Tannin – LaMotte DC1600 Colorimeter User Manual
Page 85
TANNIN
TUNGSTO-MOLYBDOPHOSPHORIC ACID METHOD
CODE 3666
QUANTITY
CONTENTS
CODE
30 mL
*Tannin Reagent #1
*7833-G
2 x 60 mL
*Tannin Reagent #2
*7834-H
1
Pipet, plain, plastic
0352
1
Pipet, 1.0 mL, plastic
0354
*WARNING: Reagents marked with a * are considered hazardous substances. Material Safety Data Sheets (MSDS) are supplied for
these reagents. For your safety, read label and accompanying MSDS before using.
Tannin and lignin are examples of hydroxylated aromatic compounds found in discharge wastewater from paper mills, in
some boiler water treatment, in natural brackish water, and in wastewater from leather tanning plants. The taste and odor
of these compounds is generally offensive so that their control is important in many areas.
APPLICATION:
Industrial wastewater, boiler water, and natural water.
RANGE:
0 – 10 ppm Tannic Acid
METHOD:
The hydroxylated aromatic compounds will reduce a mixture of tungstophosphoric and
molybdophosphoric acids to form a blue color in proportion to the concentration of aromatic
hydroxyl groups.
SAMPLE HANDLING
& PRESERVATION:
Sample should be analyzed as soon as possible after collection.
INTERFERENCES:
Other reducing compounds such as ferrous iron and sulfites. Results may be expressed as tannin
like compounds, or aromatic hydroxy compounds.
PROCEDURE
1.
Rinse a clean colorimeter tube (0967) with sample water. Fill to the 10 mL line with sample.
2.
Select setting 6 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.
Remove tube from colorimeter. Use the plain pipet (0352) to add 4 drops of *Tannin Reagent #1 (7833). Cap and
mix.
5.
Use the 1.0 mL pipet (0354) to add 2.0 mL of *Tannin Reagent #2 (7834). Cap and mix. Wait 30 minutes for full
color development.
6.
At end of 30 minute waiting period press “30 Second Read” button and insert tube into colorimeter chamber. Record
%T as soon as reading stabilizes.
7.
Consult calibration chart to determine tannic acid or “hydroxylated aromatic compounds” concentration in parts per
million (ppm).
NOTE: It is suggested for best possible results to carry a blank through the procedure to compensate for any color
which may be present in the reagents. Set the reagent blank to 100%T, then continue with unknown sample tests.
DC1600 TANNIN (TANNIC ACID) CALIBRATION CHART
%T
9
8
7
6
5
4
3
2
1
0
90
0.22
0.27
0.32
0.36
0.41
0.46
0.51
0.56
0.61
0.66
80
0.71
0.76
0.81
0.86
0.92
0.97
1.02
1.08
1.13
1.19
70
1.25
1.30
1.36
1.42
1.48
1.54
1.60
1.66
1.73
1.79
60
1.85
1.92
1.99
2.05
2.12
2.19
2.26
2.33
2.40
2.48
50
2.55
2.63
2.71
2.78
2.86
2.95
3.03
3.11
3.20
3.29
40
3.37
3.46
3.56
3.65
3.75
3.85
3.95
4.05
4.16
4.26
30
4.37
4.49
4.60
4.72
4.84
4.97
5.10
5.23
5.37
5.51
20
5.65
5.80
5.96
6.12
6.29
6.46
6.64
6.83
7.03
7.23
10
7.45
7.68
7.92
8.17
8.44
8.72
9.03
9.36
9.71
10.10
85