NYC-WTC_000226903

NYC 9/11 Public Portal Document

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Pace Analytical Services, Inc. 1700 Elm Street,-.5^16:200 weAnalyticar O . Minneapolis, MN 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: 5 REPORT NO: 01-1052682

® PCDD/PCDF Quantification and Calculations (Cont.) Each pair of ion rnasstpeaks in the selected-ion-current chromatograms was evaluated manually to 54 determine if it rrietifhe criteria for a PCDD or PCDF isomer. Areas of all peaks exhibiting correct ion ratios, having./ijetention times within the correct windows, and having areas corresponding to concentratiohs in the range covered by the initial calibration were then summed for calculations of r? total congener concentrations. The toxic equivalence of each sample was calculated using the factors;1isted in Table 5.

^ r.A'Timit of detection (LOD) based on producing a signal that is 2.5 times the noise level, was calculated for each undetected 2?3,7,8-substituted isomer oL any tetra through octa chlorinated congener class. The noise heights used to calculate the detection limits were measured at the retention time of the specific isomer. The formula used for calculating the LOD is:

Hn X Qis X 2.5 LOD = His X W X Rf. where: • 3 LOD = Single isomer limit of detection Hn = Sum of noise heights at native isomer retention time rl Qis = Quantity of labeled internal standard His Sum of peak heights for labeled internal standard W Sample amount .Response factor

, . The recovery of the 2,3,7,8-TCbD-5 ’Cl4 enrichment efficiency standard and each ’^Cij-labeled j internal standard, relative to either 1,2,3,4-TCDD-''5C,2 or 1,2,3,7,8,9-HxCDD-' “C.,2/ was calculated using the following equation:

I %R = Ais X Qrs x 100%

Rfr X Ars x Qis a where: o

, %R = Percent recovery of labeled internal standard ! Ais = Sum of integrated areas of labeled internal standard ' Qrs = Quantity of recovery standard . Ars Sum of integrated areas of recovery standard i Rfr = Response factor of the specific labeled internal standard relative to the recovery standard'^ " Qis = Quantity of the labeled internal standard congener added to the sample

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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