INQUISAL   20936
INSTITUTO DE QUIMICA DE SAN LUIS "DR. ROBERTO ANTONIO OLSINA"
Unidad Ejecutora - UE
artículos
Título:
On-line preconcentration method using normal stacking mode and dynamic pH junction for the quality control of herbal medicinal products
Autor/es:
ACOSTA, GIMENA; ARCE, SILVIA; ORTEGA, CLAUDIA; MARTINEZ, LUIS DANTE; GOMEZ, MARÍA ROXANA
Revista:
CURRENT ANALYTICAL CHEMISTRY
Editorial:
BENTHAM SCIENCE PUBL LTD
Referencias:
Lugar: Oak Park; Año: 2011
ISSN:
1573-4110
Resumen:
An on-line preconcentration capillary electrophoresis (CE) methodology, which combines a normal stacking mode (NSM) with a dynamic pH junction technique, is introduced in this paper. A systematic study of the parameters (concentration and pH value of background electrolyte, composition of sample matrix, injection pressure and time, separation voltage and temperature) affecting on-line concentration of seven related phenolic compounds were investigated and optimized. Under the optimum focusing conditions, about 54-fold improvement in the detection sensitivity was obtained compared with usual hydrodynamic sample injection (0.5 psi, 5 s) without detriment in separation efficiency. In particular, the concentration limits of detection (LOD) (S/N = 3) for the phenolic compounds obtained after preconcentration were from 6.0 to 11.0 ng mL-1 with UV detection without any pretreatment procedure. The proposed method has been validated with RSD values between 1.13% and 1.98% for migration times and between 1.28% and 4.65% for peak areas. Developed NSM-dynamic pH junction method was applied to determination of related phenolic compounds in labeled Melissa officinalis medicinal herbal products commercialized in our country.