Quantification of Six Phytoestrogens at the Nanogram per Liter Level in Aqueous Environmental Samples Using ¹³C₃-Labeled Internal Standards

Abstract

In light of the estrogenic potentials and the recent concentration levels found for six phytoestrogens in surface waters, detailed monitoring and assessment of potential input sources are required. An accurate, precise, and sensitive HPLC-MS/MS analytical method incorporating five (13)C 3-labeled internal standards for the quantification of these plant estrogens in various aqueous environmental samples is presented here for the first time. The compounds investigated included biochanin A, daidzein, equol, formononetin, genistein, and coumestrol. The use of [ (13)C 3]biochanin A, [ (13)C 3]daidzein, [ (13)C 3]equol, [ (13)C 3]formononetin, and [ (13)C 3]genistein ensured an accurate quantification of the target analytes unaffected by matrix effects and analyte losses. Absolute method recoveries for all analytes ranged from 63 to 105%, from 63 to 99%, and from 73 to 133%, relative recoveries from 90 to 132%, from 89 to 139%, and from 89 to 115%, method detection levels from 0.5 to 2.7 ng/L, from 0.5 to 2.6 ng/L, and from 0.4 to 11.0 ng/L, and precision from 1 to 19%, from 1 to 16%, and from 1 to 11% in drainage water, river water, and WWTP effluent, respectively. The validated analytical method was applied in investigating the emission of the phytoestrogens via drainage water from a pasture containing 43% red clover ( Trifolium pratense) and in monitoring their occurrence in Swiss surface waters. Isoflavone concentrations ranging from 4 to 157 ng/L and up to 22 ng/L were found in drainage and river water, respectively.

Phytoestrogens and Mycotoxins in Iowa Streams: An Examination of Underinvestigated Compounds in Agricultural Basins

“…and soybean [ Glycine max (Merr.) L.] (Sivesind and Seguin, 2005; Morrison et al, 2008), some fraction of which may be released from agricultural crops and fields into the environment (Erbs et al, 2007; Hoerger et al, 2009). Additional pathways to the environment for phytoestrogens can be from human and animal excretion after plant consumption (Burnison et al, 2003; Heinonen et al, 2004; Ferrer et al, 2009; Kang and Price, 2009; Bester et al, 2010).…”

Estrogenic activity in drainage water: a field study on a Swiss cattle pasture

“…For budget reasons, analysis of phytoestrogens was limited to six phytoestrogens common in Swiss rivers: daidzein, genistein, coumestrol, equol, formonetin and biochanin A (selection based on [43]). The frozen sample bottles were brought to ART, thawed, spiked with an isotope-labelled internal standard, solid-phase extracted and analysed with LC/MS/MS as described by Erbs et al [44].…”

Rejection and adsorption behaviour of phytoestrogens by nanofiltration and reverse osmosis membranes

“…They can be found in soy and other legumes and a range of vegetables and fruits [1]. The discharge of phytoestrogens from municipal wastewaters, surface waters and food production plants are regarded as the main sources in the natural aqueous environment [2]. The presence of phytoestrogens in the effluent of wastewater treatment plants (WWTPs), receiving waters and some treated drinking waters has received much attention and concern.…”

“…Lundgren and Novak [4] found that the concentration of phytoestrogens in industrial effluent can be much higher (up to 250 μg/L). Genistein, formononetin, biochanin A, daidzein and coumestrol are the most commonly identified phytoestrogens in the aquatic environment, and they have been found in rivers in Australia, Germany and Italy ranging from 1 to 10 ng/L [2,5]. Daidzein and genistein have been detected in river water in Japan at 43 μg/L and 143 μg/L, respectively [6].…”