Sciencemadness Discussion Board

Test for nitrite

MeshPL - 23-2-2016 at 11:57

Hello everybody!

I was wondering if any of you know a good test to detect small amount of nitrites in presence of:
-some alcohol (traces)
-a lot of nitrates
-little fluoride
-some metal ions (Pb, Cu, Ni, little Na)
-highly acidic pH (around 1)

Thre were some nice tests, like thiourea + iron (III), sulphamic acid + barium, azo coupling, indole nitrosylation but I'm not sure if they will be good for those conditions. Also indole or reagents for azo coupling are hard to get.

[Edited on 23-2-2016 by MeshPL]

UC235 - 23-2-2016 at 12:15

Nitrous acid has a pKa of 3.4 so anything more acidic than that is going to get you HONO from nitrites and it decomposes quite readily.

MeshPL - 23-2-2016 at 12:20

Yea, but I'm pretty sure traces will remain I think, and I want to detect those traces.

Unless, you say, that there will be no detectable traces, than I may give that up.

nezza - 24-2-2016 at 07:51

Azo coupling should work and is likely to be quick, easy and sensitive.

woelen - 24-2-2016 at 09:37

Add some thiocyanate salt. You obtain some nitrosyl thiocyanate, which is very dark brown in aqueous solution and slowly decomposes. This reaction is quite sensitive.