Hello, I am setting up a Nitrates testing methodology but need some help with appropriate sample prep.
I have a Nitrates Ion Selective Electrode probe and bench top meter (also displays sample's temperature and pH.)
We are testing feed samples (hay, silages, grains, total mixed rations, etc) for Nitrates (% Nitrates and ppm Nitrates-Nitrogen.)
We receive the feed samples fresh then we dry and grind them.
The probe came with ISA packets (Nitrate Ionic Strength Adjustor powder) where you will add one packet of ISA to 25mL of sample or standard.
We have a mechanical shaker
We have filter paper, lab glassware
What should the sample prep be?
How much dry, ground sample diluted in how much water?
I hope no digestion / extraction is necessary?
Should we shake the samples? for about 20 to 30 min?
Add ISA before or after filtration?
Thank-you very much!