Filtern
Dokumenttyp
- Zeitschriftenartikel (13)
Sprache
- Englisch (13)
Schlagworte
- ICP-MS (3)
- MALDI (3)
- Isotope dilution analysis (2)
- Multivariate statistics (2)
- Pollen (2)
- Silver nanoparticles (2)
- A4F (1)
- Asymmetric flow filed-flow fractionation (1)
- Asymmetrical flow field flow fractionation (AF4) (1)
- Caesium (1)
- Capillary electrophoresis (1)
- Capillary electrophoresis (CE) (1)
- Carboxyl group (1)
- Crosslinking (1)
- DCTB (1)
- Dried droplet (1)
- Droplet (1)
- Field flow fractionation (1)
- HPLC (1)
- High performance liquid chromatography (1)
- Imaging MS (1)
- Ionization (1)
- MALDI Massenspektrometrie (1)
- MALDI TOF mass spectrometry (1)
- MALDI mass spectrometry (1)
- Mass spectrometry imaging (1)
- Matrix segregation (1)
- Mega-dalton (1)
- Molecular masses (1)
- Nanoparticle (1)
- Nanoparticles (1)
- Nanoparticles with same nominal diameter (1)
- Polymer (1)
- Polymerisation (1)
- Polymers (1)
- Polystyrene (1)
- Polyurethane (1)
- Quantification (1)
- Sample loss (1)
- Sample preparation (1)
- Speciation (1)
- Surface coating (1)
- Thermal degradation (1)
- Toxicology (1)
- Two-dimensional off-line coupling (1)
- UV degradation (1)
- Ultraschallfalle (1)
Organisationseinheit der BAM
RATIONALE
A fast and reliable online identification of pollen is not yet available. The identification of pollen is based mainly on the evaluation of morphological data obtained by microscopic methods.
METHODS
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) was applied to the analysis of extracts and milled pollen samples. The obtained MALDI data were explored for characteristic peak patterns which could be subjected to a multivariate statistical analysis.
RESULTS
Two sample preparation methods are presented, which require only minimal or no chemical extraction of the pollen. MALDI pollen spectra could be recorded showing various peak patterns. A multivariate statistics approach allowed the classification of pollen into clusters indicating similarities and differences between various species.
CONCLUSIONS
These results demonstrate the potential and the reliability of MALDI-TOF MS for the identification and, in combination with multivariate statistics, also for the classification of pollen.
Molecular masses and end groups of polystyrene (PS) formed in a novel container-less polymerization strategy, based on levitated droplets in an acoustic trap, were determined by Gel Permeation Chromatography (GPC) and Matrix-assisted Laser Desorption/Ionization Time of Flight Mass spectrometry (MALDI-TOF MS).
Matrix-assisted laser desorption/ionization-timeof-flight (MALDI-TOF) imaging of polystyrenes with various molecular masses was applied to study spatial molecular mass distribution of polymers in sample spots prepared by the 'dried droplet' method. When different solvents and target surfaces were examined, a segregation of single homologous polymers was observed depending upon the evaporation rate of the solvent. For the observed Patterns left by the evaporating droplet, a hypothesis is offered taking into account different hydrodynamic interactions and diffusion.
The results illustrate that spot preparation using the conventionally 'dried droplet' method is prone to artifacts and should be avoided for reliable and reproducible MALDI mass spectrometry experiments with regards to the Determination of molecular masses and mass distributions.