title: Effects of extraction and high-performance liquid chromatographic conditions on the determination of lutein in spinach.
abstract: A major factor in the direct determination of lutein in spinach extracts proved to be obtaining reproducible and stable chromatography of lutein. This was achieved on a C30 column with the mobile phase acetone-0.1M triethylammonium acetate (TEAA) buffer (pH 7) 9:1 (v/v). Extraction of 10mg of lyophilized spinach with 10 mL of extraction solvent (ethanol, acetone, ethanol-ethyl acetate 1:1 (v/v), methanol-THF 1:1 (v/v)) for 15 min with magnetic stirring under nitrogen resulted in equal yields of lutein. The yields were enhanced by addition of 15% of 1M TEAA buffer pH 7 to all four extraction solvents. As confirmed by recovery experiments, no loss of lutein occurred during the extraction. The relative standard deviation from triplicate extractions was less than 5%. The addition of 15% TEAA pH 7 to acetone enhanced the extraction yield of lutein also from unlyophilized spinach. The content of lutein in different spinach samples ranged from 5 to 15 mg/100g of fresh weight. The first separation is reported of all the carotenoids and chlorophylls on a C18 core-shell column and the addition of 15% of 1M TEAA buffer pH 7 to acetone also enhanced the extraction yield of β-carotene compared to the yield produced by pure acetone.
authors: National Institute of Chemistry, Laboratory for Food Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. breda.simonovska@ki.si
authors: Breda
authors: B
authors: Simonovska
authors: Irena
authors: I
authors: Vovk
authors: Vesna
authors: V
authors: Glavnik
authors: Katarina
authors: K
authors: Cernelič
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005612:Freeze Drying; D006863:Hydrogen-Ion Concentration; D014975:Lutein / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D018724:Spinacia oleracea / Q000737:chemistry*
chemical_list: D014975:Lutein