Steviol quantification at the picomole level by high-performance liquid chromatography.
J Agric Food Chem
; 52(9): 2445-9, 2004 May 05.
Article
in En
| MEDLINE
| ID: mdl-15113139
ABSTRACT
A simple and highly sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) has been developed for the determination of steviol (SV) using dihydroisosteviol (DHISV) as an internal standard (IS). SV and DHISV were derivatized by reaction of the acids with 4-(bromomethyl)-7-methoxycoumarin in an aprotic solvent (DMF or acetone). The resulting ester derivatives were separated on an ODS column (250 x 4.6 mm i.d., 5 microm particle size) using fluorescence detection with excitation at 321 nm and emission at 391 nm. The mobile phase consisted of acetonitrile/water (8020 v/v) with a flow rate of 1 mL min(-)(1). A linear relationship was observed for concentrations between 0.5 and 50 microg/mL of SV, and the detection limit was 100 pg. For application of this method to samples of beer fortified with stevioside, a simple procedure for extraction of the beer with diethyl ether and derivatization in DMF was applied. Whereas beer samples spiked with SV gave a linear response over the range 0.1-15 microg/mL beer, no SV could be detected in beer samples enriched in stevioside that had been stored for over 3 years. The application of the method to plant samples involved preparation of an acid fraction containing the SV analyte, derivatization, and sample cleanup using small silica columns and thin-layer chromatography. A sensitive determination of 594 ng of steviol present in 100 mg of dry plant material was performed with high precision and accuracy.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chromatography, High Pressure Liquid
/
Diterpenes, Kaurane
/
Diterpenes
/
Microchemistry
Type of study:
Diagnostic_studies
Language:
En
Journal:
J Agric Food Chem
Year:
2004
Type:
Article
Affiliation country:
Belgium