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- Posts: 4
- Joined: Tue Sep 09, 2025 10:40 am
Hello everyone,
I’m seeking advice on a persistent UPLC issue in an established amino acid method.
Until mid-November the system was performing normally, but we suddenly began observing partial or complete co-elution and pronounced tailing in several amino acids within a 17-amino-acid standard. The problems consistently involve only serine, arginine, cystine and lysine. Overall resolution has decreased to the point where quantification is unreliable.
We are using a UPLC amino acid analyser with gradient elution on a reversed-phase system. I have already replaced the stationary phase with a brand-new column, but the issue remains unchanged. Fresh standards are prepared daily and the mobile phase is freshly prepared each time, yet the chromatograms show exactly the same behavior.
If anyone has encountered similar co-elution and tailing issues under these conditions, I would greatly appreciate any troubleshooting recommendations.
I’m seeking advice on a persistent UPLC issue in an established amino acid method.
Until mid-November the system was performing normally, but we suddenly began observing partial or complete co-elution and pronounced tailing in several amino acids within a 17-amino-acid standard. The problems consistently involve only serine, arginine, cystine and lysine. Overall resolution has decreased to the point where quantification is unreliable.
We are using a UPLC amino acid analyser with gradient elution on a reversed-phase system. I have already replaced the stationary phase with a brand-new column, but the issue remains unchanged. Fresh standards are prepared daily and the mobile phase is freshly prepared each time, yet the chromatograms show exactly the same behavior.
If anyone has encountered similar co-elution and tailing issues under these conditions, I would greatly appreciate any troubleshooting recommendations.
