Alevel biology practical write up is a report of a laboratory experiment conducted by students. It is required as part of the assessment for the subject.
The a-level biology practical write up document is a professional report and should be organised in a clear and logical manner. It should inc...
Vitamin C
To measure the Vitamin C content in different fruit juices
Hypothesis:
As the concentration of vitamin C increases, the volume of DCPIP required decreases.
Vitamin C is an antioxidant that is vital in bone, skin and blood formation and their maintenance. It is
water soluble; the body does not store it and therefore requires a regular supply of water soluble
vitamins in order to maintain adequate levels. It is a naturally occurring vitamin in fruits and
vegetables.[1] Vitamin C antioxidant activity may help reduce inflammation and lower the possible risk
of various conditions forming as it helps remove unwanted reactive oxidative substances. It is also
vital to produce collagen for the fibrous tissues in the body.[2]
When vitamin C reacts with DCPIP, it causes a colour change of blue to colourless.
Equipment:
● 1% DCPIP solution
● 1% vitamin C Solution
● A range of fruit Juices
● Conical flask
● Pipette
● Burette with clamp stand and clamp
Variables:
● Dependent-volume of juice required to decolourise 1cm3 of DCPIP
● Independent-type of fruit juice used
● Control- volume of DCPIP, same end point colour
Risk Assessment:
➔ Probability/severity of risk: 1-Low, 2-Medium, 3-High/Likely
➔ Total Risk: 1, 2, 3, 4, 6, 9
Risk: Hazard: Probability: Severity: Total Risk: Precaution:
DCPIP Irritant to eyes 2 2 4 Wear eye protection and
and skin gloves;wash hands
thoroughly after use
Broken glass Cuts to skin 1 1 2 Ensure equipment away
from from sharp from table edges;take
equipment edges care when handling
equipment
Method:
1. Set up the clamp stand and place the burette in the clamp-ensure the tap is closed.
2. Pipette 1cm3 of 1% DCPIP solution into a conical flask.
3. Fill the burette with 1% vitamin C solution and record the starting value.
4. Use the burette to slowly add the Vitamin C solution to the DCPIP Solution drop
by drop
5. After adding each drop,shake the conical flask gently.
6. Close the tap as soon as the DCPIP decolourises and note the end value.
7. Calculate amount of Vitamin C solution that was required(initial-end).
8. Repeat the procedure with other types of fruit Juices.
, Practical 2
Results:
Type of Fruit Start volume End volume Difference
Juice: of Fruit of Fruit Juice in Volume
juice(cm3) (cm3) (cm3)
Vitamin C 1% 50.0 45.0 5.0
Solution
(Control)
Fruit Juice A: 50.0 42.7 7.3
0.08%
50.0 42.7 7.3
50.0 42.6 7.4
Fruit Juice B: 50. 0 42 8.0
0.06%
50.0 41.8 8.2
50.0 42.6 7.4
Fruit Juice C: 50.0 38 12.0
0.04%
50.0 37.5 11.5
50.0 37.6 11.4
Mean value for each fruit juice:
A- 7.3
B- 7.9
C- 11.6
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