Chromatography Forum

Hi all
I'm working in Custom fields intersample in empower, and I need to create a formula for %RSD(area) of Std bracketing. The sample set is as follows:
Std1
Std1
Std1
Std1
Std1
Smp1
.
.
.
Smp7
Std2
Smp1
.
.
Smp7
Std3
.
.
.
and so on.
(STD1 = STD2 = STD3 = ... = STDn),
The problem is that I need to %RSD be punctual, ie the calculated RSD of Std2 is with the area data of STD1 (all injections) and STD2, the STD3 is with STD1, STD2 and STD3 and so on.
Any idea how to create this custom fields?
Please help.
Many Thanks

Hi

Maybe try something like :
B.%..%RSD(Area)/C.%..Area

Where B = label for std 1
C = label for std 2
D would be std 3 etc

or incorporate default :

SAME.%.%.%RSD(Response)

Sorry , I havnt got empower in front of me so I maybe wrong

SAME will not work, since the empower will return the equal value for all STDs and will not perform the calculation of %RSD differently for each STD.
Using different labels implies having several custom fields which is something I am trying to avoid,
Thanks for the reply

yeah ofcourse you are right

Maybe try custom field with report restrictions by name to minimise custom fields

Can you be more clear about the custom field with report restrictions?

Plz someone help, any idea helps

Do you perform "Clear Calibration, Calibrate, Quantitate" after each set of samples (bracketed by 2 standards)? If so:

1. Give each of your standards a unique label eg Std 1 = S01 Std 2 = S02 etc.

2. Create a calculated custom field (Result, Real, Calculated) called "Incremental_Std" as follows "S%.%.RSD(Area). This formula excludes channel but will pick every injection.

3. Ensure you have the "All or nothing" box ticked and The Search order set to "Result Set Only" when creating the Custom Field.

4. After the Quantitate line, select "Summarize Custom Fields Incrementally" and repeat this with your next block of standards and samples. This way, the RSD of Std 1 and 2 will be calculated, followed by the RSD of Std 1,2 and 3 etc.

Hope this helps.

Hi

Another way of doing it by Empowerbanes

I was thinking have a generic custom field set up then restrict std summary by name in the report

I would go with points made above though

I will try this option, and then i will tell the results. Thanks btw i process the results by using the option "Process" in the sample set, and dont use the lines Clear calibrate, calibrate and quantitate in the sample set, only the Summarize custom fields, because when i use the option Process there is a mark to do that. Can you explain me what is the difrence? Because i see most people in foruns using that lines but i can't understand the difrence.

hi

You may want to consider using these for the std acceptance criteria you require

Clear calibration - Deletes calibration curve with the processing method
Quantitate - for samples without stating the label ref
Calibrate - all stds above this in the sample set will be calibrated

so maybe sequence
S1 X5
smp1
.
.
.smpl7
Std2
then add Functions :
Calibrate
Quantitate
Summarise custom fields
Std3
smpl1
.
.
.
smpl7
Std4
Calibrate
Quantitate
Summarise custom fields

I tested the fuction summarize custom fields incrementally and it worked:)) thanks very much.

Going through the SSM wizard will get you close to this sort of solution if you try the different standard treatments and study the resulting table's processing column.

Hi,

I would like to create a formula for %RSD(area) of standards and I don't know how to use the functions: Clear Calibration, Calibrate, Quantitate and Summarize Custom Fields.
Many thanks.

Hi,

I would like to create a formula for %RSD(area) of standards and I don't know how to use the functions: Clear Calibration, Calibrate, Quantitate and Summarize Custom Fields.
Many thanks.

You can find them in the "Function" field of your sample set.
I wouldn't create a custom field for RSD unless 100% required- just use the summary function RSD in your report method on groups of Areas, Amount, Tailing etc.