Other mass spectrometric techniques

Thermal degradation mechanisms have been more recently studied by successfully applying less traditional MS techniques. Altintas et al. investigated via SEC-ESI-MS the degradation processes of linear RAFT PS and polyacrylate bearing trithiocarbon-ate functionality in the middle of the polymer chain with various chain lengths. The thermal stability behaviour of the polymers was studied in air and in inert atmosphere at temperatures ranging from 100 C to 200 C for up to 504 h (3 weeks). Under inert 

Li et al. reported a new application of synchrotron VUV photoionisation MS in thermal decomposition studies of polymers, and displayed its good performance in product analysis helpful to understand the thermal decomposition mechanisms of PVC and PS, extensible to other synthetic polymers. Pyrolysis products of PVC and PS formed at different temperatures were identified by the measurement of photoionisation mass spectra at different photon energies. The experimental results showed the differences of the pyrolysis product pool of PVC at different temperatures, and established that the thermal decomposition process occurred into two steps the low-temperature step to form HCl and benzene, and the high-temperature stage to form several large aromatic hydrocarbons. For the thermal decomposition of PS, four reaction categories were determined [181]. 

Barr re et al. extended the use of atmospheric solid analysis probe (ASAP) combined with travelling wave ion mobility mass spectrometry (TWIM-MS) for the 

PP2 and (c) PP3. (d) Structiues proposed by Lattimer for the six distributions of PP pyrolysis residue observed by Py-GC/MS. Adapted from Ref [183] with kind permission of the ACS. 

MS represent a well-established and traditionally used method to examine polymer degradation. Several classical methods have proved very successful at studying polymer degradation mechanisms (e.g. IR and UV/visible spectroscopies, NMR, SEC). This chapter wants to answer the question What does mass spectrometry have to offer additionally in polymer degradation studies  

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This relatively new method is quite different from other mass spectrometric techniques usually used for this topic. ToF-SIMS presents two main advantages. First, it permits the analysis of solid samples with minimal sample preparation. This avoids the necessity of extractions, and therefore, it can be very useful for small and precious samples. 

In contrast to all other mass spectrometric techniques, in secondary ion mass spectrometry (SIMS) the relative sensitivity coefficients of elements show a very strong variation, from the matrix and experimental conditions used, of up to six orders of magnitude. The RSCs vary considerably in... 

Other mass spectrometric techniques such as RIMS and AMS possess high isotope selectivity for extreme ultratrace and isotope analysis of, in particular, radiotoxic isotopes ( C, "Ca, Sr, Tc, Pb, U and plutonium isotopes) in the environment, in cosmochemistry, radiodating, nutrition and biomedical research. RIMS has become as an nltrasensitive and selective analytical technique for the determination of extremely low isotope abundances. In spite of the excellent analytical features of RIMS (detection limit for isotopes 10 atoms per sample) and exciting applications for the determination of extremely low abundances and isotope ratios of long-lived radionuclides, such as all plutonium isotopes (including Pu), U or " Ca, but no commercial instrument is available on the analytical market. 

When the analytes to be identified or quantified are polar or have a high molecular weight, LCMS should be considered over other mass spectrometric techniques. Some examples follow. 

ABSTRACT. Details of the novel method of laser evaporation of intact neutral molecules (LEIM) with a low powered IR-laser and the multiphoton ionization (MUPI) combined with a high-resolution Reflectron-Time-of-Flight (RETOF) mass spectrometer are explained. Some features of the method are discussed. Mass Spectra of biomolecules obtained with this method are displayed and their differences to other mass spectrometric techniques are discussed. It is shown, that Multiphoton Ionization is a general activation method for forming ions in a mass spectrometer, with additional features for an easy deducing of structures and intrinsic properties of biomolecules in contrast to other mass spectrometric ionization methods. 

Other Mass Spectrometric Techniques Related to Cosmochemical... 

Even with improvements like MIC and automatic control of the electrode positions [128], SSMS fell out of favor because of the complex and expensive instruments, the rather time-consuming analysis, and the improvements of other mass spectrometric techniques. Few systems are still operational, but sale of commercial instruments stopped already in 1997. 

Highlights The main interest in studies of uranium content in oceans or seawater is to determine the effect of anthropogenic activities. Therefore, the presence and abundance of the minor isotopes, particularly U, must be accurately determined, and this requires preconcentration and separation of the uranium and the use of accelerator mass spectrometry (AMS) for the analysis. Other mass spectrometric techniques (ICPMS or TIMS) can also be used but with inferior performance. The high salinity of ocean water introduces a matrix effect that could bias ICPMS measurements of the uranium content, so the separation and preconcentration methods described earlier may be needed for precise quantification of uranium (an internal standard can also be used for this purpose). 

SIMS can be summarized as a mass spectrometric technique that is applicable to solids (most other mass spectrometric techniques require the sample to be in the liquid or gaseous state). Mass spectrometric techniques differentiate between the different elements and molecules based on their mass-to-charge ratio. To simplify matters, the vast majority exists in the -l-l or -1 charge state. Their mass, in turn, is defined by the number of protons and neutrons making np the element with molecules made up of elements. Note All matter is made up of the elements with the physical properties of matter thus derivable from the elements present and the way in which they are bound. 

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