Hach DR2400 - Page 320

Iodine
© Hach Company, 2003. All rights reserved. Printed in the U.S.A. 3/04 1ed
Page 4 of 4 Iodine_AVPP_Other_DPD_Eng_Ody.fm
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Sample Collection, Storage and Preservation
Collect samples in clean, dry glass containers. If sampling from a tap, allow the
water to flow at least 5 minutes to ensure a representative sample. Avoid
excessive agitation and exposure to sunlight when sampling. Allow several
volumes of water to overflow the container and cap the container so there is not
headspace above the sample. If sampling with a sample cell, rinse the cell several
times with the sample, then carefully fill to the 10-mL mark. Proceed with the
analysis immediately.
Method Performance
Precision
Standard: 3.83 mg/L I
2
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
Iodine reacts with DPD (N, N-diethyl-p-phenylenediamine) to form a pink color,
the intensity of which is proportional to the total iodine concentration. Test
results are measured at 530 nm.
Required Reagents
Quantity Required
Description per test Unit Cat. No.
DPD Total Chlorine Reagent Powder Pillows......................................1 pillow........... 100/pkg.............21056-69
or
DPD Total Chlorine Reagent AccuVac
®
Ampuls.................................1 ampul........... 25/pkg...............25030-25
Required Apparatus
Beaker, 50-mL............................................................................................1 ....................... each.................... 500-41H
Sample Cells, 10-mL, w/cap...................................................................2 ....................... 6/pkg.................24276-06
Program 95% Confidence Limits of Distribution
240 3.76–3.90 mg/L I
2
242 3.69–3.97 mg/L I
2
Program Portion of Curve ∆Abs ∆Concentration
240 Entire range 0.010 0.07 mg/L I
2
242 Entire range 0.010 0.07 mg/L I
2