LaMotte DC1600 Colorimeter User Manual
Page 20
PROCEDURE
A. BROMINE (NO CHLORINE)
1.
Rinse a clean colorimeter tube (0967) with sample water. Fill to the 10 mL line with sample.
2.
Select setting 4 on “Select Wavelength” knob and press the “30 Second Read” button.
3.
Insert tube into colorimeter chamber and adjust to 100%T with the “Set Blank” knob. This is the 100%T blank.
4.
Remove tube from the colorimeter. Pour out all but a sufficient amount of sample water to cover a tablet. Add one
*DPD #1 Instrument Grade Tablet (6903). Crush tablet with tablet crusher (0175), then add sample water until tube
is filled to 10 mL line. Cap tube and shake until tablet is dissolved. Solution will turn pink if bromine is present.
5.
Press “30 Second Read” button and insert tube into colorimeter chamber. Record %T as soon as reading stabilizes.
6.
Consult calibration chart to determine bromine concentration in parts per million (ppm).
B. BROMINE IN THE PRESENCE OF CHLORINE
1.
Rinse a clean colorimeter tube (0967) with sample water. Fill to the 10 mL line with sample.
2.
Select setting 4 on “Select Wavelength” knob and press “30 Second Read” button.
3.
Insert tube into colorimeter chamber and adjust to “100”%T with the “Set Blank” knob. This is the 100%T blank.
4.
Rinse a second clean colorimeter tube (0967) with sample water. Fill to the 10 mL line with sample. Add 5 drops of
Glycine Solution (6811). Cap and mix.
5.
Remove 100%T blank from colorimeter. Pour out all of the sample water. To this tube add just enough of Glycine
treated sample (Step 4) to cover a tablet. Add one *DPD#1 Instrument Grade Tablet (6903). Crush tablet with a
tablet crusher (0175). Add all remaining Glycine-treated sample. Cap tube and shake until tablet dissolves. Solution
will turn pink if bromine is present.
6.
Press “30 Second Read” button, and insert sample into colorimeter chamber. Record %T as soon as reading stabilizes.
7.
Consult calibration chart to determine bromine concentration in parts per million (ppm). Record as Reading BR.
C. FREE AVAILABLE, TOTAL AVAILABLE AND
COMBINED CHLORINE IN THE PRESENCE OF BROMINE
NOTE: Combined chlorine is not affected by the presence of bromine, so the calculation is the same as when
only chlorine is present.
1.
Perform the test for free and combined chlorine as previously described.
2.
Perform the test for bromine in the presence of chlorine.
3.
Calculations:
Residual Bromine (ppm) = Reading BR
Free Chlorine in the Presence of Bromine = Free Chlorine
−
0.45 (Reading BR)
Total Chlorine in the Presence of Bromine = Total Chlorine
−
0.45 (Reading BR)
Combined Chlorine in the Presence of Bromine = Total Chlorine
−
Free Chlorine
DC1600 BROMINE CALIBRATION CHART
%T
9
8
7
6
5
4
3
2
1
0
90
0.10
0.12
0.13
0.15
0.17
0.19
0.21
0.23
0.25
0.27
80
0.29
0.31
0.33
0.35
0.37
0.40
0.42
0.44
0.47
0.49
70
0.51
0.54
0.56
0.59
0.61
0.64
0.67
0.69
0.72
0.75
60
0.78
0.81
0.84
0.87
0.90
0.93
0.96
1.00
1.03
1.06
50
1.10
1.14
1.17
1.21
1.25
1.29
1.33
1.37
1.42
1.46
40
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.86
1.91
1.97
30
2.03
2.09
2.16
2.23
2.30
2.37
2.44
2.52
2.60
2.68
20
2.77
2.86
2.96
3.06
3.16
3.27
3.39
3.51
3.64
3.78
10
3.93
4.08
4.25
4.43
4.63
4.84
5.07
5.32
5.60
5.92
0
6.27
6.67
7.14
7.70
8.38
9.24
10.40
20