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- Posts: 2
- Joined: Thu Feb 05, 2015 12:50 pm
I've been working on an anion exchange method containing Alendronate, phosphate and phosphite.
Mobile phase is 0.5mM Nitric acid
Column is the same as that used in the EP - PSDVB packing
UV Detector
The problem is my peak shape is awful; particularly for Alendronate but phosphate and phosphite are poor too. All peaks start very gradual fronting to an apex where they then return to zero very quickly. This gives me a peak width (half height) of ~4.0mins but a height of ~0.06 AU. So components detected at 100% nominal but unusable - especially when going to those lower rel sub levels.
- Conditioned >24hrs
- Conditioned while injecting my components >50 injections
- I've tried reducing injection volume and sample concentration
- Different brand/type of anion exchange columns
- A wide range of pH (also different buffer salts to control said pH)
- Increased column temp
I cannot get the components off of the column quicker to form a "sharper" peak, coincidentally none of the peaks are made "much worse" by all of the above.
I'm completely stumped any help would be greatly appreciated.