Peak Purity in Openlab CDS 2.3version

Question

Dear All,

we are using openlab CDS2.3 Version and i have done some trial with force degradation of API and using the openlab CDS 2.3 version gave some weird result of peak purity and spectra with standard and degraded sample. Using 50% threshold value in the standard sample solution i am still getting peak purity failing and while in the degraded sample shows more pure then in standard which is not making any sense. I have attached the screen short to see if any one can help with the following point. There are 2 pic attached in the first pic sample (API) with 0.5M HCl and in the second pic it pure standard SST solution. further in the 2nd pic i overlaid the SST and sample solution if you see the spectrum is not matching at all.

what is the purity in term of regulations
how we can set up the threshold value in Oenlab CDS.
will the sample concertation will have an impact on peak purity. Regard

ryoboyle · Accepted Answer

Hello,

I have added tags to this post to increase visibility.

1) I don't know what regulations you are referring to, so the best way I can think to address this questions is to just provide information on how OpenLab CDS calculates the impurity evaluation. See below:

Where Threshold and Match Factor are calculated as below:

2) The only real way for a user to impact the threshold calculation is by manipulating the Impurity sensitivity set for the compounds in the Processing Method:

3) Sample concentration should not have any impact on impurity as long as concentration does not impact a compound's spectra.