<?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>Paul M. Gates</dc:contributor>
  <dc:creator>W.T. Foreman</dc:creator>
  <dc:date>1997</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Analysis of&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDT in environmental samples requires monitoring the GC-derived breakdown of this insecticide, which produces&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDD and/or&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDE, both also primary environmental degradation products. A performance evaluation standard (PES) containing&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDT but not&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDD or&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDE can be injected at regular intervals throughout an analytical sequence to monitor GC degradation. Some U.S. EPA methods limit GC breakdown of DDT in the PES to &amp;le;20%. GC/MS analysis of large-volume natural water samples fortified with deuterium- and&amp;nbsp;&lt;/span&gt;&lt;span&gt;13&lt;/span&gt;&lt;span&gt;C-labeled&amp;nbsp;&lt;/span&gt;&lt;i&gt;p,p&lt;/i&gt;&lt;span&gt;&amp;lsquo;-DDT exhibited up to 65% DDT breakdown by the GC inlet. These matrix-enhanced GC degradation amounts substantially exceeded the &amp;lt;20% breakdown levels indicated by bracketing injections of the PES containing unlabeled and labeled DDT. Substantial matrix-enhanced GC degradation was not observed during analysis of a limited number of fractionated bed-sediment extracts containing labeled DDT. Use of isotopically labeled DDT seems to provide an effective tool for monitoring sample-specific DDT breakdown during GC/MS analysis. However, analyte co-elutions render impractical their use in GC/ECD analysis. The oc currence of matrix-enhanced GC degradation might have important implications on data quality and the resultant interpretations of the environmental degradation of DDT and other thermolabile contaminants.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/es960671q</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>ACS Publications</dc:publisher>
  <dc:title>Matrix-enhanced degradation of p,p'-DDT during gas chromatographic analysis: A consideration</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>