title: Gas chromatographic-mass spectrometric fragmentation study of phytoestrogens as their trimethylsilyl derivatives: identification in soy milk and wastewater samples.
abstract: An analytical method for the identification of eight plant phytoestrogens (biochanin A, coumestrol, daidzein, equol, formononetin, glycitein, genistein and prunetin) in soy products and wastewater samples was developed using gas chromatography coupled with ion trap mass spectrometry (GC/MS-MS). The phytoestrogens were derivatized as their trimethylsilyl ethers with trimethylchlorosilane (TMCS) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The phytoestrogens were isolated from all samples with liquid-liquid extraction using ethyl acetate. Daidzein-d(4) and genistein-d(4) labeled standards were used as internal standards before extraction and derivatization. The fragmentation patterns of the phytoestrogens were investigated by isolating and fragmenting the precursor ions in the ion-trap and a typical fragmentation involved the loss of a methyl and a carbonyl group. Two characteristic fragment ions for each analyte were chosen for identification and confirmation. The developed methodology was applied to the identification and confirmation of phytoestrogens in soy milk, in wastewater effluent from a soy-milk processing plant, and in wastewater (influent and effluent) from a treatment plant. Detected concentrations of genistein ranged from 50,000 microg/L and 2000 microg/L in soy milk and in wastewater from a soy-plant, respectively, to 20 microg/L and <1 microg/L for influent and effluent from a wastewater treatment plant, respectively.
authors: Department of Environmental Engineering, Center for Environmental Mass Spectrometry, University of Colorado, Boulder, CO 80309, USA. imferrer@ono.com
authors: Imma
authors: I
authors: Ferrer
authors: Larry B
authors: LB
authors: Barber
authors: E Michael
authors: EM
authors: Thurman
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D048789:Phytoestrogens / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041942:Soy Milk / Q000737:chemistry*; D014297:Trimethylsilyl Compounds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D048789:Phytoestrogens; D014297:Trimethylsilyl Compounds; D014874:Water Pollutants, Chemical; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide; C039293:trimethylchlorosilane