|Distilled Water||26- 2 Liter plastic soda bottles||Spectrophotometer (optional)|
|Copper Sulfate (CuSO4)- 0.1M, 0.05M, 0.025M||Cork Borer||Cuvettes (optional)|
|Copper Test Kit (enough for 50 tests)||3-1 Liter volumetric flasks||Digital pH tester (optional)|
|1 M HCl||Potting soil||Microwave|
|Seeds (lettuce, radish, mustard, etc.)|
|Paper towel squares (as a filter) and full sheets of paper towels|
|Plastic disposable or glass pipettes with bulb|
|Mortar and pestle|
|10 and 100 mL graduated cylinders|
2. Make stock solutions of 0.1M CuSO4, 0.05M CuSO4
and 0.025M CuSO4. For 0.1 M, add
15.96 g CuSO4 and fill with distilled water to the 1 Liter mark on the volumetric flask. Use
the same procedure for 0.05 M by adding 7.98 g CuSO4 and for 0.025 M by adding 3.99 g
and filling the 1 Liter volumetric flasks with the distilled water to the line.
3. Prepare 26 growth chambers by cutting off the top third of each plastic
bottle. The top piece
is then inverted, placed on top of the chamber and taped to the base. Heat a cork borer and
use it to punch a 1 centimeter port hole in the bottle approximately 1 inch above the bottom of
the bottle The port hole will serve to remove water samples.
4. Add equal amounts of soil to each growth chamber. Be sure to consider
chambers using only regular potting soil (without plants) and autoclaved soil (without
plants). Seedlings should have grown into paper towel. Cut small squares containing 25 seedlings each and plant in the growth chambers,. Use 3 growth chambers for each of the three types of seeds: lettuce, radish and mustard. In the remaining bottles, set up 9 chambers with regular soil, 6 with autoclaved soil and 2 with paper towel (no soil). This will make a total of 26 chambers.
5. Allow the seedlings to grow in soil for three days. The first day,
add 50 mL distilled water
to all of the growth chambers. The second day, water one set of bottles (1 mustard plant, 1
radish, 1 lettuce, 2 autoclaved, 2 plain soil ) with 50 mL of .1M CuSO4, the second set with
50 mL of 0.05M CuSO4 and the third set with 50 mL of 0.025M CuSO4. As an additional
control, water 3 bottles containing regular soil and two bottles with paper towel only with distilled
water each time the other chambers are watered.
6. The third day, water one set of bottles (1 mustard plant, 1 radish, 1 lettuce, 2 autoclaved,
2 plain soil ) with 50 mL of 0.1M CuSO4, the second set with 50 mL of 0.05M CuSO4 and
the third set with 50 mL of 0.025M CuSO4. Also, water the 3 bottles containing plain soil and two bottles with paper towel
and no soil with distilled water as controls. Repeat the overall watering process for a total of four times or 200 mL of
7. On the fourth day, remove a small sample of the filtrate (water which
has drained through the
soil), dilute to 1000 mL and test for copper using the test kit. Compare with the quantity of copper found in the stock
solutions . Stock solutions will need to be similarly diluted. All solutions are diluted to permit testing in the range of the
copper test kit.
8. The results obtained from the copper test are in mg/L or parts per
million (ppm). The copper test kit utilized is a color
comparison test; therefore results may vary.
To convert the Molar solutions used to water the plants,
use the following:
Example: For 0.1M CuSO4 has a molecular weight of 159.6 g/m:
0.1M CuSO4 * 63 g Cu (CuSO4)
* 1000 mg = 6300 mg/L or 6300 ppm
Liter mole gram
9. To determine the amount of copper in the plants, remove the plants
from the soil and dehydrate them in a microwave for 5
minutes. CAUTION: Watch them as they dehydrate because the plants may combust. Remove the plants, mass them, and
10. Place each dried plant sample in a 5 mL of a 1M solution of
HCl. Grind the plants in the solution using the mortar and
pestle. CAUTION: Be careful not to slosh HCl while grinding the plant material. Let it set overnight in a glass container.
11. The next day take 1 mL of the HCl/plant solution to 100 mL distilled water. Use the copper test kit on the sample.
12. Record and graph results.
Graph 1: Filtrate copper concentrations: