title: Microwave-assisted extraction coupled with single drop microextraction and high-performance column liquid chromatography for the determination of trace estrogen adulterants in soybean isoflavone dietary supplements.
abstract: A sensitive and accurate method consisting of microwave-assisted extraction (MAE) coupled with single drop microextraction (SDME) and HPLC was developed for the determination of four trace estrogen adulterants, including estriol (E3), estradiol (E2), ethinyl estradiol (EE), and estrone (E1), in different soybean dietary supplements. The samples were extracted by MAE; the extracts were cleaned up and enriched by SDME, and then analyzed by HPLC. The conditions of MAE were optimized, and the effects of solvent and extraction time in SDME on the enrichment capacity were studied. The enrichment factors of E3, E2, EE, and E1 under the optimized conditions were 247-, 335-, 316-, and 319-fold, respectively. The linear range of the MAE-SDME-HPLC method ranged from 5.0 to 180.0 microg/L, and the detection limit from 1.1 to 1.2 microg/L. The RSD ranged from 7.9 to 9.6%. Three soybean dietary supplements, including oral liquid, capsule, and tablet forms, were analyzed. The spike recovery was more than 70%, with RSD lower than 13.2%. It was shown that the proposed method was accurate, sensitive, and suitable for the determination of trace analytes in complex samples.
authors.affiliation: Sun Yat-Sen University, School of Chemistry and Chemical Engineering, Guangzhou 510275, People's Republic of China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Xiao
authors.forename: Yi
authors.initials: Y
authors.lastname: Yin
authors.forename: Yuling
authors.initials: Y
authors.lastname: Hu
authors.forename: Gongke
authors.initials: G
authors.lastname: Li
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D004340:Drug Contamination; D004967:Estrogens / Q000032:analysis*; D007529:Isoflavones / Q000032:analysis*; D008872:Microwaves; D013025:Glycine max / Q000737:chemistry*
chemical_list: D004967:Estrogens; D007529:Isoflavones