Try this article http://www.sciencedirect.com/science/article/pii/S1658361215001389

You can use a photometric assay with Phenanthroline:

Prepare

-acetate buffer: dissolve 200 g ammonium acetate in 250 ml pure acetic acid and 50 ml purified water using a heater. After all is dissolved fill up to 500 ml with purified water

-phenanthroline solution: dissolve 0.5 g Phenanthrolinium-Chloride-monohydrate in 100 ml purified water

-acsorbic acid solution: dissolve 10 g ascorbic acid in 100 ml purified water (cannot be stored long, maybe 2-4 weeks in refrigerator and in the dark)

For measurement:

put 500 µL of acetate buffer in single use cuvette

add 2 ml of sample and mix

measuerment at wavelength of 512 nm on Photometer will give a reading for dissolved ferrous iron (Fe2+)

OR: add 200 µL of ascorbic acid solution, mix and wait for 20 min

measuerment at 512 nm will give reading for total iron concentration

If you do both, the difference between with and without ascorbic acid will give you Fe3+ concentrations

For calibration:

Use a FeCl2 salt to prepare a stock solution of dissolved Fe2+. Prepare standards using 1% HNO3 or 1 % HCl, NOT just water. If you dissolve FeCl2 in water at neutral pH, Fe will oxidize and precipitate.

Method will work from 0 - 500 µmol/L or 0-30 mg/L

If you look up in the Internet for Phenanthroline AND Iron, you will find some more protocols. They may use different buffers or another reagent for reduction of iron (e.g. hydroxylamine). It works well with different approaches.

in a nutshell what is the purpose and significance of research?