Title of article :
Determination of free sulfite in wine by zone electrophoresis with isotachophoresis sample pretreatment on a column-coupling chip
Author/Authors :
Masar Gashi، نويسنده , , Mari?n and Dankov?، نويسنده , , Mariana and ?lveck?، نويسنده , , Eva and Stachurov?، نويسنده , , Adela and Kaniansky، نويسنده , , Du?an and Stanislawski، نويسنده , , Bernd، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Pages :
9
From page :
31
To page :
39
Abstract :
This work deals with the determination of free sulfite in wine by zone electrophoresis (ZE) with on-line isotachophoresis (ITP) sample pretreatment on a column-coupling (CC) chip with conductivity detection. A rapid pre-column conversion of sulfite to hydroxymethanesulfonate (HMS), to minimize oxidation losses of the analyte, was included into the developed analytical procedure, while ITP and ZE were responsible for specific analytical tasks in the separations performed on the CC chip. ITP, for example, eliminated the sample matrix from the separation compartment and, at the same time, provided a selective concentration of HMS before its transfer to the ZE stage of the separation. On the other hand, ZE served as a final separation (destacking) method and it was used under the separating conditions favoring a sensitive conductivity detection of HMS. In this way, ITP and ZE cooperatively contributed to a 900 μg/l concentration detectability for sulfite as attained for a 60 nl load of wine (a 15-fold wine dilution and the use of a 0.9 μl sample injection channel of the chip) and, consequently, to the determination of free sulfite when this was present in wine at the concentrations as low as 3 mg/l. The separations were carried out in a closed separation compartment of the chip with suppressed hydrodynamic and electroosmotic flows. Such transport conditions, minimizing fluctuations of the migration velocities of the separated constituents, made a frame for precise migration and quantitation data as achieved for HMS in both the model and wine samples. Ninety percent recoveries, as typically obtained for free sulfite in wine samples, indicate promising potentialities of the present method as far as the accuracies of the provided analytical results are concerned.
Keywords :
Wine , Food analysis , Chip technology , Column-coupling electrophoresis chip , Isotachophoresis , Sample preparation , Sulfite
Journal title :
Journal of Chromatography A
Serial Year :
2004
Journal title :
Journal of Chromatography A
Record number :
1519708
Link To Document :
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