[decon]

Hey. First time posting on these boards, I hope that you guys are able to help me with a rather tricky question (at least I find it tricky ). Anyways, we've been given the homework of reading about Ion selective electrodes (mostly SGE and SNE) and a few questions to go along with the text. I've answered all of them expect for one which is:

When you carry out measurements with a selective nitrate electrode, then the presence of Cl−, Br⁻, I⁻ and NO2⁻ will result in too high of nitrate concentrations values. Why does these exact ions interfere with the nitrate  concentration measured?

First of all tell me if you don't understand the question. It's originally written in Danish and I must confess that I don't have much experience in writing chemistry questions in English. Anyways, I just don't get why these ions would interfere with the concentration values. Any hints or help would be greatly appreciated, thanks 

[Borek]

Do you know how SNE is made?

[decon]

Do you know how SNE is made?

Well yeah, if I understand your question correctly. I'm lazy so I just took a picture of the book and translated the words:


Or do you mean like, how they actually make these things? If so then I have no idea