Empower 3 sample set creation and custom fields

[dedeepya]

Hi,

I am currently trying to calculate SST (Reproducibility and Repeatability- using two different preparations of standards of same concentration) and Assay content of samples using Empower 3. I could reach to a point where I can create a sample set with the amounts of standards entered and was partly successful in getting the results by creating custom fields like Avg Area of first std preparation, Average area of second std, weights of stds. But the issue is no value was shown in that custom fields when I tried to integrate the peak manually.
Could you please also explain how to create sample set and the label/ label reference sections in that sample set for calculating the assay content using bracketing standards (I believe label reference plays a key role in calculation but not sure how to create one!)
Any help would be much appreciated.

Thanks,
DS

[ydna6969]

Hi ,

I think I understand you problem
If I am not mistaken your SST in your sequence will be (sorry I tried to add Empower sequence as image but would not work):

DIL
S1
S1
S1
S1
S1
S1
S2
S2
Sample 1
Sample 2
Etc

Label S1= B, Label S2 = C and label First bracket samples D, 2nd E etc

create custom field say : av_area_S1 =B.%..AVE(Area)
av_area_S2 =C.%..AVE(Area)
Function at end of sample set should include quantitate for D, E etc as normal

For manual integration do not calibrate or change processing method
Select use existing integration when you reprocess your results and calibrating and quantitating will make sure last results will be printed /signed

Hope this helps

[artsjeroen]

For bracketing standards it is very useful to use the method set wizard. The manner of how the sample set is set up depends on what kind of bracketing you want (average all, before each sample group, etc.)

Set the processing of all sample injections to "Don't process or report" and the standard injections to "normal" put two lines at the bottom of the sample set:
1) Calibrate: S* (labels of the standards to be used in calculations)
2) Quantitate: U* (labels of the samples to be used in calculations)

For the calculation of custom fields you should try to add "Summarize Custom Fields" at the very bottom of the sample set since you are using a summarizing custom field.

[alba88]

Hi, i have a problem with custom field calculation. This is my tipically sample set: S1
S1
S1
S1
S1
S1
S2
S2
Sample 1
Sample 2
S1 (bracketing standard)
Sample 3
Sample 4
S1 (bracketing standard)
I have calculate the average of the first six S1, the average of two S2, the RSD of first six standard S1. But I can't create a custom fields for RSD of each single bracketing standard with the first six S1. Can someone help me?

[DR]

As mentioned above, use the wizard to create the SSM, specifying 2 injections for everything. The rest can be done by making a few different versions of a peak table in your report method.
Initial standard should be changed to 5 injections and bracketing standards changed to single injections.

Then make a peak table that filters output to results from label S0101 - that's your first 5 std injections, include average, %RSD. Copy & paste table below original, change filtering to S0102 (or whatever label is assigned to S2).

Then make a third version, use filtering to exclude standards and group by label. This will cover all of your samples.

I don't think there's an easy way to get average for S2 and RSD for initial injections of S1 into one table, but you should be able to get what you need w/o using any custom fields - this is pretty routine stuff.

If you need to generate a curve for each addition of nested standards, you can also accomplish this by using tables w/ careful filtering, or study up on the summary custom fields as I think it is possible to get sort of a running total going - but I don't remember the specifics.

If you want to go down the CF rabbit hole, this may be a good slide deck to start with:
http://www.waters.com/webassets/cms/lib ... Fields.pdf

[lczenith]

Hi all, regarding the topic of "Intersample summary calculation," I am trying to process a large sequence.

ST S0101
ST S0102
ST S0103
C C0101
U U0101
U U0102
U U0103
ETC
C C0102
Clear calibration
CAL: S01*
QUANTITATE: C01* U01*
Clear calibration
SD S0201
SD S0202
SD S0203
C C0201
U U0201
U U0202
U U0203
ETC
C C0202
CAL: S02*
QUANTITATE: C02* U02*

CF order:
A - to get the ave area: S?...AVE(Area)
B - to get the concentration
C - to get the mean ave area: S?...AVE(B_STD_Conc)

Problem: When the second group of standards (STDs) is processed, the mean area is different. Any ideas?

Thanks.

[EmpowersBane]

You need to insert a % in the formulas for the averages, otherwise Empower will just take the value before the current injection and exclude the current value and therefore the final values will be different.

S?...AVE(Area) change this to S?.%..AVE(Area)

S?...AVE(B_STD_Conc) change this to S?.%..AVE(B_STD_Conc)

and make sure the function Summarize Custom Fields is inserted as the last line of the sample set. Check your search order for the custom fields. For Intersample summary fields, its best to pick Result Set Only for 99% of cases and then when you process a sample set the results will all populate in the result set.

[lczenith]

Hi, thanks for the reply. I didn't explain my problem very well. When I use the CF 'S?...AVE(AREA)', the correct mean area is calculated for the first group, but for the other groups, I get a different mean area. For Group 2, the corresponding mean area is not real. I want to calibrate and quantify each group with its own corresponding calibration. So this CF that you suggest gives me the mean total area from all the STD injections.

ST S0101 - Group 1 start
ST S0102
ST S0103
C C0101
U U0101
U U0102
U U0103
ETC
C C0102 - Group 1 and
Clear calibration
CAL: S01*
QUANTITATE: C01* U01*
Clear calibration
SD S0201 - Group 2 start
SD S0202
SD S0203
C C0201
U U0201
U U0202
U U0203
ETC
C C0202 - Group 2 and
CAL: S02*
QUANTITATE: C02* U02*
etc
Summarize custom fields

[georgelin]

Your question is common in industries. Especially for pharmaceuticals.

In your case, there are two options you can do.

1. separate the one sample set into two. And process with one processing method. and SST can be get from first one with RSD and average value can also be get relatively easy. as below

Sample set #1:

S1
S1
S1
S1
S1
S1
S2
S2
Clear Calibrate
Calibrate with S1*
Quantitate S2

Sample Set 2
Bracket (S1)
your samples
Bracket (S1)
Clear Calibration
Calibrate Bracket
Quantitate Samples
Summarize Custom Field

2nd option
Put the sequence in one as above. but put the sample set process as do not process and for rest row put Normal.

Hi,

I am currently trying to calculate SST (Reproducibility and Repeatability- using two different preparations of standards of same concentration) and Assay content of samples using Empower 3. I could reach to a point where I can create a sample set with the amounts of standards entered and was partly successful in getting the results by creating custom fields like Avg Area of first std preparation, Average area of second std, weights of stds. But the issue is no value was shown in that custom fields when I tried to integrate the peak manually.
Could you please also explain how to create sample set and the label/ label reference sections in that sample set for calculating the assay content using bracketing standards (I believe label reference plays a key role in calculation but not sure how to create one!)
Any help would be much appreciated.

Thanks,
DS

[lczenith]

Hi @georgelin, thanks for the reply.

I am avoiding the first option and I always use "Don't process or report" and "Normal" for Clear calibration, calibrate, quantitate and summarize custom fields.

I'm still looking for another way to do that.

Thanks.