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- Posts: 108
- Joined: Fri Sep 03, 2004 3:42 pm
- Location: South Africa
Has anyone experienced any problems with the method for Monodechlorovancomycin in Vancomycin HCl. When we start the analysis we have a symmetrical peak with a tailing factor of 1.0. After about 50 injections the peaks start to front and the tailing factor is about 0.8. We have tried a Waters Xterra RP 18 (one recommended by the USP), as well as a BDS Hypersil. Both columns showed the same phenomenon with the peak starting to front after about 50 injections.
USP conditions:
Mobile phase: Dissolve 2.2 g of 1-heptanesulfonic acid in about 500 mL of water, add 125 mL of acetonitrile and 10 mL of acetic acid, and dilute with water to 1 L.
Mode: LC
Detector: UV 280 nm
Column: 4.6 mm × 25 cm; packing L1
Column temperature: 60
Autosampler temperature: 5
Flow rate: 1.5 mL/min
Injection volume: 50 µL
Any advice or recommendation would be greatly appreciated.
Mike