Turbidity – LaMotte DC1600 Colorimeter User Manual
Page 87
TURBIDITY
ABSORPTION METHOD
NO REAGENTS REQUIRED
PROCEDURE
1.
Rinse a clean colorimeter tube (0967) with deionized water (turbidity free). Fill to the 10 mL line with deionized
water.
2.
Select setting 1 on “Select Wavelength” knob and press “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.
Rinse a second clean colorimeter tube (0967) with sample water. Fill to the 10 mL line with sample. Cap tube. Wipe
off excess water and fingerprints. Shake to resuspend particulate matter. Remove all bubbles before measurement.
5.
Press “30 Second Read” button and insert tube into colorimeter chamber. Record %T as soon as reading stabilizes.
Turbidity measurements should be taken as soon as possible after sample has been collected.
6.
Consult calibration chart to determine turbidity expressed in Formazin Turbidity Units (FTU).
DC1600 TURBIDITY CALIBRATION CHART (F.T.U.)
%T
9
8
7
6
5
4
3
2
1
0
90
7.0
7.8
8.6
9.4
10.2
11.1
12.0
12.9
13.8
14.7
80
15.7
16.7
17.7
18.7
19.8
20.8
21.9
23.1
24.2
25.4
70
26.6
27.8
29.1
30.4
31.7
33.1
34.5
35.9
37.4
38.9
60
40.4
42.0
43.6
45.3
47.0
48.7
50.5
52.4
54.3
56.2
50
58.3
60.3
62.5
64.7
66.9
69.3
71.7
74.1
76.7
79.3
40
82.1
84.9
87.8
90.8
94.0
97.2
100.5
104.0
107.6
111.4
30
115.3
119.3
123.5
127.9
132.5
137.3
142.3
147.5
153.0
158.7
20
164.8
171.1
177.8
184.8
192.3
200.2
208.6
217.5
227.0
237.1
10
248.0
259.7
272.3
286.0
301.0
317.3
335.3
355.2
377.5
402.6
0
NOTE:
The turbidity calibration chart was prepared by using standard formazin solutions as a reference. These solutions
can be prepared by carefully following the procedure below.†
A.
Dissolve 1.000 g of Hydrazine Sulfate in deionized water and dilute to mark in 100 mL volumetric flask.
B.
Dissolve 10.00 g of Hexamethylenetetramine in deionized water and dilute to mark in 100 mL volumetric flask.
C.
Mix 5 mL of each solution in a 100 mL volumetric flask and allow to set undisturbed for 24 hours.
D.
At the end of the waiting period, dilute to mark with deionized water and mix.
E.
The turbidity of the stock solution is 400 FTU. The stock solution is stable for one month. Dilutions from the
stock should be prepared fresh daily.
†Alternatively, a prepared concentrated formazin standard of 4000 NTU may be ordered in a 60 mL size by Code 6195-H.
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