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- Posts: 20
- Joined: Thu Sep 17, 2009 9:55 pm
I am working on mannitol, lactulose analysis by LC/MS/MS. HPLC column is Prevail Carbohydrate column 150X2.0mm. flowrate is 0.3ml/min, 1uL injection.
I am using mannitol-13C6,sucrose-13C12 as internal standard, Initially I were using 73% acetonitril and 27% DIwater, It works fine for two weeks, then I lost sensitivity, I add 200ul NH4OH to the mobile phase, I get better sensitivity, it works for couple days, then lactulose peak shape degrade to tailing broaden big fat peak. However mannitol, mantol-13c6, sucrose-13c12 peaks shape remain perfect. Anybody knows how to solve this problem?
I am using mannitol-13C6,sucrose-13C12 as internal standard, Initially I were using 73% acetonitril and 27% DIwater, It works fine for two weeks, then I lost sensitivity, I add 200ul NH4OH to the mobile phase, I get better sensitivity, it works for couple days, then lactulose peak shape degrade to tailing broaden big fat peak. However mannitol, mantol-13c6, sucrose-13c12 peaks shape remain perfect. Anybody knows how to solve this problem?
