calculate with latest retention times in Custom Calculator

Hello,

I am not sure what you are trying to do in the post request. The peak RT is the found time for each peak and would always be current. Are you asking about the expected peak retention time? You may need to provide more details on the calculation you are trying to accomplish. The common calculation I see are for RT is a request to compare the average peak RT in the standards with the peak RT in the samples.  

Marty Adams

Hi Martin,

I want to put the Retenion Index into a System suitability report. Its calculated ao with the use of retention time of several peaks. Thats why I would like to know how to get the retentiontimes from the latest datafiles from the different compounds into the custom calculation.

Hello,

I am still unclear what you are requesting. You will always be working with the current results when using custom calculations. You cannot store anything in CC it is only used against the active results. 

Marty

Hi Martin,

As I tried to explain I would like to put the Retention index (RI) into a System suitability report.

Calculating the RI is done by this calculation:

I figured if I know how to get the retention time of a certain compound (x,y or z) from you I'll figure out the rest of the calculation of how to put it in CC myself.

Hello,

I have done this before by using a custom dll and report template to calculate the RI index from a calibration file, written by the same report when running standards. This is complicated solution and requires VB.net or C# programming knowledge to read and write the calibration file and do the calculations. The benefit of this method is you can store the RI calibration without a new copy of the method each time.  Another solution done in CC is part of our match compare software so I cannot give it out fully, but I can give you an idea how it works. It uses the expected RT in the method to store the RT of the index peaks. You would run your index calibration run as a cal standard and setup in the method to update the RT of the peaks at 100 percent for calibration runs, so the expected RT would be set as the found RT of the index peaks. We also use the peak name to assign the carbon number. Below are examples of how we use the expected RT to get the RT and carbon number of the peak before any given peak. With these values and the upper values you can do the RI calculation.

Marty

LowerRT

if (Compound_Name.StartsWith("C") and IsNumeric(Mid(Compound_Name,2)),double.NaN,CurrentSignal.AllIdentifiedPeaks.union(CurrentSignal.AllMissingCompounds).where(function(x) x.Compound_Name.StartsWith("C") and IsNumeric(Mid(x.Compound_Name,2))).orderby(function(x) x.Compound_ExpectedRetentionTime).where(function(x) x.Compound_ExpectedRetentionTime<CurrentPeakOrGroup.Peak_RetentionTime).last().Compound_ExpectedRetentionTime)

Lower CN

CInt(Mid(CurrentSignal.AllIdentifiedPeaks.union(CurrentSignal.AllMissingCompounds).where(function(x) x.Compound_Name.StartsWith("C") and IsNumeric(Mid(x.Compound_Name,2))).orderby(function(x) x.Compound_ExpectedRetentionTime).where(function(x) x.Compound_ExpectedRetentionTime<CurrentPeakOrGroup.Peak_RetentionTime).last().Compound_Name,2))