Hach DR2400 - Page 446

Nitrate
© Hach Company, 2003. All rights reserved. Printed in the U.S.A. 3/04 1ed
Page 4 of 4 Nitrate_UniCell_Dimeth_Eng_Ody.fm
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Standard Solution Method
Prepare a 6-mg/L NO
3
–N standard solution by pipetting 6 mL of
1000-mg/L NO
3
–N into a 1000-mL volumetric flask. Dilute to the mark with
deionized water. Stopper and invert to mix. Prepare this solution daily. Perform
the nitrate procedure as described above.
Note: Make sure the selected chemical form is NO
3
–N.
Method Performance
Precision
Standard: 5.7 mg/L NO
3
–N
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
Nitrate ions react with 2,6-dimethylphenol in a solution containing sulfuric
and phosphoric acids to form 4-nitro-2,6-dimethylphenol. Measurements are
taken at 370 nm.
Required Reagents
Description Unit Cat. No.
Nitrate - NO
3
, UniCell™ HCT 106................................................................................... 23/pkg.............. HCT 106
Optional Reagents
EDTA Solution .................................................................................................................... 50 mL SCDB .....22419-26
Nitrate Nitrogen Standard Solution, 1000-mg/L as NO
3
–N ....................................... 500 mL...............12792-49
Sodium Hydroxide Standard Solution ............................................................................ 50 mL SCDB .......2450-26
Sulfuric Acid, ACS.............................................................................................................. 500 mL...................979-49
Optional Apparatus
Cylinder, mixing, 100-mL.................................................................................................. each........................508-42
Flask, volumetric, 1000-mL ............................................................................................... each....................14574-53
Pipettor, Jencons, 100–1000 µL.......................................................................................... each....................27949-00
Replacement Tips, for 27949-00 ........................................................................................ 400/pkg.............27950-00
Pipettor, Jencons, 1–5 mL................................................................................................... each....................27951-00
Replacement Tips, for 27951-00 ........................................................................................ 100/pkg.............27952-00
Program 95% Confidence Limits of Distribution
805 5.3–6.1 mg/L NO
3
–N
Program Portion of Curve ∆Abs ∆Concentration
805 Entire range 0.010 0.1 mg/L NO
3
–N