Identification of Rubber Additives by Field Desorption and Fast Atom Bombardment Mass Spectroscopy

1984 ◽  
Vol 57 (5) ◽  
pp. 1013-1022 ◽  
Author(s):  
Robert P. Lattimer ◽  
Robert E. Harris ◽  
Doyle B. Ross ◽  
Hugh E. Diem
Keyword(s):  
Molecular Weight ◽  
Mass Range ◽  
Molecular Ions ◽  
Organic Additives ◽  
Compound Identification ◽  
Mass Spectral ◽  
Rubber Compounds ◽  
General Answer ◽  
Background Ions ◽  
Normal Background

Abstract From the results presented here, it is clear that FD-MS and FAB-MS are very effective analytical methods for the identification of organic additives in extracts from rubber compounds. In the examples above, the molecular weight information provided by FD and FAB provided a nice complement to the IR data. In cases where IR could give only a general answer (i.e., a compound class), the mass spectral data provided a very specific compound identification. It is encouraging that all the samples examined gave useful spectra by both FD and FAB analysis. In most cases, the same information was obtained by both techniques. Certain compounds, however, were observed by FD but not by FAB (wax, oil, isocyanurate antioxidant). While FD provided only molecular weight information, FAB also provided fragmentation to aid in the confirmation of component assignments. Both the FD and FAB mass spectra were fairly complex for most of the extracts, but for different reasons. In FD, oil and wax oligomers gave many molecular ions over a wide mass range. FAB spectra, on the other hand, were somewhat cluttered due to the normal background ions produced by the sputtering process. With both techniques, however, the various components in some fairly complex mixtures were readily identified.

Tandem Mass Spectrometry (MS/MS) for Analysis of Additives in a Rubber Vulcanizate

1988 ◽  
Vol 61 (4) ◽  
pp. 658-668 ◽  
Author(s):  
Robert P. Lattimer
Keyword(s):  
Neutral Loss ◽  
Direct Analysis ◽  
Organic Additive ◽  
Organic Additives ◽  
Mass Measurements ◽  
Chemical Noise ◽  
Mass Spectral ◽  
Rubber Compounds ◽  
Ionization Methods

Abstract MS/MS appears to have considerable potential as a means for improved direct mass spectral characterization of organic additives in rubber compounds. In this report, we have shown how daughter-ion, parent-ion, and neutral-loss scans can improve the specificity for identification of organic additive components in rubber vulcanizates. The use of MS/MS to reduce the “chemical noise” in the direct analysis of complex mixtures is demonstrated. MS/MS should not be viewed as a technique that will replace other mass spectral methods in rubber applications. For example, desorption ionization methods, GC/MS, LC/MS and high-resolution mass measurements will still have important roles. MS/MS can serve as a supplemental tool for direct mixture analysis that is both rapid and powerful.

Identification of Organic Components in Uncured Rubber Compounds Using Mass Spectrometry

1988 ◽  
Vol 61 (4) ◽  
pp. 639-657 ◽  
Author(s):  
R. P. Lattimer ◽  
R. E. Harris ◽  
C. K. Rhee ◽  
H-R. Schulten
Keyword(s):  
Mass Spectrometry ◽  
Organic Additive ◽  
Molecular Ions ◽  
Organic Additives ◽  
Additional Information ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Surface Desorption ◽  
Direct Thermal Desorption ◽  
Ionization Methods

Abstract Three carbon-black-filled rubber compounds of known composition were analyzed by mass spectrometry. Direct thermal desorption was used with three different methods of ionization (EI, CI, FI). In addition, the three rubbers were examined by FAB-MS (without liquid matrix) as a means for surface desorption/ionization. Extracts of the rubbers were also examined using two different solvents (acetone and acetonitrile). Each extract was examined directly by five methods of ionization (EI, CI, FI, FD, FAB). Of the various vaporization/ionization methods, it appears that FI/FD is the most efficient for identifying typical organic additives in rubber stocks. The analysis can be carried out using either the untreated rubber (FI mode) or else a solvent extract (FD mode). Molecular ions are dominant, which facilitates the characterization of the complex organic additive mixtures that are present in typical compounded rubbers. For samples in which the identity of FD/FI molecular ions is unclear, further analysis using other methods (EI, CI, FAB, MS/MS, GC/MS, LC/MS, high resolution) can be carried out to gain additional information. We conclude that FD and FI yield the most useful information in the shortest period of time. The main difference between the results of this study and those of the volcanizate study is with respect to the curatives. Intact accelerator molecules could readily be observed in the spectra from the uncured stocks, while only accelerator fragments could be observed from the vulcanizates.

A New Look at Direct Compound Analysis Using Pyrolysis Mass Spectrometry

1983 ◽  
Vol 56 (5) ◽  
pp. 1031-1044 ◽  
Author(s):  
Jerry B. Pausch ◽  
Robert P. Lattimer ◽  
Henk L. C. Meuzklaar
Keyword(s):  
Mass Spectrometry ◽  
Mass Range ◽  
Molecular Ions ◽  
Volatile Components ◽  
Pyrolysis Mass Spectrometry ◽  
Organic Additives ◽  
Single Experiment ◽  
Pattern Recognition Techniques ◽  
Temperature Programmed ◽  
Future Work

Abstract For direct compound analysis, pyrolysis mass spectrometry offers renewed hope that the time-consuming and costly separations currently required can be bypassed, at least in part. Polymer blends and copolymers are readily identified along with certain additives. The ability to achieve this information quickly from a single experiment is a valuable improvement. However, more work needs to be done to identify curatives, oils, and higher molecular weight rubber chemicals in compounds. For example, the mass range scanned needs to be expanded to detect higher molecular ions. Temperature-programmed Py-MS may prove useful in separating the more volatile components (nonpolymeric oils and organic additives) for easier detection. Future work will also assess the quantitative potential of the technique. The success with experiments on CPVC materials using pattern recognition techniques opens up a new dimension for compound analysis. Besides being able to determine composition, selected information about reaction mechanisms, morphology, physical properties, or other important parameters may now be possible.

THERMOPHYSICAL AND DYNAMIC PROPERTIES OF BUTADIENE-NITRILE RUBBER FILLED WITH ULTRA HIGH-MOLECULAR WEIGHT POLYETHYLENE

2021 ◽  
Vol 0 (2) ◽  
pp. 36-43
Author(s):  
N.V. Shadrinov ◽  
◽  
A.A. Khristoforova ◽  
Keyword(s):  
Molecular Weight ◽  
Dynamic Properties ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Physicomechanical Properties ◽  
Butadiene Rubber ◽  
Rubber Compounds ◽  
Ultrahigh Molecular Weight ◽  
Before And After ◽  
Butadiene Nitrile Rubber ◽  
Ultra High Molecular Weight

The results of the study of the complex of properties of an elastomeric composite material based on nitrile butadiene rubber BNKS-18 and ultrahigh molecular weight polyethylene are presented. The effect of UHMWPE on the vulcanization characteristics of rubber compounds, the physicomechanical properties of vulcanizates before and after thermal aging in a hydrocarbon environment and air, and also on the dynamic properties before and after curing are investigated.

scholarly journals Antimicrobial, Antifertility and Antiinflammatory Approach to Tetradentate Macrocyclic Complexes of Iron(II) and Manganese(II)

2002 ◽  
Vol 8 (6) ◽  
pp. 347-353 ◽  
Author(s):  
Ashu Chaudhary ◽  
D. P. Jaroli ◽  
R. V. Singh
Keyword(s):  
Molecular Weight ◽  
Reproductive Organs ◽  
Spectral Studies ◽  
Central Metal Atom ◽  
Central Metal ◽  
Testicular Sperm ◽  
Mass Spectral ◽  
Sperm Density ◽  
Elemental Analyses

Some antifertility inhibitors of 18 to 24-membered tetraazamacrocyclic complexes of iron(II) and manganese(II) have been synthesised by the template condensation using 1,3-phenylenediamine with malonic acid, succinic acid, glutaric acid and adipic acid. The reaction proceed smoothly to completion. The complexes were characterized by elemental analyses, molecular weight determinations, infrared, electronic, magnetic moment, mössbaur and mass spectral studies. The elemental analyses are consistent with the formation of the complexes [M(N4Ln)Cl2] (M = Fe(lI) or Mn(II)). All these complexes are stable and monomeric in nature as indicated by the molecular weight determinations. The spectral studies confirm the octahedral geometry around the central metal atom. The complexes have been screened in vitro against a number of fungi and bacteria to assess their growth inhibiting potential. The testicular sperm density and testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trials and biochemical parameters of reproductive organs have been examined and discussed.

scholarly journals ZONE FOR COLLECTING THE IONS OF A GIVEN MASS RANGE IN THE PLASMA FILTER OF MASSES

2020 ◽  
pp. 185-190
Author(s):  
V.V. Katrechko ◽  
V.B. Yuferov ◽  
V.O. Ilichova ◽  
A.S. Svichkar ◽  
S.N. Khizhnyak
Keyword(s):  
Cyclotron Frequency ◽  
Initial Conditions ◽  
Radial Electric Field ◽  
Plasma Source ◽  
Mass Range ◽  
Molecular Ions ◽  
Variable Component ◽  
Mass Filter ◽  
Ion Motion ◽  
Ion Trajectory

The trajectories of motion for atomic and molecular ions of a given mass range (M = 232...277) in the plasma mass filter, which is currently being developed, are calculated. The influence of the initial conditions (energy, angle, radius) on the ion trajectory to determine the dimensions of the collector for actinides, the so-called “pocket”, is studied. It is shown that the variable component of the radial electric field, tuned to a frequency equal to half the ion cyclotron frequency for M = 238 allows target ions to enter the “pocket”. An analysis of the calculations showed that there are limitations on energy, angle, and radius related to the initial conditions for the ion motion, that must be taken into account when creating the plasma source for the plasma mass filter.

Molecular Structure and Macroscopic Properties of Synthetic Cis-Poly(Isoprene)

1974 ◽  
Vol 47 (2) ◽  
pp. 342-356 ◽  
Author(s):  
V. A. Grechanovskii ◽  
I. Ya Poddubnyi ◽  
L. S. Ivanova
Keyword(s):  
Molecular Weight ◽  
Functional Groups ◽  
Chemical Structure ◽  
Sol Gel ◽  
Average Molecular Weight ◽  
Dense Network ◽  
Green Strength ◽  
Gel Fraction ◽  
Rubber Compounds ◽  
Processing Properties

Abstract By changing the sol-gel ratio and the structure of the gel fraction it is possible to obtain various grades of synthetic cis-poly(isoprene) which show promise for different applications in the tire and mechanical rubber goods industries. The processability of commercial SKI-3 rubber (at a given average molecular weight of sol) depends mainly on the structure of the gel fraction. Thus, for example, inferior processing properties of rubber compounds is associated primarily with the presence of tight gel. The content and structure of the gel fraction also significantly affect plasto-elastic properties of raw rubbers, e.g. a low plasticity of raw rubbers owes to the increased content of gel fraction. The reduced green strength of compounds based on SKI—3 rubber is accounted for by its chemical structure. Conventional methods used to change the properties of rubbers (including the variation in molecular weight, molecular weight distribution, branching degree, and variation in the content and structure of gel fraction) cannot be considered to be adequate to tackle the problem of the green strength of SKI—3 black stocks. The way to solve the problem appears to be the introduction of functional groups into the polymer chain at the stage of synthesis or processing. These functional groups should be active as to the formation of labile rubber—carbon black—rubber and/or rubber—rubber bonds. High purity of microstructure is necessary but not sufficient for obtaining the required level of green strength of compounded SKI—3. The gel fractions of SKI—3 rubber yield vulcanizates with a more dense network than the corresponding sol vulcanizates. The temperature dependence of the tensile strength is controlled by the network density of vulcanizates from high cis-1,4 poly(isoprene).

scholarly journals DIALib-QC an assessment tool for spectral libraries in data-independent acquisition proteomics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Mukul K. Midha ◽  
David S. Campbell ◽  
Charu Kapil ◽  
Ulrike Kusebauch ◽  
Michael R. Hoopmann ◽  
...  
Keyword(s):  
Quality Control ◽  
Assessment Tool ◽  
Software Tool ◽  
Mass Range ◽  
Systematic Evaluation ◽  
Label Free ◽  
Mass Spectral ◽  
Data Independent Acquisition ◽  
Theoretical Mass ◽  
Spectral Libraries

Abstract Data-independent acquisition (DIA) mass spectrometry, also known as Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH), is a popular label-free proteomics strategy to comprehensively quantify peptides/proteins utilizing mass spectral libraries to decipher inherently multiplexed spectra collected linearly across a mass range. Although there are many spectral libraries produced worldwide, the quality control of these libraries is lacking. We present the DIALib-QC (DIA library quality control) software tool for the systematic evaluation of a library’s characteristics, completeness and correctness across 62 parameters of compliance, and further provide the option to improve its quality. We demonstrate its utility in assessing and repairing spectral libraries for correctness, accuracy and sensitivity.

scholarly journals An Unprecedented Medium-Chain Diunsaturated N-acylhomoserine Lactone from Marine Roseobacter Group Bacteria

Marine Drugs ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 20 ◽  
Author(s):  
Lisa Ziesche ◽  
Laura Wolter ◽  
Hui Wang ◽  
Thorsten Brinkhoff ◽  
Marion Pohlner ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Acyl Chain ◽  
Homoserine Lactone ◽  
Compound Identification ◽  
Structural Element ◽  
Mass Spectral ◽  
Acylhomoserine Lactone ◽  
The North ◽  
Bacterial Signaling ◽  
Roseobacter Group

N-acylhomoserine lactones (AHLs), bacterial signaling compounds involved in quorum-sensing, are a structurally diverse group of compounds. We describe here the identification, synthesis, occurrence and biological activity of a new AHL, N-((2E,5Z)-2,5-dodecadienoyl)homoserine lactone (11) and its isomer N-((3E,5Z)-3,5-dodecadienoyl)homoserine lactone (13), occurring in several Roseobacter group bacteria (Rhodobacteraceae). The analysis of 26 strains revealed the presence of 11 and 13 in six of them originating from the surface of the macroalgae Fucus spiralis or sediments from the North Sea. In addition, 18 other AHLs were detected in 12 strains. Compound identification was performed by GC/MS. Mass spectral analysis revealed a diunsaturated C12 homoserine lactone as structural element of the new AHL. Synthesis of three likely candidate compounds, 11, 13 and N-((2E,4E)-2,4-dodecadienoyl)homoserine lactone (5), revealed the former to be the natural AHLs. Bioactivity test with quorum-sensing reporter strains showed high activity of all three compounds. Therefore, the configuration and stereochemistry of the double bonds in the acyl chain seemed to be unimportant for the activity, although the chains have largely different shapes, solely the chain length determining activity. In combination with previous results with other Roseobacter group bacteria, we could show that there is wide variance between AHL composition within the strains. Furthermore, no association of certain AHLs with different habitats like macroalgal surfaces or sediment could be detected.

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