Polyphenolic compounds, both anthropogenic and naturally occurring, are ubiquitous throughout the environment. While many of these compounds have been shown to have an endocrine disruptor effect, others are touted for their health promoting benefits. Phytoestrogens such as quercetin have received considerable attention as antioxidants and anticarcinogens. Estimating the potential for benefit or harm from a natural or synthetic estrogenic phenol requires elucidation of the chemical and physiological mechanisms involved, including an understanding of the interaction between the compound and the receptor site on the target cell. This, in turn, requires rapid analytical techniques capable of positively identifying a large number of structurally similar compounds. In this paper, we report on analytical investigations of polyphenolics focusing on quercetin, a naturally occurring flavonol.