waters PDA help

[shadow]

I am working on an impurity method by HPLC.separation is great, peaks are sharp, there are more peaks than expected but now that I analyze in a PDA angle is 0.5 and threshold is 0.3. According to waters software peak is not pure, has anyone had this happen? and where to go next? more MD? Any help with handling the software would be appreciated.

[prepcolumn]

I am working on an impurity method by HPLC.separation is great, peaks are sharp, there are more peaks than expected but now that I analyze in a PDA angle is 0.5 and threshold is 0.3. According to waters software peak is not pure, has anyone had this happen? and where to go next? more MD? Any help with handling the software would be appreciated.

Do you mean the impurity peak or the main peak? If you mean the main peak and if it is overloaded or giving very high absorbance you may face with such kind of problems.

[aceto_81]

[quote="prepcolumnDo you mean the impurity peak or the main peak? If you mean the main peak and if it is overloaded or giving very high absorbance you may face with such kind of problems.[/quote]


If this is caused by overloading, I would expect much higher numbers (angle 5.0 and threshold 3.0 or so).

You can take a look at the purity plot to see where the problem lies, or take a look at the maximum impurity spectrum.

Ace