Hach DR2400 - Page 184

Chlorine, Free
© Hach Company, 2003. All rights reserved. Printed in the U.S.A. 3/04 1ed
Page 4 of 4 ChlorineFre_TNT_Other_DPD_Eng_Ody.fm
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3. Snap the neck off a HR Chlorine PourRite
®
Ampule Standard,
50–75 mg/L Cl
2
.
4. Use the TenSette
®
Pipet to add 0.1 mL to a 10-mL sample. Mix thoroughly.
5. Analyze the standard addition sample as described in the procedure above.
Accept each standard additions reading by touching
Read. Each addition
should reflect approximately 100% recovery.
See Section 3.2.2 Standard Additions on page 32 for more information.
Method Performance
Precision
Standard: 2.33 mg/L CL
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
Chlorine in the sample as hypochlorous acid or hypochlorite ion (free chlorine or
free available chlorine) immediately reacts with DPD (N,N-diethyl-p-
phenylenediamine) indicator to form a pink color which is proportional to the
chlorine concentration. Test results are measured at 530 nm.
Required Reagents
Quantity Required
Description per test Unit Cat. No.
Test ‘N Tube™ DPD Free Chlorine Reagent.........................................1 vial ............... 50/pkg...............21055-45
Required Apparatus
Adapter, 16-mm Cell ................................................................................1 ....................... each....................59457-00
Kimwipes...................................................................................................4....................... 280/pkg.............20970-00
Required Standards
Chlorine Standard Solution, 2-mL PourRite
®
Ampule, 50–75 mg/L ......................... 20/pkg...............14268-20
Program 95% Confidence Limits of Distribution
89 2.18–2.48 mg/L Cl
2
Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 0.09 mg/L Cl
2