Sensibility

Hi julia.jsd thank you for participating in the Agilent Community!  I moved your question to the Chromatography Software forum for better visibility.

Would you please let us know what version of OpenLab CDS Software you have?

Thanks,

Kristen

Hello Kristen,

Many thanks to move it, I use 2.5 version of Openlab CDS!

if you need to calculate you S/N ratio follow these steps:

from processing method , select system suitability ==> properties

at bellow you see peak detection performance .

select all peak , and your noise calculations method ( ASTM or P2P)

then go to noise region , if you select automatic he will compare your peaks with your blank injection and you need to identify the blank in sample list .

.. 

or you can select Fixed range  from (current) not (blank) if you don't have a blank injection

Hello Mohammad ,

Thanks for your reply, what is the time that I need to include? What is the difference between fixed and relative?

If I choose the blank in the injection list?

Hello,

My first suggestion would be to do a search in the help for System Suitability as the help gives all the details. If you have a blank injection, you can setup the noise as automatic and that will work for most applications. I copied the main SS method noise setup help below. 

Marty Adams

1. In the Processing Method window, select the SystemSuitability > Properties node.

2. Under Peak detection performance, set Signal to noise to All Peaks.

3. Select the required Noise calculation and Noise range settings. Choose the settings according to the current pharmacopeia guidance and according to the Standard Operating Procedures in your laboratory.

   The EP, USP, and JP check boxes are only relevant for the column performance calculation.

   • Noise calculation - see Signal-to-noise calculation

     ASTM - see Noise Calculation by the ASTM Method

     6SD - see Noise Calculation Using Six Times the Standard Deviation

     P2P - see Noise Calculation Using the Peak-to-Peak Formula

     RMS - see Noise calculation using the Root Mean Square (RMS)

   • Noise range - see Signal-to-noise calculation

     Noise range Automatic: the noise is calculated in the last blank run (sample type = Blank) which was acquired before the injection. The range is calculated at the retention time of the peak -10 and +10 times the half peak width on the corresponding signal.

     Noise range Fixed: the noise is calculated in a fixed range of the current signal or the last blank signal.

4. Reprocess the injection.

5. In the Injection Results window, display the S/N and Noise columns.

   The S/N column contains the signal-to-noise ratio as calculated with the chosen algorithm. The S/N EP and S/N USP columns will be empty after reprocessing.