Chemical Structure Identification by Differential Mass Spectra

2008 ◽  
pp. 221-233 ◽  
Author(s):  
Nicolae Dinca
Keyword(s):  
Mass Spectra ◽  
Chemical Structure ◽  
Structure Identification

Chemical Ionization Mass Spectrometry of Organophosphorus Insecticides

1974 ◽  
Vol 57 (5) ◽  
pp. 1050-1055 ◽  
Author(s):  
Roy L Holmstead ◽  
John E Casida
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Mass Spectra ◽  
Chemical Structure ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Organophosphorus Insecticides ◽  
Fragmentation Patterns

Abstract The chemical ionization (CI) mass spectra of 15 important organophosphorus insecticides and 14 of their major metabolites are discussed in relation to the effect of chemical structure on fragmentation patterns. The fragments obtained with CI are sometimes quite different from those formed on electron impact and, in general, simpler spectra are obtained with CI.

scholarly journals Linear Triquinane Sesquiterpenoids: Their Isolation, Structures, Biological Activities, and Chemical Synthesis

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2095 ◽  
Author(s):  
Yi Qiu ◽  
Wen-Jian Lan ◽  
Hou-Jin Li ◽  
Liu-Ping Chen
Keyword(s):  
Chemical Synthesis ◽  
Total Synthesis ◽  
Chemical Structure ◽  
Biological Activities ◽  
Structural Diversity ◽  
Structure Identification ◽  
Important Class ◽  
Soft Corals ◽  
Wide Range ◽  
New Challenges

Linear triquinane sesquiterpenoids represent an important class of natural products. Most of these compounds were isolated from fungi, sponges, and soft corals, and many of them displayed a wide range of biological activities. On account of their structural diversity and complexity, linear triquinane sesquiterpenoids present new challenges for chemical structure identification and total synthesis. 118 linear triquinane sesquiterpenoids were classified into 8 types, named types I–VIII, based on the carbon skeleton and the position of carbon substituents. Their isolation, structure elucidations, biological activities, and chemical synthesis were reviewed. This paper cited 102 articles from 1947 to 2018.

scholarly journals CHEMICAL STRUCTURE IDENTIFICATION IN METABOLOMICS: COMPUTATIONAL MODELING OF EXPERIMENTAL FEATURES

2013 ◽  
Vol 5 (6) ◽  
pp. e201302005 ◽  
Author(s):  
Lochana C. Menikarachchi ◽  
Mai A. Hamdalla ◽  
Dennis W. Hill ◽  
David F. Grant
Keyword(s):  
Computational Modeling ◽  
Chemical Structure ◽  
Structure Identification

Direct Analysis of Polymer Chemical Mixtures by Field Desorption Mass Spectroscopy

1980 ◽  
Vol 53 (1) ◽  
pp. 151-159 ◽  
Author(s):  
R. P. Lattimer ◽  
K. R. Welch
Keyword(s):  
Molecular Weight ◽  
Magnetic Resonance ◽  
Electron Impact ◽  
Mass Spectroscopy ◽  
Mass Spectra ◽  
Chemical Structure ◽  
Chemical Information ◽  
Spectroscopic Techniques ◽  
Field Desorption ◽  
Chemical Mixtures

Abstract Several examples have been given in which field desorption mass spectroscopy was very effective in the analysis of polymer chemical mixtures. The method has proved to be an excellent screening technique for initial examination of complex samples. Thus FD-MS data may be used as a basis for deciding whether further characterization by other spectroscopic or chromatographic techniques is necessary. In many cases, the FD molecular weights alone can quickly provide the data necessary for solution of a particular analytical problem. The fact that normally only one piece of data (the molecular ion) is provided for each component makes FD-MS unique in its ability to characterize polymer chemical mixtures. FD-MS is a very versatile tool that can be used in a number of practical applications of interest to the polymer chemist. On the negative side, it is evident that FD-MS by itself provides only limited chemical structure information. The molecular weight is provided and often nothing else. If this along with the history of the sample is not enough to deduce the structures present, then additional information must be obtained. Accurate mass measurements were used in several of the examples cited above. Isotope peaks for certain elements (e.g. S, Cl, Br) are often helpful, and electron impact (EI) and chemical ionization (CI) mass spectra may be obtained for the same samples. Other spectroscopic techniques (infrared and magnetic resonance) can be used to provide detailed structural information (e.g. isomerism and stereochemistry). Finally, chromatographic separations (GC, LC, GPC) may be necessary to isolate individual components for spectroscopic characterization. Field desorption may in some cases have other limitations that are not so obvious. The technique generally is not a good quantitative method although some promising work in this regard has appeared in the literature. The method is also compound selective; desorption rates and ionization efficiencies are quite dependent on molecular weight, volatility, chemical structure, and other factors. Certain types of highly polar compounds (underivatized carboxylic acids, for example) can be particularly troublesome. FD-MS operation at higher masses (MW > ∼ 2000) can be very difficult. Isomers which may be present are not distinguished since they have the same molecular weight. Finally, the method is not a “trace” technique in the modern sense of the word. Submicrogram quantities of pure materials can be examined, but for mixtures useful information may be lost for components present at levels less than ∼ 1–2% of the total. Nevertheless, we estimate that over 90% of the polymer chemical samples examined in our laboratory by field desorption have given good, readily interpretable FD mass spectra. Thus FD-MS has proven to be very effective tool for general characterization of these types of samples. The novel advantages of the method normally far outweigh its negative aspects and sometimes fickle reputation. Field desorption provides a very nice complement to structural data obtained by magnetic resonance, infrared, and electron impact mass spectroscopy. In most cases FD-MS can quickly provide chemical information on complex polymer chemical mixtures never before obtainable by any technique.

scholarly journals Computer-Assisted Structure Identification of Unknown Mass Spectra

1977 ◽  
pp. 1-17 ◽  
Author(s):  
R. VENKATARAGHAVAN ◽  
H. E. DAYRINGER ◽  
G. M. PESYNA ◽  
B. L. ATWATER ◽  
I. K. MUN ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Structure Identification ◽  
Computer Assisted

scholarly journals 2′-Hydroxylated 3-Deoxyanthocyanin from the Flowers of Cosmos sulphureus Cultivars

2019 ◽  
Vol 14 (9) ◽  
pp. 1934578X1987621
Author(s):  
Tsukasa Iwashina ◽  
Kotarou Amamiya ◽  
Tsunashi Kamo ◽  
Junichi Kitajima ◽  
Takayuki Mizuno ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Magnetic Resonance ◽  
High Performance ◽  
Mass Spectra ◽  
Chemical Structure ◽  
Resonance Spectroscopy ◽  
Spectroscopic Methods ◽  
Liquid Chromatograph

A new 3-deoxyanthocyanin was isolated from the orange flowers of Cosmos sulphureus cultivar “Diabolo,” together with known aurone, chalcone, flavone, flavonol, and flavanone. The chemical structure of 3-deoxyanthocyanin was established as 5,7,2′,4′-tetrahydroxyflavylium 4′- O-β-d-glucopyranoside by chemical and spectroscopic methods including UV, FAB MS, and 1H and 13C nuclear magnetic resonance spectroscopy (NMR), and named as cosmonidin 4′- O-glucoside (1a). Other known flavonoids were characterized as sulfuretin 6- O-glucoside (2), butein 4′- O-glucoside (3), quercetin 3- O-glucoside (4), luteolin 7- O-glucuronide (5), and eriodictyol 7- O-glucuronide (6) by UV, liquid chromatograph - mass spectra (LC-MS), NMR, and high performance liquid chromatography comparisons with authentic samples. Anthocyanin, which 2′-position is hydroxylated, has not been reported until now. Compound (1a) was also found in other 10 C. sulphureus cultivars “Lamala Lemon,” “Sunrise,” “Dwarf Yellow,” “Cosmic Yellow,” “Carpet Gold,” “Mandarin,” “Cosmic Orange,” “Orange Flare,” “Cosmic Red,” and “Sunset.”

High-Throughput Non-targeted Chemical Structure Identification Using Gas-Phase Infrared Spectra

2021 ◽  
Author(s):  
Erandika Karunaratne ◽  
Dennis W. Hill ◽  
Philipp Pracht ◽  
José A. Gascón ◽  
Stefan Grimme ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Throughput ◽  
Infrared Spectra ◽  
Chemical Structure ◽  
Structure Identification

Computer-assisted prediction of the classification of the pesticide chemical structure in mass spectra

2007 ◽  
Vol 35 (10) ◽  
pp. 1449-1454 ◽  
Author(s):  
Yu-Xi Zhang ◽  
Qing Xiong ◽  
Gang Yang ◽  
Meng-Long Li
Keyword(s):  
Mass Spectra ◽  
Chemical Structure ◽  
Computer Assisted ◽  
Pesticide Chemical

A computer search system for chemical structure elucidation based on low-resolution mass spectra

1981 ◽  
Vol 133 (4) ◽  
pp. 517-525 ◽  
Author(s):  
K.S. Lebedev ◽  
V.M. Tormyshev ◽  
B.G. Derendyaev ◽  
V.A. Koptyug
Keyword(s):  
Structure Elucidation ◽  
Mass Spectra ◽  
Chemical Structure ◽  
Computer Search ◽  
Low Resolution ◽  
Search System ◽  
Resolution Mass
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