Isomer-specific determination of 4-nonylphenols using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry.
Technical nonylphenol (tNP), used for industrial production of nonylphenol polyethoxylate surfactants, is a complex mixture of C(3-10)-phenols. The major components, 4-nonylphenols, are weak endocrine disruptors whose estrogenicities vary according to the structure of the branched nonyl group. Thus, accurate risk assessment requires isomer-specific determination of 4-NPs. Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/ToFMS) was used to characterize tNP samples obtained from seven commercial suppliers. Under optimal chromatographic conditions, 153-204 alkylphenol peaks, 59-66 of which were identified as 4-NPs, were detected. The 4-NPs comprised approximately 86-94% of tNP, with 2-NPs and decylphenols making up approximately 2-9% and approximately 2-5%, respectively. The tNP products were analyzed for eight synthetic 4-NP isomers, and results were compared with published data based on GC/MS analysis. Significant differences were found among the products and between two samples from a single supplier. The enhanced resolution of GC x GC coupled with fast mass spectral data acquisition by ToFMS facilitated identification of all major 4-NP isomers and a number of previously unrecognized components. Analysis of tNP altered by the bacterium, Sphingobium xenophagum Bayram, revealed several persistent 4-NPs whose structures and estrogenicities are presently unknown. The potential of this technology for isomer-specific determination of 4-NP isomers in environmental matrices is demonstrated using samples of wastewater-contaminated groundwater and municipal wastewater.
Eganhouse
Robert P
RP
U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, Virginia 20192, USA. eganhous@usgs.gov
Pontolillo
James
J
Gaines
Richard B
RB
Frysinger
Glenn S
GS
Gabriel
Frédéric L P
FL
Kohler
Hans-Peter E
HP
Giger
Walter
W
Barber
Larry B
LB
D001419:Bacteria / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007536:Isomerism; D010636:Phenols / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis; D014881:Water Supply / Q000032:analysis
D010636:Phenols; D012722:Sewage; D014874:Water Pollutants, Chemical; C025256:nonylphenol