@article{HaebelBahrkePeter2007,
  author    = {Haebel, Sophie and Bahrke, Sven and Peter, Martin G.},
  title     = {Quantitative sequencing of complex mixtures of heterochitooligosaccharides by vMALDI-linear ion trap mass spectrometry},
  issn      = {0003-2700},
  doi       = {10.1021/Ac062254u},
  year      = {2007},
  abstract  = {Heterochitooligosaccharides possess interesting biol. properties. Isobaric mixts. of such linear heterochitooligosaccharides can be obtained by chem. or enzymic degrdn. of chitosan. However, the sepn. of such mixts. is a challenging anal. problem which is so far unresolved. It is shown that these isobaric mixts. can be sequenced and quantified simultaneously using std. derivatization and multistage tandem mass spectrometric techniques. A linear ion trap mass spectrometer equipped with a vacuum matrix-assisted laser desorption ionization (vMALDI) source is used to perform MS2 as well as MS3 expts. [on SciFinder (R)].},
  language  = {en}
}
@article{TsukamotoHaebelValencaetal.2008,
  author    = {Tsukamoto, Junko and Haebel, Sophie and Valenca, Gustavo P. and Peter, Martin G. and FRanco, Telma T.},
  title     = {Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides},
  issn      = {0268-2575},
  year      = {2008},
  abstract  = {Background: There is an increased need to replace materials derived from fossil sources by renewables. Sugar- cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the prepn. of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous prepn. of protected sugar derivs., such as glycosides, or activated acrylates, such as vinyl acrylate. Results: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of mol. sieves was investigated. The reactions were monitored by high-performance liq. chromatog. (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was obsd. for the D-glucose and D- fructose, followed by D-xylose and D-maltose. Mol. sieves had no pronounced effect on the conversion. Conclusions: A feasible method is described to produce and to characterize sugar acrylates, including those contg. more than two acrylate groups. The process for prodn. of these higher esters could potentially be optimized further to produce mols. for crosslinking in acrylate polymn. and other applications. The direct enzymic esterification of free carbohydrates with acrylic acid is unprecedented. [on SciFinder (R)].},
  language  = {en}
}
@article{HaebelHejaziFrohbergetal.2008,
  author    = {Haebel, Sophie and Hejazi, Mahdi and Frohberg, Claus and Heydenreich, Matthias and Ritte, Gerhard},
  title     = {Mass spectrometric quantification of the relative amounts of C6 and C3 position phosphorylated glucosyl residues in starch},
  issn      = {0003-2697},
  year      = {2008},
  abstract  = {The quantification of phosphate bound to the C6 and C3 positions of glucose residues in starch has received increasing interest since the importance of starch phosphorylation for plant metabolism was discovered. The method described here is based on the observation that the isobaric compounds glucose-6-phosphate (Glc6P) and glucose-3- phosphate (Glc3P) exhibit significantly different fragmentation patterns in negative ion electrospray tandem mass spectrometry (MS/MS). A simple experiment involving collision-induced dissociation (CID) MS2 spectra of the sample and the two reference substances Glc3P and Glc6P permitted the quantification of the relative amounts of the two compounds in monosaccharide mixtures generated by acid hydrolysis of starch. The method was tested on well-characterized potato tuber starch. The results are consistent with those obtained by NMR analysis. In contrast to NMR, however, the presented method is fast and can be performed on less than 1 mg of starch. Starch samples of other origins exhibiting a variety of phosphorylation degrees were analyzed to assess the sensitivity and robustness of the method.},
  language  = {en}
}
@article{HaebelPeterKatalinicPeter1997,
  author    = {Haebel, Sophie and Peter-Katalinic, Jasna and Peter, Martin G.},
  title     = {Mass spectrometry of chitooligosaccharides},
  isbn      = {88-86889- 01-1},
  year      = {1997},
  language  = {en}
}
@article{BahrkeEinarssonGislasonetal.2002,
  author    = {Bahrke, Sven and Einarsson, Jon M. and Gislason, Johannes and Haebel, Sophie and Letzel, Matthias C. and Peter-Katalinic, Jasna and Peter, Martin G.},
  title     = {Sequence analysis of chitooligosaccharides by matrix-assisted laser desorption ionization postsource decay mass spectrometry},
  year      = {2002},
  abstract  = {Oligosaccharides composed of 2-acetamido-2-deoxy-D-glucopyranose (GlcNAc) and/or 2-amino-2-deoxy-D- glucopyranose (GlcN) were prepd. by chem. degrdn. of chitin or chitosan and sepd. by gel permeation chromatog. Oligosaccharides obtained after enzymic hydrolysis of chitosan [FA 0.19] with a fungal chitinase were derivatized by reductive amination with 2-aminoacridone and sequenced by matrix-assisted laser desorption ionization time-of-flight postsource decay (PSD) mass spectrometry (MS). The sequence of a trimer, D1A2, was established as D-A-A. The compn. of a hexamer D3A3 was .apprx.65\% D-A-D-D-A-A and 35\% D-D-A-D-A-A. The PSD MS of a nonamer D5A4-amac revealed four isobaric species D-X-Y-D-X-Y-D-A-A, where A is GlcNAc, D is GlcN, and X and Y (X ¹ Y) are mutually either D or A. This structure motif was also obsd. in a dodecamer D7A5 which was composed of eight isobaric sequences of the general formula (D-X-Y)3- D-A-A.},
  language  = {en}
}
@article{BahrkeEinarssonGislasonetal.2003,
  author    = {Bahrke, Sven and Einarsson, Jon M. and Gislason, Johannes and Haebel, Sophie and Peter-Katalinic, Jasna},
  title     = {Characterization of chitooligosaccharides by mass spectrometry},
  isbn      = {82-471-5901-5},
  year      = {2003},
  abstract  = {Heterochitooligosaccharides of DP 6, DP 9, and DP 12 were evaluated using established methods of derivatization and matrix-assisted laser desorption ionization post source decay mass spectrometry.},
  language  = {en}
}
@article{StrehmelSarkerLahtietal.2005,
  author    = {Strehmel, Veronika and Sarker, A. M. and Lahti, P. M. and Karasz, F. E. and Heydenreich, Matthias and Wetzel, Hendrik and Haebel, Sophie and Strehmel, Bernd},
  title     = {One- and two-photon photochemistry and photophysics of poly(arylenevinylene)s containing a biphenyl moiety},
  issn      = {1439-4235},
  year      = {2005},
  abstract  = {Photochemical and photophysical properties were investigated for poly(arylenevinylene)s containing a flexible biphenyl "hinge" unit by applying one-photon (OP) and two-photon (TP) excitation to explore excited-state properties. The poly(arylenevinylene)s were poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(4,4'-dihexyloxy-3,3'-biph enylenevinylene)] (1), poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-dihexyloxy-3,3'-biph enylenevinylene)] (2), and poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-biphenylene-vinylene )] (3). Effective emission quantum yields and related photonic properties were evaluated on a realistic per-chromophore basis using effective conjugation lengths based on the Strickler-Berg relationship. intramolecular photocyclization was deduced to occur in the one case where the biphenyl molecular connectivity permitted the reaction, based on matrix- assisted loser desorption/ionization time-of-flight (MALDI-TOF), heteronuclear multiple-quantum coherence (HMQC)-NMR, and gel-permeation chromatography (GPC) results. The various photoprocesses could be induced by either OP or TP excitation, though the first excited singlet state is the photoactive state. The higher excitation energy 1 of the TP excited state favors indirect population of the S, state by electronic coupling between the TP and OP excited states [lambda(max)(TPE) (nm): 726; delta (GM)([9]): 1 = 229, 2 = 215, 3 = 109). Photochemical processes occurring from the lowest OP excited state (S-1) could therefore also be indirectly induced by TP excitation},
  language  = {en}
}