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Extracting algal pigments
How do I extract and separate algal pigments? I have tried the plant pigment experiment in Osmosis and it works with TLC (silica gel). However, for algae, some references suggest using cellulose TLC instead of Silica Gel.
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Measuring vitamin C - some unusual results
Our class did an experiment to measure vitamin C in different fruits and vegetables. We used two different methods, DCPIP and Starch-Iodide. Both gave similar results with most things we tested but when we tested brocolli we got very strange results. When we tested brocolli with Starch-Iodide we found it had about twice as much vitamin C as orange juice. this is about what the published results on the Internet led us to expect. When we tested with DCPIP we found that the brocolli stalks gave the same result as with Starch-Iodide, but the brocolli flowers did not decolourise DCPIP at all, though they did decolourise Starch-Iodide.
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Ethene bioassay - further questions
For the ethene bioassay why do the seedlings have to be kept in darkness? Is it possible to have them in sealed boxes that can be exposed to (constant) light at a fixed time every 24 hours?
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Measuring leaf surface area
I am looking at rates of photosynthesis and need an accurate way of recording leaf area. I have tried drawing round the leaves but they often slip and wilt.
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How does chromatography work?
We extracted pigments from spinach leaves. The leaves were boiled in ethyl alcohol (95%) then the extract was put on a strip of chromatography paper and suspended in petroleum ether containing 1.5% propyl alchohol. Different pigments moved up the paper. What are these substances and how does chromatography work?
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