Separation, Structural Elucidation and Estrogenic Activity Studies of the Structural Isomers of 4-nonylphenol by Gc-pfc Coupled with Ms and Nmr

A commercial nonylphenol (NP) reagent was separated into 14 fractions, NP1 to NP14 using a gas chromatograph equipped with a preparative fraction collector (GC-PFC). The identifi cation of the major components of 14 fractions was attempted by analysis of their nuclear magnetic resonance (NMR) spectra, and the estrogenicity of the isomers was tested in a recombinant yeast screen system. Eleven structural isomers of NP were characterised and identifi ed as the following para(position 4-) branch isomers of phenol: NP1 1,3-dimethyl-1-propyl-butyl NP2 1,1,3-trimethyl-hexyl NP3 1,4-dimethyl-1-ethyl-pentyl NP4 1,3-dimethyl-1-ethyl-pentyl NP5 1,1,4-trimethyl-hexyl NP6 1,3-dimethyl-1-ethyl-pentyl NP7 1,1-dimethyl-2-ethyl-pentyl NP9 1,2-dimethyl-1-ethyl-pentyl NP10 1,2-dimethyl-1-propyl-butyl NP11 1,1,2-trimethyl-hexyl NP12 1-ethyl-1-methyl-hexyl The three isomers NP8, NP13 and NP14 still remain to be identifi ed. NP7 (4-(1,1-dimethyl-2-ethyl-pentyl)-phenol) was found to exhibit the highest estrogenic activity, corresponding to 1.9×10 that of 17β-estradiol (E2). The relative composition of the NP isomers varied between the dissolved phase and suspended solids separated from a water sample in New York-New Jersey Harbour, USA. The proportions of the isomers in the NP mixture were different from the proportions in the environmental samples. In suspended solids, the NP7 was present in higher proportions than other isomers.