LaMotte DC1600 Colorimeter User Manual
Page 60
PROCEDURE
1.
Rinse a clean colorimeter tube (0967) with sample water. Fill to 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 “Set Blank” knob. This is the 100%T blank.
4.
Remove tube from colorimeter and pour off 5 mL into graduated cylinder (0416). Discard the remaining sample.
5.
Return the 5 mL sample to colorimeter tube. Use the graduated cylinder to measure 5 mL of *Mixed Acid Reagent
(V-6278) and add to tube. Cap and mix. Wait approximately 2 minutes before proceeding to Step 6.
6.
Use the 0.1 g spoon (0699) to add two measures of *Nitrate Reducing Reagent (V-6279). Cap.
7.
Hold tube by index finger and thumb and mix by inverting approximately 50-60 times a minute for four minutes. Wait
10 minutes for maximum color development.
NOTE: At end of waiting period an undissolved portion of Nitrate Reducing Reagent may remain in bottom of the
tube without affecting results.
8.
At end of 10 minute waiting period, press “30 Second Read” button and insert tube into colorimeter chamber. Record
%T as soon as reading stabilizes.
9.
Consult calibration chart to determine nitrate nitrogen concentration in parts per million (ppm).
NOTE: To convert Nitrate Nitrogen (NO
3
–N) results to ppm Nitrate (NO
3
), multiply by 4.4.
DC1600 NITRATE-NITROGEN CALIBRATION CHART
%T
9
8
7
6
5
4
3
2
1
0
90
0.02
0.03
0.05
0.06
0.07
0.08
0.10
0.11
0.12
0.14
80
0.15
0.16
0.18
0.19
0.20
0.22
0.23
0.25
0.26
0.27
70
0.29
0.30
0.32
0.34
0.35
0.37
0.38
0.40
0.42
0.43
60
0.45
0.47
0.48
0.50
0.52
0.54
0.56
0.58
0.60
0.62
50
0.64
0.66
0.68
0.70
0.72
0.74
0.76
0.78
0.81
0.83
40
0.86
0.88
0.90
0.93
0.96
0.98
1.01
1.04
1.07
1.10
30
1.13
1.16
1.19
1.22
1.25
1.29
1.32
1.36
1.40
1.44
20
1.48
1.52
1.56
1.61
1.65
1.70
1.75
1.80
1.86
1.92
10
1.98
2.04
2.11
2.18
2.26
2.34
2.43
2.52
2.63
2.74
0
2.87
3.01
60