NYC-WTC_000182790

NYC 9/11 Public Portal Document

Pace Analytical Servises, Inc. 1700 Elm Strset. Suite 200 .J^ace Analytical" Minneapolis, MN 55414 Phone: 612.607.1700 www.pacelabs.com REPORT OF: CHEMICAL ANALYSES Fax: 612.607.6444

PROJECT; PCDD/PCDF ANALYSES DATE: December 3, 2001

PAGE: 4 REPORT NO: 01-1051099

PCDD/PCDF Quantification and Calculations

The PCDD/PCDF isomers were quantified by comparison of their responses to the responses of the labeled internal standards. Relative response factors were calculated from analyses of standard mixtures containing representatives of each of the PCDD/PCDF congener classes at five concentration levels, and each of the internal standards at one concentration level, as shown in Table 4. The PCDD/PCDF response factors were calculated by comparing the sum of the responses from the two ion masses monitored for each chlorine congener class to the sum of the responses from the two ion masses of the corresponding isotopically labeled internal standard. The formula for the response factor calculation is:

An X Qis Rf = Ais X Qn

where:

Rf = Response factor An = Sum of integrated areas for native isomer Qis = Quantity of labeled internal standard Ais = Sum of integrated areas for labeled internal standard Qn = Quantity of native isomer

The levels of PCDD/PCDF in each sample were quantified using the following equation:

An X Qis C = Ais X W X Rf where:

C = Concentration of target isomer or congener class An = Sum of integrated areas for the target isomer or congener class Qis = Quantity of labeled internal standard added to the sample Ais = Sum of integrated areas for the labeled internal standard W = Sample amount Rf = Response factor

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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NYC-WTC_000182794