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Wyszukujesz frazę "MALDI MS" wg kryterium: Temat


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Tytuł:
Maldi – metoda do zastosowań w analizie strukturalnej polimerów
Maldi – method for use in structural analysis of polymers
Autorzy:
Swinarew, B.
Swinarew, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/171598.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
polimery
spektrometria mas z jonizacją laserową wspomaganą matrycą
MALDI-TOF
kopolimery
degradacja polimeru
polymers
matrix-assisted laser desorption ionization mass spectrometry
MALDI-TOF MS
copolymers
polymer degradation
Opis:
Polymers as one of the fastest growing groups of widespread use of synthetic materials are characterized by a great diversity of structures. Structural characterization of polymers generally includes: an assessment of the average molecular weight (Mn) and the molar mass distribution (PD) to determine the structure of repeating units (mers) sequence analysis of the copolymer, identification of the end groups, the detection and identification of contaminants and substances present in the composition of the polymer asa dopant. Modern mass spectrometry (MS) offers the opportunity to study the smallest structural details of macromolecular materials [1–10]. Because of the variety of potential structures of polymer analysis process is to answer a few questions by a certain pattern. The first step is to determine the chemical structure of the polymer backbone. The second step is to identify whether the chains have branching points and define the degree of branching. The third important step is to correct end groups identification, also for the detection of cyclic oligomers that can be present. The structural studies can be made by mass spectrometer using reflectron mode. In the essence, the method involves three steps. The first analysis is performed with standard mass spectrum of the sample. Then the precursor ion (parent ion) is selected, which is subjected to further analysis by MS changed voltages and reflectron mode. This paper aims to present the issues related to the detailed analysis and characterization of polymeric materials produced on a large scale. Before, for materials such as poly(propylene), poly(ethylene), poly(styrene), polycarbonate, etc., increasing demands on the mechanical and technological parameters were placed. Maintaining a high level of products is associated with a very rigorous process control of the manufacturing, processing and transportation at every stage. The optimal tool for the structural characteristics of these polymeric materials is the defense technique MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time- -Of-Flight Mass Spectrometer) due to its versatility, speed and extremely high precision. Below, we present some aspects of MALDI MS analysis of polymeric materials and composites. Note, that the following literature review focuses on the recent developments in the field of preparation of the samples, to achieve high mass resolution, the identification of polymers and copolymers, the accuracy of the molar mass determination and the identification of functional end groups, sequence analysis of the copolymer.
Źródło:
Wiadomości Chemiczne; 2014, 68, 7-8; 645-660
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prekatalizatory oligomeryzacji olefin oparte na kationach chromu(III) oraz kobaltu(II) : właściwości fizykochemiczne oraz katalityczne
Precatalysts for olefin oligomerization based on chromium(III) and cobalt(II) cations : physicochemical and catalytic properties
Autorzy:
Malinowski, Jacek
Drzeżdżon, Joanna
Sikorski, Artur
Jacewicz, Dagmara Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/2200439.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
kation chromu(III)
oligomeryzacja olefin
2-chloro-2-propen-1-ol
aktywność katalityczna
MALDI-TOF MS
chromium(III)
olefin oligomerization
catalytic activity
Opis:
The introduction describes the most important facts about the development of polyolefins. This is followed by a description of the role of polyolefins and the most important applications in industry and everyday life. The paper presents new, highly active precatalysts for oligomerization of olefins. These are coordination compounds based on chromium(III) cation, anions of various polycarboxylic acids and auxiliary ligands, such as 1,10-phenanthroline or 2,2'-bipyridyl. This review presents their crystallographic structures and basic parameters describing the elementary cell. The catalytic properties of the obtained oligomerization products using chromium(III) coordination compounds by MALDI-TOF MS are described. In conclusion, the presented precatalysts are compared with others described in the literature.
Źródło:
Wiadomości Chemiczne; 2022, 76, 11-12; 943--962
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
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