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- Posts: 4
- Joined: Wed Jun 07, 2017 10:15 pm
Since then we obtained a new column but the peaks continued to elute with the gradient without making any injection even of a blank. We tried the washing of the system lines and the autosampler with solvents of diffferent polarity. Some peaks were removed but one still remains. We changed the cell, we excluded the autosampler, even the mixer after cleaning the solvent reservoirs, changing solvents and checking their UV-Vis spectra before their use but still this peak remains.
The mobile phase is a) water HPLC purity (0.2% phosphoric acid) additionally filtered through 0.45um membrane b) methanol HPLC gradient grade c) acetonitrile gradient grade. Through all the gradient the methanol and acetonitrile are always 1:1 v/v.
The interferences absorb only at 280 nm but are not fluorescent under the conditions of analysis (exc.280nm/em.320 nm).
Any idea that could help?