During analysis NDELA Area observed dropped in standard solution after running sample what could be the reason
We have observed similar issues with other nitrosamines. In most cases, a simple wash gradient between the sample and the reference run resolves the problem. If your method starts with a relatively low water content (e.g., 40%), it can be helpful to introduce a high aqueous phase during this wash step.
Did you perform the method validation yourself? How was the initial accuracy?
In our case the validation itself worked flawlessly. However, after some time in routine analysis, the same issue appeared. Once we implemented a flushing gradient, the system performance returned to normal.
It is very likely that components from your matrix are sticking to the system and then eluting during the reference run, causing signal suppression. Sometimes chaning the syringe cleaning procedure and solvents can also help.
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