# Auto calculate calibration amount in Openlab CDS

Hi,

I am setting a method in OpenLab CDS where the ISTD (calbration) amount is different for each run. I am wondering if it is possible if we key in the ISTD weight in the sequence table, and the amount could be auto-calculated when I review the chromatogram?

C23:0 is the ISTD and would be spiked into each sample, hence the amount spiked in would be different for each run. The amount of C23:0 =  ISTD amount / 25

Thus my question is, is it possible to let the software auto calculate the amount of C23:0 (which will change the Level amount automatically for each run), by entering the ISTD amount and multiplier?  Parents
• Hi

What does your sequence look like?  How do you create the calibration?

What I see from your screenshots doesn't look like ISTD calibration, but a calibration using C23:0 as a reference.  I may be missing something Kindest regards

Andy

• Hi Andy, sorry, it should be more of a one point external calibration, and other curves are referencing to C23:0. Not sure if this is the correct way to create, but most of our methods are created in this way.

Technically there are four compounds to be measured, which are compound 2,3,5 and 6 in below table and the sum of these four compounds will give the result for Total PUFA. Compound 4 is the standard where we spike in for each sample. We would run the sample as calibration standard and clear all calibration every time. Before we run, the sample amount and ISTD amount is keyed in the table. Currently, all multipliers and dilution factors are set as 0. In this case, is there a way to auto-calculate the amount for Level 1 in the first picture by taking the ISTD amount we entered divided by 25.?

• Hi Andy, sorry, it should be more of a one point external calibration, and other curves are referencing to C23:0. Not sure if this is the correct way to create, but most of our methods are created in this way.

Technically there are four compounds to be measured, which are compound 2,3,5 and 6 in below table and the sum of these four compounds will give the result for Total PUFA. Compound 4 is the standard where we spike in for each sample. We would run the sample as calibration standard and clear all calibration every time. Before we run, the sample amount and ISTD amount is keyed in the table. Currently, all multipliers and dilution factors are set as 0. In this case, is there a way to auto-calculate the amount for Level 1 in the first picture by taking the ISTD amount we entered divided by 25.?

Children
• I can't think of a way to do exactly what you describe, but I'm sure that a custom calculation of some sort might achieve the same result.

Kind regards

Andy