NYC-WTC_000226903

NYC 9/11 Public Portal Document

4? pi Pace Analytical Services, Inc. 1700.Elm Street, Suite 200 'ace Analytical' yi'i Minneapolis, MH 55414 Phone: 612.607.1700 www.pacelabs.com REPORT OF: CHEMICAL ANALYSES Fax: 612.607.6444

PROJECT: PCDD/PCDF ANALYSES DATE: January 9, 2002'

PAGE: 7 REPORT NO: 01-1052682 ')•

RESULTS 17?

The results from5the analyses are presented in the following:

Appendix A - Documentation _ ^..^^Appendix B - PCDD/PCDF Analysis Results

.s 7 .; DISCUSSION n Ii The recoveries of the isotopically-labeled PCDD/PCDF internal standards in the sample extracts ^" ranged from 72-124% and indicate a level of efficiency through the extraction and enrichment ■ s

steps that is considered typical for this matrix. All of the internal standard recoveries for the field samples were within the target limits for this method. Also, since the quantifications of the native r7 2,3,7,8-substituted isomers were based on isotope dilution, the data were automatically corrected for variation in recovery and accurate values were obtained.

A laboratory method blank was prepared and analyzed with the sample batch as part of our routine quality control procedures. .The results^ found at the beginning of Appendix B, show the blank to be free of PCDDs and PCDFs. This suggests that the sample processing steps did not impact the results of the analyses.

(ikS Laboratory spike samples were also prepared with the sample batch by extracting a clean wipe that- had been fortified with native standard materials. The results, found at the end of Appendix B, show that the spiked native. compounds vyere recovered at 96-115% with relative percent differences of 1.0-8.7%. This indicates high degrees of accuracy and precision for, these determinations.

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REPORT OF LABORATORY ANALYSIS This report shall not be reproduced, except in full, without the written consent of Pace Analytical Services, Inc.

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