PDA Peak purity How to process data?

<p>I have aproblem about PDA peak purity.</p><p></p><p>We apply purity analyses for forced degredation studies. In a support document (which ? can scaned ) for waters millenium 32 which is written by Dr. Shulamit Levin in the year of 2001, the procedure for peak purity isclearly explained , and we use to apply this procedure.</p><p>According to this procedure we should inject 6 times standarts and process them by setting threshold determination as auto treshold.</p><p>after processing we determine the maximum value of purity angle and set it in the processing method under solvent and noise criteria for treshold determination. than we reprocess this 6 injections and verify that all standarts came out pure.</p><p>I guess this procedure is aplicable for standarts which are including only one component.</p><p>?n my case ? have to work with a standart which is including 6 components and ?'m really confused which purity angle should ? have select for solvent and noise criteria.</p><p>Do ? have to select for each component different processing methods ?n that case which method ? have to use by process?ng samples</p><p>or do ? have select the greatest purity angle of all components in all chromotograms. </p><p>?'m not sure that ? have explained my problem, because for me is the peak purity a hard stuff to understand </p><p>thank u for your help if u answer my question as soon as possible ? woul be very greatfull</p><p>Nilay</p>


  • bb


    This procedure was developed on M32. I suppose you have Empower (or higher versions of Milliennium). There Auto treshold is typically used. If Autotreshold returns standards (which should be pure) to be unpure (purity flag...) then I would go for alternative method, like the one described in the Dr. Levins paper. But you will have the problem that you can not set up more than one solvent angle. One possibility is to put in the highest purity angle you get from 6 peaks from 6 iniections and key it in as solvent angle. Another option is also to make six injections and make a library match: one peak is saved in library, the others are compared and the highest match angle can be to my opinion set as solvent angle. I would also like to say that I would increase solvent angle calculated from either methods to cover some of the uncertainty.

    Hope this helps.