Peak ratio calculation

Hi,
we perform a limit test (CE analysis) with internal standard. The following detail s are given for evaluation:

-corrected areas: divide all the peak areas by the corresponding migration times;
-correction factors: for the calculation of content, multiply the ratio of time-corrected peak areas of impurity and the internal standard by the corresponding correction factor: impurity X = 3.0;
-impurity X: not more than 1.5 times the ratio of the area of the peak due to API to the area of the peak due to the internal standard in the electropherogram obtained with reference solution (b) (1.5 per cent);

Are there any peak fields which calculate the ratio of time-corrected peak areas of impurity and the internal standard? Or should we create new Custom fields?

Thanks in advance!!


Answers

  • Why can't you use the RRF field in the processing method to accomplish this?

    corrected area: seems like normalization by an ISTD. Set an internal standard for all components.
    correction factors: apply as RRF in processing method. 

    You would need a custom field to evaluate Impurity X

    Boolean Custom Field: GTE(Response, 1.5). 0 translation: pass; 1 translation: fail. 
  • Hi shaunwat,

    Thanks for your comment.

    For this CE analysis the calculation is not performed using the peak area, but with the peak field "Time Corr. Area". If I use the RRF field in the processing method, it has no influence on the Time Corr. Area. Furthermore I need the ratio of the time-corrected area of the API and the impurity.

    Since we use the CE-option, I thought that these fields might be present by default.


    Thanks a lot!
  • To be honest, I am not familiar with the CE option at all. In fact, I didn't even know a CE option exists for Empower. 

    You might want to wait and see if someone who is more familiar with the CE options replies...