Elaborate sample set with bracketing

edited October 2018 in Informatics
Hi All,
I decided to sign up in this forum for a big problem. In our lab, we use sample set (SS) for assay and related substances with bracketing calculation on Empower 3. A typical SS is reported below.

5 Inj of STD first prep. (STD I)
2 inj of STD second prep. (Witness, STD II)
sample A
sample B
3 STD I 
sample C
sample D
3 STD I
...

Suitability is performed by RSD% of 5 inj. of STD I  and also a recovery on witness. 
First calibration: RF of 5 and recovery% on STDIs after samples A,B and then quantitate A,B.
Second calibration: RF calculation on STDIs after AB, check recovery on STDIs after CD and then quantitate CD...and more.

Sometimes only a single injection of STDI is used for bracketing calculation (ie only one inj of STDI before CD and only one inj of STDI after CD)

A single injection of STDI is used for checking recovery but also as a std for calibration.
Empower is able to do that? Is it possible to use only one SS?
I think using label and custom field I will solve the problem but I don't know in which way...

Thank you in advanced...

















Best Answer

  • edited October 2018 Accepted Answer
    Im not sure what you mean by "A single injection of STDI is used for checking recovery" I presume you also have a spec on the standards injected as calibration standards as in RSD of Area? 

    You can use labels and functions to help what you are looking for. Why not label the standard with 5 injections as A, then label the standard (or standards) after Samples A and B as B. Then insert the functions Clear calibration, calibrate (with A and B in the Label Reference against the Calibrate function) and quantitate using the labels set against Samples A and B, eg U0101 for Sample A and U0102 for Sample B. Then your Label Reference becomes U01*. 
    Repeat this set up with your next bracket, or if you are used to using S01 labels for Standards just Label the standard with5 injections as S0101 then the standard after samples A and B etc as S0201...and so on. 
    This would depend on your internal SOPs, does that specify how many standard injections are required after x number of samples? 

    If only single injections are used for calibration can you split the injections over different vials, eg Vial 1 Vial 2 and Vial 3 all contain Std1 but only Vial 1 is labelled as S010...etc then that can be referenced for the calibration. I don't know how else you could specify to only use the 1st injection. 

    If using all injections of standards to quantify samples, then choose Average by Amount in the component tab of your processing method.

Answers

  • Hi

     Very many Empower users use the ‘control’ functionality to evaluate check stds. You can enter the expected (known) value but process against earlier processed stds. 

    I’ve found that the eg 0.98 deviation results might need deviation x 100 or 1/(deviationx100) to match existing SOPs

  • 3 std 1
    1 std 1 calibrator (label S0101)
    1 std 2 calibrator (label S0201)
    1 solvent
    1 sample A (label U0101)
    1 sample B (label U0102)
    1 sample ... (label U010.)
    1 std 1 calibrator (label S0102)
    1 std 2 calibrator (label S0202)
    1 solvent
    1 sample ... (label U020.)
    1 std 1 calibrator (label S0301
    1 std 2 calibrator (label S0302)
    1 solvente

    check precisione with all std1
    first calibration with 4 std (S01* S02*) and quantitate U01*
    second calibrator with 4 std (S02* S03*) and quantitate U02*
    check calibration with 4RF for each bracketing
    check carry over


Sign In or Register to comment.