Practical investigations
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What are the advantages and disadvantages of using the different techniques (NBS, DCPIP and colorimetry) to detect vitamin C content? Thanks.
Igloo writes
You need to carry out an error analysis using the titration methods and compare your results with those obtained from carrying out the same analysis with the colorimetry. I cannot do this for you, because I have no information about the accuracy or otherwise of the colorimeter you have used, nor about the specific reaction whose colour you are measuring.
Another point worth making is that DCPIP titrations can give rather unreliable end-points owing to the lack of a really sharp colour change. Furthermore, the concentration of DCPIP solution itself tends to “wander”, which is why it should always be freshly prepared and standardised before use.
Always carry out a risk assessment and check with your teacher before starting any practical work.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
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updated: 13 December 2006
