A study of 14 flavonoids, monohydroxy- to pentahydroxy-substituted, has been carried out using electrospray ionization coupled with high performance liquid chromatography and tandem mass spectrometry. The flavonoids are of increasing interest due to their biological activity and, in particular, those isoflavones that are phytoestrogens. This study is presented in two parts. First, the product ion mass spectra of [M - H](-) of the 14 flavonoids and of [M + H](+) of naringenin and galangin are discussed broadly in terms of five common fragmentation processes. Second, the identification of genistein in wood pulp, in untreated waste water, and in treated (or final) effluent from a wood pulp mill is described. (C) 2001 Elsevier Science B.V.
