<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>J. Pontolillo</dc:contributor>
  <dc:contributor>R.B. Gaines</dc:contributor>
  <dc:contributor>G.S. Frysinger</dc:contributor>
  <dc:contributor>F.L.P. Gabriel</dc:contributor>
  <dc:contributor>H.-P.E. Kohler</dc:contributor>
  <dc:contributor>W. Giger</dc:contributor>
  <dc:contributor>L. B. Barber</dc:contributor>
  <dc:creator>R.P. Eganhouse</dc:creator>
  <dc:date>2009</dc:date>
  <dc:description>&lt;div class="hlFld-Abstract"&gt;&lt;div id="abstractBox"&gt;&lt;p class="articleBody_abstractText"&gt;Technical nonylphenol (tNP), used for industrial production of nonylphenol polyethoxylate surfactants, is a complex mixture of C&lt;sub&gt;3−10&lt;/sub&gt;-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 × 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 ∼86−94% of tNP, with 2-NPs and decylphenols making up ∼2−9% and ∼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 × 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,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Sphingobium xenophagum&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;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.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;div class="hlFld-Fulltext"&gt;&lt;br data-mce-bogus="1"&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/es902622r</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>ACS</dc:publisher>
  <dc:title>Isomer-specific determination of 4-nonylphenols using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>