• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Measurement of the vitamin C content of fruit juices

Extracts from this document...


James Hobbs 10IP Measurement of the vitamin C content of fruit juices Plan: Aim: To investigate the effect of heating on the concentration of vitamin C in fruit juice. Introduction: DCPIP is a purple dye that is decolourised by adding vitamin C or a fruit juice that contains vitamin C. If a standard solution of DCPIP is used then the vitamin C content of different fruit juices can be compared, the more juice it takes to decolourise a standard of DCPIP than the smaller the concentration of the vitamin C in the juice. If the DCPIP solution is first tested with a known concentration of Vitamin C (ascorbic acid) then it is possible to calculate the vitamin C content of other juices. Vitamin C is found in foods such as oranges, lemons, grapefruits, tomatoes, fresh green vegetables and potatoes. A lack of vitamin C causes a disease known as scurvy. The symptoms of this are; Fibres in connective tissue of skin and blood vessels do not form properly, leading to bleeding under the skin, particularly at the joints, swollen, bleeding gums and poor healing of wounds. Vitamin C cannot be stored in the body, so there needs to be a daily intake of vitamin C. Vitamins are group of organic substances quite unrelated to each other in their chemical structure. ...read more.


I.e. you have added 0.6 cm�. Safe Test: Do not carry the syringe around the room. Hold the syringe with the needle pointing down. Wear safety goggles at all times. If the syringe appears blocked, do not force it. Prediction: I thick that the longer the vitamin C is heated the more solution it will take for the DCPIP to decolourise. Observing Time the fruit juice was boiled for (Hours) Vitamin C added -Test 1 (cm�) Vitamin C added -Test 2 (cm�) Vitamin C added -Test 3 (cm�) Vitamin C added -Average (cm�) Standard solution - 0.9 0.95 0.9 0.92 A Fresh 1.0 1.0 - 1.0 B 1/2 hour 1.08 1.1 - 1.09 C 1 hour 1.15 1.12 - 1.14 D 2 hours 1.5 1.4 - 1.45 E 5 hours 2.25 2.2 - 2.23 Analysis I took the averages of my results and used them in the equation mentioned earlier. Percentage of Vitamin C = Average volume of vitamin C used x 0.1 in fruit juice Average volume of fruit juice used Percentage of Vitamin C = 0.92 x 0.1 in fruit juice A 1.0 = 0.092 = 0.09% Percentage of Vitamin C = 0.92 x 0.1 in fruit juice B 1.09 = 0.084403669 = 0.08% Percentage of Vitamin C = 0.92 x 0.1 in fruit juice C 1.14 = 0.080701754 = 0.08% Percentage of Vitamin C = 0.92 x 0.1 ...read more.


I had one anomalous result, the test of fruit juice B. The amount of vitamin C added should have been about 0.12 cm� instead of the 0.09 cm� that I got. This means I did not put enough fruit juice into the DCPIP, which shows a human error as I said before. This was the only anomaly, which shows the results were quite accurate, but also points out the importance of repeating the experiment three times, so that you can see any anomalies. As I said before, you could use a more precise syringe to get more accurate results. Also the more times you repeat the experiment the more accurate the experiment, which means the more accurate the results. Ensure that the Standard solution is tested well as that result effects the end overall results. Another experiment, which could be done, is; to compare the vitamin C contents of Oranges, Lemons and grapefruits, to see which one had the highest amount of vitamin C. The method would be: * Draw up 2 cm� fresh orange juice into a syringe. Add this drop by drop to 1 cm� of DCPIP solution. * Record how much was added and repeat the experiment to obtain averages. * Repeat the experiment with orange and grape fruit juices * Compare the results of all three samples. The one, which uses the least amount of juice, contains the most vitamin C in the juice. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Living Things in their Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

3 star(s)

A fairly good account but more detail need in places and errors made in display of results.

Marked by teacher Adam Roberts 16/07/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Living Things in their Environment essays

  1. Marked by a teacher

    Taxonomy is the branch of biology that deals with the identification and naming of ...

    5 star(s)

    They can be classified according to the way they reproduce. For example some fungi reproduce through spore formation and the dispersal of these spores. Fungi can produce spores either asexually or when two fungal cells fuse and share DNA. Spores are kind of like seeds in that they can be

  2. Marked by a teacher

    A2 Biology Coursework -Investigation into the effect of different concentrations of antibiotics on the ...

    4 star(s)

    with a hand wash * I wore a Lab coat * I wiped the table with a disinfectant to reduce contamination by killing any bacteria on the surface * I made sure that the apparatus I used was capable of carrying a certain amount of solution to reduce the risk

  1. Marked by a teacher

    An Investigation into a Woodlice's Preferred Choice of Environment.

    3 star(s)

    I will need to mark the woodlice in order to do this. I have chosen to put a small white dot on the back of the normal woodlice and two dots on the backs of those placed in the dry conditions.

  2. 'Bacteria. Friend or Foe?' Bacteria is something we are all reminded of ...

    By the 1980's this figure had fallen to 9 per cent and in 1993 it was less than 2 per cent (11). This bacterial toxin has the ability to paralyse and kill yet it is now used safely in a purified form marketed under the widely known name, 'Botox'.

  1. explain why Antarctica is so special and therefore why we need to protect it, ...

    Places that would benefit the most from the bergs are going to be places with the same extremes, but the opposites of them i.e. countries on the equator. The bergs also pose a scientific value: because some of them have been frozen for thousands and in some cases millions of

  2. The importance uses of micro organisms.

    Various bacteria are involved in a chemical process called fermentation used to make alcohol beverages. Sewage treatment plants use bacteria to purify the water. They can also be used to make certain drugs such as human insulin. Bacteria are of major importance in helping with research.

  1. Antibiotic Sensitivity Test

    The experimental dish showed varying degrees of inhibition of the bacterium by some of the antibiotics indicated by a clear ring. (See Diagram 3) The effect of the antibiotics was measured in mm as shown in the Table of Results below.

  2. The Effect Of Fertilisers On The Environment

    The use of fertilisers is sometimes referred to as 'The Green Revolution'. Amazingly, some scientists suggest fertiliser use may have prevented 'even worse' global-warming. Fertilisers allow farmers to increase their crops yield. Therefore, 'huge areas of rainforest' (New Scientist, 2004)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work