Hach DR/850, Procedures Manual, Page: 89 / 460

89
Summary of Method
In the presence of a cyanoferrate catalyst, monochloramine 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.
Instrument Setup
This procedure will add the current method as a new Hach
program to your DR/850 or DR/890.
1. Turn on the instrument by pressing the
ON
key.
2. Press the
SETUP
key.
3. Press the down arrow key until the prompt line shows
USER
.
4. Press the
ENTER
key.
5. Enter
8138
, followed by
ENTER
.
6. Enter each of the numbers in the right column, each followed
by
ENTER
. The line numbers in the left column relate to the
line number on the display. At any time, you may use the
arrow keys to scroll back to review or change a number
already entered.
Sample Temperature
Minutes
° C ° F
5 40 10
7 42 9
9 48 8
10 50 8
12 54 7
14 58 7
16 61 6
18 68 4
20 73 3
23 75 2.5
25 77 2
>25 >77 2
CHLORAMINE, MONO, Low Range, continued