Nitrite interference using Hanna High Range Nitrate checker HI-782

[KGV]

Does anyone know how nitrite levels affect this checker?

 

[Dan_P]

Does anyone know how nitrite levels affect this checker?

Nitrite will cause the nitrate Checker to read higher than the true value.

 

[KGV]

Nitrite will cause the nitrate Checker to read higher than the true value.

Thanks @Dan_P. I have about 0.1 ppm nitrite so I was hoping someone had correction curves.

 

[Dan_P]

Thanks @Dan_P. I have about 0.1 ppm nitrite so I was hoping someone had correction curves.

Correction curves are tricky. First, a correction only pertains to one particular kit because each kit contains a different amount of zinc.. Second, the amount of nitrite interference depends on the amount of nitrate present. The reason for this is that both nitrite and nitrate are reduced by zinc, nitrite to ammonia, nitrate to nitrate. Nitrate and nitrite compete for the zinc. More nitrate means less nitrite destroyed. The only straightforward way to measure nitrate in the presence of nitrite is to destroy the nitrite, e.g., with urea and concentrated HCl.