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- Posts: 4
- Joined: Wed Oct 16, 2019 5:13 pm
I am from a pharma industry, and am developing methods for various products.
To give you a little brief, the methods are being developed in a R&D block and validated in a qc block. Both the blocks are in the same premises, but different buildings at a distance of about 100 meters from each other. R&D Block as Split AC installed, QC has AHUs installed with filtered air. (AHU of QC and microbiology lab is common)
We have developed methods for a product and all of the chromatographs (Raw material Assay & RS, Finished Product Assay and RS) were smooth and with the peaks at the right RTs. We transferred the method to the QC lab, but have been observing really peculiar behaviour in the BLANK runs in all HPLCs.
There are unknown peaks in blank runs in all HPLCs ( there are about 4 HPLC) at 5 and 26 minute and the peak area increases with every run. There are no peaks initially for 4-5 runs but start appearing from the 6th run and keep increasing. We tried changing the mobile phase A, B and even the diluent but the peak still remains. We changed the column to a one with higher pH spec, but the peak still remains though the RT shifts a little to 7 and 30 minutes. We changed the vial and mobile phase bottles. The peculiarity is that there is no peak in R&D, but two ghost peaks are always there in all runs, and they keep increasing.
Mobile phase is acetonitrile based. Diluent is ACN + Naoh.
As the peak increases over time, we thought it to be a leeching issue, so have tried changing everything but nothing seems to be working. Any support would be greatly appreciated