title: Study of molar response of dextrans in electrochemical detection.
abstract: In this work, a methodological approach is reported, aimed at assessing the electrochemical response of some model gluco-oligosaccharides (dextrans). Such strategy is based on the complementary use of both anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and capillary zone electrophoresis coupled with UV detection (CZE-UV). Unlike HPAEC-PAD, CZE-UV required derivatization with a chromophoric dye (i.e., 8-aminonaphtalene-1,3,6-trisulphonic acid, ANTS) to enhance UV response and separation selectivity. From the comparison between chromophore response and PAD signal, the reliability of HPAEC-PAD for quantitative evaluation of dextran mixtures containing mainly oligomers with polymerization degree (DP) up to 18 could be proved, due to the fairly constant molar response. For higher DPs (up to 41), a maximum in the trend of the molar responses was observed followed by a steep decrease for DPs higher than about 30-35; indeed, an underestimation of weight-average molecular weight of dextran mixtures containing such oligomers was noticed.
authors.affiliation: Dionex SpA, San Donato Milanese, Milano, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Abballe
authors.forename: Mila
authors.initials: M
authors.lastname: Toppazzini
authors.forename: Cristiana
authors.initials: C
authors.lastname: Campa
authors.forename: Fulvio
authors.initials: F
authors.lastname: Uggeri
authors.forename: Sergio
authors.initials: S
authors.lastname: Paoletti
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003911:Dextrans / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D019075:Electrophoresis, Capillary; D008970:Molecular Weight; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D003911:Dextrans