Notes on chlorophyll extraction and nitrite testing
We didn't have a test for nitrates, but we did have sulfanilic acid to test for nitrites so we tried reducing the nitrates to nitrites with Zn powder. We calculated that the sensitivity was one small spoonful from the jar could measure 1-100mg/L nitrite
Method: Nettles 10g nettles in boiling water 20 mins nitrates Split 3x 10ml in test tubes (one is a control) Add some powdered zinc to one tube to reduce the nitrate to nitrite
4th control to show test is working by adding one spoonful and the colour goes lighter (pH will be decreasing maybe that's why)
Observations No change - half the samples and add another 2 spoonfuls of testing powder to each of the testing test tubes - shake - with zinc turns slightly pink
Method: Lettuce Repeat. After first addition of zinc and powder the +Zn goes very grey and the other goes slightly paler than control. Halving an adding an extra spoonful on the one with zinc. Observations not much change
10g nettles / lettuce pounded with 50ml water / acetone mix in a cold pestle and mortar to a paste - 2 hours the sediment should be not green at the end
After 2 hours we get the chlorophyll out in the acetone mix. Washed it and diluted. Burned off the acetone to make it more concentrated. Could try turning into paint?
Wash off acetone with isopropanol and then water then add 20ml of the goop to a test tube, warm and add the oxidising persulfate. Warm 2 mins then cool down.
Adding zinc to one goes grey then the liquid goes clear. Add powder nitrite test both tubes go brown. Eventually tube with zinc (thus with nitrites) goes a little bit pink (well pinky brown). Some success..!