IBAM   22618
INSTITUTO DE BIOLOGIA AGRICOLA DE MENDOZA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
DETERMINATION OF PHENOLIC COMPOUNDS IN NECTAR BY SOLID PHASE EXTRACTION-CAPILLARY ZONE ELECTROPHORESIS
Autor/es:
SOTO V.; FERNANDEZ M.A.; GATICA I.; SILVA M.
Lugar:
Buenos Aires
Reunión:
Simposio; LACE 2012 18th Latin-American Symposium; 2012
Institución organizadora:
LACE
Resumen:
Phenolic compounds are one of the most important groups of compounds occurring in fruits, vegetables, seeds, and flowers, where they are widely distributed. Phenolic substances are quite widespread in nectars. Their accumulation may make the nectar toxic, so that it then becomes repellent to some visitors. CE is becoming increasingly recognized as an important analytical separation technique due to its speed, efficiency, reproducibility, ultrasmall sample volume requirements. However, so far, this technique has not been explored for the analysis of nectar. The aims of our work were to develop a method for routine analysis of phenolic compounds in nectar; and to isolate these components in the nectar of different plant species. Phenolic compounds for CZE analysis were extracted from nectar samples (250 µg), which were homogenized in Milli-Q water (1:5, w/v) at pH 2 adjusted with HCl. The solutions were then extracted using a C18 cartridge, previously activated with methanol (5 mL) followed by acidic water (5 mL). The phenolic compounds remain in the column while sugars and other polar compounds elute with the aqueous solvent, resulting in a flavonoid recovery of >95%. The column was rinsed with 1 mL of acidic water. The phenolic fraction was eluted with 500 µL of methanol. The separations were undertaken in a 50 cm effective length, 75 mm ID, and 375 mm fused silica capillary. Separation voltage of 25 kV in a 30 mM boric acid running buffer (pH 9.5), The capillary temperature was 25 ºC. Samples were injected for 5 s. Electropherograms were recorded at 290 nm. Under the optimum conditions, the simultaneous determination of 12 phenolic components (catechin, naringenin, rutin, cinnamic acid, syringic acid, chlorogenic acid, apigenin, vanillic acid, luteolin, quercetin, caffeic acid, and gallic acid) could be well separated. The procedure was successfully used for the analysis and comparison of the phenolic content of nectar samples originating from different flowers.