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Vitamin C. Core Practical. Throughout this investigation we will aim to find whether the amount of Vitamin C in various fruit juices sold at supermarkets are as high as they claim to be on the packaging.

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Introduction

Vitamin C. Core Practical Introduction: Throughout this investigation we will aim to find whether the amount of Vitamin C in various fruit juices sold at supermarkets are as high as they claim to be on the packaging. To test this we will add these various juices into a beaker or test tube contain DCPIP (dichlorophenolindophenol) one drop at a time, one the solution has turned clear we discontinue testing and record the results. We then calculate the volume of each drop and compare the results against the control of 1% vitamin C solution, which we know to contain 10mg of vitamin C. When vitamin C comes into contact with DCPIP, a series of chemical changes occur that change the color of the solution. Vitamin C is an essential nutrient of all living beings, and can be made internally, however also needs to be in our diets to maintain a healthy level, without it the disease scurvy can surface which leads to bleeding from the mucous membranes. Vitamin C is also required for a number of metabolic reactions that without we cannot survive. ...read more.

Middle

We then filled a syringe with the liquid and began allowing one drop at a time to fall into the test tube. 3. After each drop we would lightly shake the test tube to ensure the solution was fully mixed, and continued this until the solution was satisfactorily clear at which point we wrote down the number of drops that had been administered into the solution and proceeded to redo the test with another juice. 4. We began the investigation by testing a control of 1% vitamin C solution that we knew had 10mg of vitamin C in 1cm3. 5. Once we had tested this we continued to test the fruit juices and compared the results against the control and attempted to estimate the amount of vitamin C actually in the juices. 6. The independent variable would be the fruit juices and their different vitamin C levels, and the dependant variable would be the amount of DCPIP. Risk Assessment: There is not a lot of risk involved in this investigation, it is vital to follow the standard lab procedures. ...read more.

Conclusion

To make my results both more comparable and reliable, I should investigate further into categories i.e. freshly squeezed, diluted and different concentrations for all the juices and see whether this makes any difference. In a real life case this would mean, people with scurvy would gain more benefit in terms of vitamin c level, if they drunk orange juice compared to apple juice. Evaluation: I think this investigation, from my results showed that the most vitamin C in fruit juices in contained in orange juice. The only problem with my results was, I had to re start the investigation half way through, due to a contamination in the DCPIP, and this meant all my results where no longer accurate, this then took a long time to re clean my pipettes, and start again with a new mixture if DCPIP, as the other one was contaminated and was partially oxidized already. This pro longed the process as a whole, but in the end meant the results were more reliable. However, I do feel more background research should have been received on the juices for example if they were pre packed or diluted etc. ?? ?? ?? ?? ...read more.

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3 star(s)

***
This account of the investigation lacks the attention to detail needed to gain high marks. There are a number of omissions and errors. Checking finished work carefully is often helpful in reducing these.

Marked by teacher Adam Roberts 05/09/2013

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