Manganese test - periodate method – LaMotte DCL-20 Colorimeter User Manual
Page 17
MANGANESE TEST - PERIODATE METHOD
QUANTITY
CONTENTS
CODE
10 g
Manganese Buffer Reagent
6310-D
15 g
*Manganese Periodate Reagent
*6311-E
2
Spoon, 0.1 g
0699
The amount of manganese available to the plant is dependant upon the soil pH, the quantity of organic matter present, and
the degree of aeration. Manganese deficiency is most likely to occur in neutral or alkaline soils because it is less soluble at
elevated pH levels. In extremely acid soils, where manganese is more soluble, toxic levels may exist which may reduce crop
yields. In slightly acid sandy soils, manganese may leach past the root zone and not be able for utilization by the plant. Also,
it is believed that manganese may form insoluble organic complexes in some soils that have high humus content. All of the
factors contribute to the availability of this essential element. Only soil or tissue tests can determine whether deficient or
toxic levels of manganese exist.
Although manganese is known to play an important role in many of the metabolic processes in the plant, little is known
about its function other than it is required in some enzyme reactions and is required for the formation of chlorophyll in the
plant.
RANGE:
0-100 ppm
METHOD:
Periodate method.
IN TER FER ENCES:
Re ducing sub stances ca pa ble of re act ing with periodate or per manga nate must be elim i nated. Chlo -
rine in small amounts can be ox i dized by periodate.
PROCEDURE
1. Fill a clean colorimeter tube (0967) to the 10 mL line with the soil filtrate then neutralize according to the procedure
on page 10.
2. Select setting 4 on the “Select Wavelength” knob.
3. Insert tube containing sample into chamber and press the “30 Second Read” button. Adjust to “100"%T with the ”Set
Blank" knob.
4. Remove the tube and add two level measures of Manganese Buffer Reagent (6310) with the 0.1 g spoon (0699). Cap
and mix to dissolve the powder.
5. With the other 0.1 g spoon (0699), add one heaping measure of *Manganese Periodate Reagent (6311) to the contents
of the tube, cap and mix. An undissolved portion of the reagents may remain in the bottom of the tube without
adversely affecting the results.
6. Allow approximately two minutes for the pink color to develop if manganese is present.
7. Insert test sample into colorimeter chamber, press the “30 Second Read” button, and measure %T as soon as reading
stabilizes.
8. Consult chart to find the concentration of Manganese in parts per million (ppm).
MANGANESE CALIBRATION CHART (PPM)
%T
9
8
7
6
5
4
3
2
1
0
90
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
80
3.6
4.0
4.5
4.9
5.3
5.8
6.2
6.7
7.1
7.6
70
8.0
8.5
9.0
9.5
9.9
10.4
10.9
11.4
12.0
12.5
60
13.0
13.5
14.1
14.6
15.2
15.7
16.3
16.9
17.5
18.1
50
18.7
19.3
19.9
20.6
21.2
21.9
22.6
23.2
23.9
24.6
40
25.4
26.1
26.8
27.6
28.4
29.2
30.0
30.8
31.7
32.5
30
33.4
34.3
35.3
36.2
37.2
38.2
39.2
40.3
41.4
42.5
20
43.7
44.9
46.1
47.4
48.7
50.1
51.5
53.0
54.6
56.2
10
57.9
59.7
61.6
63.6
65.7
67.9
70.3
72.8
75.6
78.6
0
81.9
85.5
89.6
94.3
99.7
17
1985-01 • 10/01