyword(s):  
Phase Retrieval ◽  
Image Plane ◽  
Initial Guess ◽  
Recursive Least Squares ◽  
Objective Lens ◽  
Electron Wave ◽  
Electron Sources ◽  
Original Algorithm ◽  
Coherent Field ◽  
Direct Interpretation

Compared to conventional electron sources, the use of a highly coherent field-emission gun (FEG) in TEM improves the information resolution considerably. A direct interpretation of this extra information, however, is hampered since amplitude and phase of the electron wave are scrambled in a complicated way upon transfer from the specimen exit plane through the objective lens towards the image plane. In order to make the additional high-resolution information interpretable, a phase retrieval procedure is applied, which yields the aberration-corrected electron wave from a focal series of HRTEM images (Coene et al, 1992).Kirkland (1984) tackled non-linear image reconstruction using a recursive least-squares formalism in which the electron wave is modified stepwise towards the solution which optimally matches the contrast features in the experimental through-focus series. The original algorithm suffers from two major drawbacks : first, the result depends strongly on the quality of the initial guess of the first step, second, the processing time is impractically high.

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