LaMotte DC1600 Colorimeter User Manual
Page 54
PROCEDURE
1.
Suspend the resin column (1079) in the test tube (0608).
2.
Use Demineralizer Bottle (1151) to add 3-4 mL of deionized water to resin column.
3.
Add 5 mL of sample water to resin column with the 1.0 mL pipet (0354). Discard all of the solution that has passed
through resin column.
4.
Continue adding sample water to resin column and collect 10 mL of filtrate in a clean colorimeter tube (0967).
5.
Dip end of plastic rod (0519) in sample water recovered from resin column. Touch it to a small piece (1/4 inch) of
pHydrion paper (2953). Read pH immediately from color chart. Add *Sodium Hydroxide 0.2N (5168) to sample one
drop at a time with stirring. Check pH with a new piece of pHydrion paper after each drop. Continue adjustment until
pH is between 5.5 and 6.5 (preferably 5.5).
NOTE: If pH changes to greater than 7.5 after addition of first drop of *Sodium Hydroxide 0.2N, discard sample and
begin again with Step 1. Step 5, pH adjustment, will not be necessary.
6.
Select setting 1 on “Select Wavelength” knob and press “30 Second Read” button.
7.
Insert tube into colorimeter chamber and adjust to 100%T with “Set Blank” knob. This is the 100%T blank.
8.
Remove tube from colorimeter. Use the 1.0 mL pipet (0354) to add 1.0 mL of pH 7.0 Buffer (2881). Cap and mix.
9.
Use the 0.1 g spoon (0699) to add one measure of *Tiron Powder (6045). Cap and mix until powder dissolves.
Solution will immediately turn yellow if molybdenum is present.
10. Insert tube into colorimeter chamber and press “30 Second Read” button. Record %T as soon as reading stabilizes.
11. Consult calibration chart to determine molybdenum concentration in parts per million (ppm).
DC1600 MOLYBDENUM CALIBRATION CHART
%T
9
8
7
6
5
4
3
2
1
0
90
0.02
0.07
0.11
0.16
0.21
0.26
0.31
0.36
0.41
80
0.46
0.51
0.56
0.61
0.66
0.72
0.77
0.83
0.88
0.94
70
0.99
1.05
1.11
1.17
1.23
1.29
1.35
1.41
1.47
1.53
60
1.60
1.66
1.73
1.80
1.86
1.93
2.00
2.07
2.14
2.22
50
2.29
2.36
2.44
2.52
2.60
2.68
2.76
2.84
2.93
3.01
40
3.10
3.19
3.28
3.37
3.47
3.56
3.66
3.76
3.87
3.97
30
4.08
4.19
4.30
4.42
4.54
4.66
4.78
4.91
5.05
5.18
20
5.32
5.47
5.62
5.77
5.94
6.10
6.28
6.46
6.65
6.84
10
7.05
7.26
7.49
7.73
7.99
8.26
8.55
8.86
9.19
9.55
0
9.95
54