Hach DR2400 - Page 134

Chloramine (Mono)
Chloramine (Mono)
Page 4 of 6
Chloramine (Mono)_AVPP_High_MCF_Eng_Ody.fm
7. Open an ampule and use a glass Mohr pipet to add the calculated amount of
Chlorine Solution slowly to the ammonia standard, while mixing at medium
speed on a stir-plate.
8. Allow the monochloramine solution to mix for 1 minute after all Chlorine
Solution is added.
9. Quantitatively transfer the monochloramine solution to a clean 100-mL
Class A volumetric flask. Dilute to the mark with organic-free water, cap, and
mix thoroughly. This is a nominal 4.5-mg/L (as Cl
2
) monochloramine
standard.
10. Use this standard within 1 hour of preparation. Analyze according to the Low
Range Monochloramine procedure described above.
11. To adjust the calibration curve using the reading obtained with the 4.5-mg/L
standard solution, touch
Options on the current program menu. Touch
Standard Adjust.
12. Touch
On. Touch Adjust to accept the displayed concentration (the value
depends on the selected chemical form). If an alternate concentration is used,
touch the number in the box to enter the actual concentration, then touch
OK.
Touch
Adjust.
Method Performance
Precision
Standard: 5.0 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
The sample is first diluted in a Test ‘N Tube. In the presence of a cyanoferrate
catalyst, monochloramine (NH
2
Cl) in the sample reacts with a substituted
phenol to form an intermediate monoimine compound. The intermediate
couples with excess substituted phenol to form a green-colored indophenol,
which is proportional to the amount of monochloramine present in the sample.
Test results are measured at 655 nm.
Program 95% Confidence Limits of Distribution
67 4.8–5.2 mg/L Cl
2
Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 0.1 mg/L Cl
2
*
* Use the LR Chloramine (Mono) test for concentrations below 4.5 mg/L Cl
2
.