TY  - JOUR
A1  - Piekarczyk, Andreas
A1  - Heitmann, Ulrike
A1  - Weiß, Karl-Anders
A1  - Köhl, Michael
A1  - Bald, Ilko
T1  - Development of a simple setup for temperature dependent mass spectrometric measurements for the investigation of outgassing effects in polymeric materials for solar application
JF  - Polymer testing
N2  - A simple experimental setup for temperature dependent mass spectrometric measurements has been constructed. It consists of a heated sample chamber and a mass spectrometer and allows for measurements under inert gas and ambient air. Based on initial measurements on two extruded polystyrene (XPS) samples a methodology for the data analysis has been developed. With this methodology the outgassing temperature of volatile compounds, which were used as blowing agents, has been identified. Furthermore, the composition of the blowing agents has been analyzed by temperature dependent mass spectra. The results indicate the use of ambient air in one material and a mixture of the banned blowing agents R142b and R22, both hydrochlorofluorocarbons (HCFC), in the other material. The here described methodology provides an easy to use approach to identify such compounds, for example as part of environmental or quality control.
Y1  - 2019
U6  - https://doi.org/10.1016/j.polymertesting.2019.106164
SN  - 0142-9418
SN  - 1873-2348
VL  - 81
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Piekarczyk, Andreas
A1  - Bald, Ilko
A1  - Flosadottir, Helga D.
A1  - Omarsson, Benedikt
A1  - Lafosse, Anne
A1  - Ingolfsson, Oddur
T1  - Influence of metal ion complexation on the metastable fragmentation of DNA hexamers
JF  - The European physical journal : D, Atomic, molecular, optical and plasma physics
N2  - Here, we study the metastable decay of 5'-d(TTGCTT) in the presence of 0-6 alkaline metal ions (Li+, Na+, K+, Rb+) and 0-3 alkaline earth metal ions (Mg2+ and Ca2+), which replace the corresponding number of protons in the oligonucleotide. We find that all ions studied here stabilize the oligonucleotide with respect to simple 3'-C-O backbone cleavage, but at the same time these metal ions promote a central oligonucleotide deletion accompanied by a concomitant recombination of the terminal d(TT) groups. We find that the quenching of the 3'-C-O backbone cleavage is not ion specific, since it is due to the removal of the phosphate protons upon replacement with the respective metal ions. The central nucleotide deletion competes with the 3'-C-O backbone cleavage channels and is thus promoted through the replacement of the exchangeable protons against metal ions. However, with increasing positive charge density of the metal ions the yield of the central nucleotide deletion further increases. We attribute this effect to the necessity of sufficient proximity of the terminal d(TT) group to allow for their recombination on this reaction path. Hence, the formation of a reactive conformer is mediated by the metal ions.
Y1  - 2014
U6  - https://doi.org/10.1140/epjd/e2014-40838-7
SN  - 1434-6060
SN  - 1434-6079
VL  - 68
IS  - 6
PB  - Springer
CY  - New York
ER  -