I’ve just been reading about the analysis of nitrite levels in water samples and low spiked recovery in some samples.
This was attributed to oxidation of the nitrite ion by components unknown within the water samples.
The solution that was proposed was to add low levels of thiourea to the spiked samples, which dramatically improved the recovery of the spiked samples, without interfering with any of the rest of the analysis.
Has anyone else had issues with oxidation (or just low recovery of spiked samples) during nitrite analysis and tried this approach?
Hello:
I am not using IC, I remember that in my past experiences we did not do IC for nitrite because it did not work very well and UV was better for us. In my lab (we do API) we are doing UV with the spectrophotometer. As far as I know, what thiourea does is derivatize nitrite and it could be seen by UV…
I’ll give you the Thermo application, where they talk a little about the problem of seeing it through iC and combine it with UV detection.
I also tell you something: We have seen that the material as a filter can provide you with nitrites. So validate your filter provider because you may have problems in sample preparation.
Cheer up!
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@IreneNS Interesting enough you mentioned about the filter. At the FDA/CRCG workshop yesterday couple speakers brought attention to filters used that could contribute to false positives; so they switch to using centrifugation. Another one that was new to me was the formation of Nitrites in the excipients when exposed to air under certain conditions, crazy!
Stay in the look out when we shared the presentations and recordings of the meeting. Thanks for your contributions!
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