Copper test diethyzdithiocarbamate method – LaMotte DCL-20 Colorimeter User Manual
Page 15
COPPER TEST
DIETHYZDITHIOCARBAMATE METHOD
QUANTITY
CONTENTS
CODE
15 mL
*Copper Reagent
*6446-E
*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.
Like many other micronutrients, the amount of available copper varies considerably with the type of soil. Well drained
sandy soils are usually low in copper while heavily clay-type soils contain an abundant supply of copper. Like manganese,
copper may be unavailable in soils that have a high organic make-up because it readily forms insoluble complexes with
organic compounds.
Generally from 0.2-25 lbs/A of copper is added to the soil to correct a deficient level. Copper is another metal that is
necessary in the formation of the chlorophyll molecule and like other metals, e.g. iron, manganese and zinc acts as a
catalyst.
RANGE:
0-25 ppm
METHOD:
Cu pric ions form a yel low col ored che late with Diethyldithiocarbamate around pH 9-10, in pro por -
tion to the con cen tra tion of cop per in the sam ple.
IN TER FER ENCES:
Bis muth, co balt, mer cury, nickel and sil ver ions and chlo rine (6 ppm or greater) in ter fere se ri ously
and must be ab sent.
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 2 on the “Select Wavelength” knob.
3. Insert tube containing sample into chamber and press the “30 Second Read” button. Adjust “100"%T with the ”Set
Blank" knob.
4. Remove the tube and add 5 drops of *Copper Reagent (6446). Cap and mix contents. A yellow color indicates the
presence of copper.
5. Insert sample into colorimeter chamber, press the “30 Second Read” button and measure %T as soon as reading
stabilizes.
6. Consult chart to find the concentration of Copper in parts per million.
NOTE:
There is a ten dency for the me ter to drift with the use of the blue fil ter (415nm) as a re sult of the photocell’s
re sponse to blue light. For best re sults, af ter sam ple has been in serted into cham ber and cov ered, al low ap -
prox i mately 10 sec onds be fore tak ing the read ing.
COPPER CALIBRATION CHART (PPM)
%T
9
8
7
6
5
4
3
2
1
0
90
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
80
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
70
2.0
2.2
2.3
2.4
2.5
2.6
2.8
2.9
3.0
3.1
60
3.3
3.4
3.5
3.7
3.8
3.9
4.1
4.2
4.4
4.5
50
4.7
4.8
5.0
5.2
5.3
5.5
5.6
5.8
6.0
6.2
40
6.4
6.5
6.7
6.9
7.1
7.3
7.5
7.7
8.0
8.2
30
8.4
8.6
8.9
9.1
9.4
9.6
9.9
10.2
10.5
10.8
20
11.1
11.4
11.7
12.1
12.4
12.8
13.2
13.6
14.0
14.4
10
14.9
15.4
15.9
16.4
17.0
17.6
18.3
19.0
19.8
20.7
0
21.6
22.7
23.9
25.3
COPPER CONCENTRATION CHART
%T
RANGE
PARTS PER MILLION
89-100%
Low
0-1 ppm
71-88%
Marginal
1-3 ppm
63-70%
Adequate
3-4 ppm
15
1985-01 • 10/01