How to fix linearity of signal issue with HILIC column?

05 August 2023 1 9K Report

Hello everyone,

I recently had my MS machine cleaned since then i am facing an issue regarding implementation of my method for ascorbic acid using Sequant ZIC HILIC-MS/MS.

I see a break in my linear curve which was not the case before. The Ms had undergone rail cleaning and detector voltage was changed. However, I believe this is not the issue. I use 5 mM NH4actate and ACN as eluents. The AA eluted in the isocratic step with 90 % ACN.

I encountered the same problem when I was developing the method and I managed to adjust it (i.e. pH change and injection volume). However after months since the rail cleaning of MS was done the problem is back.

Kindly suggest how to troubleshoot it?

Hassan Zia

Just to add, if you look closely the calibration curve looks like an upwards quadratic curve. As I mentioned. it was linear before. kindly suggest how to troubleshoot and see what went wrong ?

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