Bracket Standard Recovery Custom Field

gdun

hello,

 I'm trying to figure out a way to calculate the bracket standard recovery using a custom field? i.e, the % difference of the bracket standard injections compared to the previous standard (bracket) injections. 

Empower2019

My username seems to have been wiped for some reason..

Cant you use a report for this? Label your standards as sequential eg S1 S2 S3...Sn etc, Then create peak tables which calculate the %RSD between labels S1 and S2 then S3 and S4 etc? You can use Data Filtering Conditions in the peak table of the report method to do this. 

gdun

our sop outlines the following equation to calculate percent bracket recovery: 

% bracket recovery =[|A-B| x 2/ (A+B)] x 100

Where              A:        Mean area response of standard prior to the sample loop

                        B:         Mean area response of standard after the sample loop

Currently we use excel to calculate this , but  we are trying to get  away from the use of excel sheets (for data integrity purposes). I don't believe the report can do this , it would need to be a custom field from what I see

Empower2019

Ok I see. How many injections of standard do you do? Ill presume 2. Label your standards as A and B. Make 2 peak, real calculated custom fields called A_Std_Subtraction and B_Std_Subtraction and code it as (A.1.(Area)+A.2.(Area))/2 and (B.1.(Area)+B.2.(Area))/2 and make sure to tick All or Nothing in custom field editor for both CFs. Then make a third peak, real cf called Recovery_Brkt_Stds and code it as ABS((((A_Std_Subtraction-B_StdSubtraction))*((2*(A_Std_Subtraction+B_Std_Subtraction))))*100)


Adding an ABS will allow for any negative values. This should work if you label all your standards as A and B so A----samples----B then another set of A......samples....B etc. Because of all or nothing, your % bracket std recovery should only generate a result for all the B standards, where all arguments are present. So at each B injection, your value for Recovery_Brkt_Stds will calculate using the current B and the previous A injections, then this repeats again for the next set. But this assumes you are using a Sliding No Overlap method of standards injections where you quantitate your samples off A and B, clear calibration then start again with a new A and B. If not this wont work. Also, there is every chance there is an easier way to do this, im just going by what I see and I haven't access to a test project, so good luck.