TY  - JOUR
A1  - Vijayakrishnan, Balakumar
A1  - Issaree, Arisara
A1  - Corilo, Yuri E.
A1  - Ferreira, Christina Ramires
A1  - Eberlin, Marcos N.
A1  - Peter, Martin G.
T1  - MSn of the six isomers of (GlcN)(2)(GlcNAc)(2) aminoglucan tetrasaccharides (diacetylchitotetraoses) rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides
JF  - Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides
N2  - The six possible isomers of di-N-acetylchitotetraoses [AADD, ADDA, ADAD, DADA, DAAD, and DDAA, where D stands for 2-amino-2-deoxy-3-D-glucose (GlcN) and A for 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc)] were analyzed by ESI(+)-MSn. Collision induced dissociation via MSn experiments were performed for the sodiated molecules of m/z 769 [M+Na](+) for each isomer, and fragments were generated mainly by glycosidic bond and cross-ring cleavages. Rules of fragmentation were then established. A reducing end D residue yields the (O.2)A(4) cross-ring [M-59+Na](+) fragment of m/z 710 as the most abundant, whereas isomers containing a reducing end A prefer to lose water to form the [M-18+Na](+) ion of m/z 751, as well as abundant (O.2)A(4) cross-ring [M-101+Na](+) fragments of m/z 668 and B-3 [M-221+Na](+) ions of m/z 548. MS3 of C- and Y-type ions shows analogous fragmentation behaviour that allows identification of the reducing end next-neighbour residue. Due to gas-phase anchimeric assistance, B-type cleavage between the glycosidic oxygen and the anomeric carbon atom is favoured when the glycon is an A residue. Relative ion abundances are generally in the order B >> C > Y, but may vary depending on the next neighbour towards the non-reducing end. These fragmentation rules were used for partial sequence analysis of hetero-chitooligosaccharides of the composition D(2)A(3), D(3)A(3), D(2)A(4), D(4)A(3), and D(3)A(4).
KW  - Chitosan
KW  - Fragmentation
KW  - Oligosaccharides
KW  - Sequence analysis
KW  - Tandem mass spectrometry
Y1  - 2011
U6  - https://doi.org/10.1016/j.carbpol.2010.04.041
SN  - 0144-8617
VL  - 84
IS  - 2
SP  - 713
EP  - 726
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Raju, Rajarshi Roy
A1  - Liebig, Ferenc
A1  - Klemke, Bastian
A1  - Koetz, Joachim
T1  - pH-responsive magnetic Pickering Janus emulsions
JF  - Colloid and polymer science : official journal of the Kolloid-Gesellschaft
N2  - We report ultrasonically generated pH-responsive Pickering Janus emulsions of olive oil and silicone oil with controllable droplet size and engulfment. Chitosan was used as a pH-responsive emulsifier. The increase of pH from 2 to 6 leads to a transition from completely engulfed double emulsion droplets to dumbbell-shaped Janus droplets accompanied by a significant decrease of droplet diameter and a more homogeneous size distribution. The results can be elucidated by the conformational change of chitosan from a more extended form at pH 2 to a more flexible form at pH 4-5. Magnetic responsiveness to the emulsion was attributed by dispersing superparamagnetic nanoparticles (Fe3O4 with diameter of 13 +/- 2 nm) in the olive oil phase before preparing the Janus emulsion. Incorporation of magnetic nanoparticles leads to superior emulsion stability, drastically reduced droplet diameters, and opened the way to control movement and orientation of the Janus droplets according to an external magnetic field.
KW  - Janus emulsion
KW  - Chitosan
KW  - pH-responsive
KW  - Magnetic-responsive
KW  - Cryo-SEM
KW  - TEM
Y1  - 2018
U6  - https://doi.org/10.1007/s00396-018-4321-z
SN  - 0303-402X
SN  - 1435-1536
VL  - 296
IS  - 6
SP  - 1039
EP  - 1046
PB  - Springer
CY  - New York
ER  -