Mass spectrometry molecular weight

The mass spectrometry molecular weight is based on the mass of the more/most abundant isotope of each element, and for C284H432N84O79S7 is therefore ... 

Mass spectrometry Molecular weight (post-translational modifications)... 

Matrix assisted laser desorption ionization - time of flight mass spectrometry MDL Drug Data Report Molecular Design Limited Molecular orbital Mass spectrometry Molecular weight National Cancer Institute Neurokinin... 

Various techniques have been used depending on the polymer and the nature of the chemical transformations infrared, ultraviolet and electron spin resonance spectroscopy, vapour phase chromatography, mass spectrometry, molecular weight and gel fraction determination, luminescence measurements, etc. These techniques have recently been discussed in a well-documented review on analytical methods applied to the study of the photodegradation of polymers [19]. 

Montaudo, G., Montaudo, M.S., Puglisi, C., and Samperi, F. Characterization of polymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry molecular weight estimates in samples of varying polydisjjersity. Rapid Commun. Mass Spectrom, 9, 453 (1995). 

Mass Spectrometry Usage of analytical devices that can determine the mass (or molecular weight) of proteins and nucleic acids, the sequence of protein molecules, the chemical organization of almost all substances and the identification of gram-negative and gram-positive microorganisms. 

Mass spectrometry is the study of the mass, or molecular weight, of ions created via ionization or fragmentation and determined electrically in the gas phase. In the study of polymers, mass spectrometry has two broad applications ... 

Ultraviolet visible (UV VIS) spectroscopy, which probes the electron distribution especially m molecules that have conjugated n electron systems Mass spectrometry (MS), which gives the molecular weight and formula both of the molecule itself and various structural units within it... 

As we have just seen interpreting the fragmentation patterns m a mass spectrum m terms of a molecule s structural units makes mass spectrometry much more than just a tool for determining molecular weights Nevertheless even the molecular weight can provide more information than you might think... 

Amines have odd numbered molecular weights which helps identify them by mass spectrometry Fragmentation tends to be controlled by the formation of a nitrogen stabilized cation... 

Analytical Approaches. Different analytical techniques have been appHed to each fraction to determine its molecular composition. As the molecular weight increases, complexity increasingly shifts the level of analytical detail from quantification of most individual species in the naphtha to average molecular descriptions in the vacuum residuum. For the naphtha, classical techniques allow the isolation and identification of individual compounds by physical properties. Gas chromatographic (gc) resolution allows almost every compound having less than eight carbon atoms to be measured separately. The combination of gc with mass spectrometry (gc/ms) can be used for quantitation purposes when compounds are not well-resolved by gc. 

Mass Spectrometry. Field desorption mass spectrometry has been used to analy2e PPO (179). Average molecular weight parameters (M and could be determined using either protonated (MH + ) or cation attachment (MNa + ) ions. Good agreement was found between fdms and data supphed by the manufacturer, usually less than 5% difference in all cases up to about 3000 amu. Laser desorption Fourier transform mass spectrometry was used to measure PPG ion and it was claimed that ions up to m/2 9700 (PEG) can be analy2ed by this method (180). 

The use of separation techniques, such as gel permeation and high pressure Hquid chromatography interfaced with sensitive, silicon-specific aas or ICP detectors, has been particularly advantageous for the analysis of siUcones in environmental extracts (469,483—486). Supercritical fluid chromatography coupled with various detection devices is effective for the separation of siUcone oligomers that have molecular weights less than 3000 Da. Time-of-flight secondary ion mass spectrometry (TOF-sims) is appHcable up to 10,000 Da (487). 

The analysis of penicillins by mass spectrometry (qv) has developed with the advent of novel techniques such as fast atom bombardment. The use of soft ionization techniques has enabled the analysis of thermally labile nonvolatile compounds. These techniques have proven extremely valuable in providing abundant molecular weight information from underivatized penicillins, both as free acids and as metal salts (15). 

In an attempt to isolate a factor responsible for stimulating hepatocyte growth. Nelson et al. (31) used a PolyHEA column to fractionate an extract of liver by size. The active fraction eluted at a position corresponding to approximately 200 Da the actual molecular weight (electrospray mass spectrometry ES-MS) was 215 Da. The compound of interest proved to be glycerophosphorylethano-lamine. 

At its simplest, mass spectrometry (MS) is a technique for measuring the mass, and therefore the molecular weight (MW), of a molecule. In addition, it s often possible to gain structural information about a molecule by measuring the masses of the fragments produced when molecules are broken apart. 

What kinds of information can we get from a mass spectrum Certainly the most obvious information is the molecular weight, which in itself can be invaluable. For example, if we were given samples of hexane (MW = 86), 1-hexene (MW = 84), and 1-hexyne (MW = 82), mass spectrometry would easily distinguish them. 

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