Automatic Signal/Noise calculation

Question

Hello, 
 I'm using Open Lab 2 to calculate the signal-to-noise ratio. When I choose the option "automatic (On blank recommended for EP", on which blank of the sequence is the signal to noise calculated? Over what time range is the calculation made? Does it take into account the injection peak? Thank you for your reply.

martin.adams · Answer

Hello, If you search the help, you can find more details on the SN calculations. For automatic calculations the last blank in the results set prior to the injection is used. So, if you run blanks throughout the sequence a blank is used for the injections after it until another blank is run. The auto time range calculation is shown below, it uses the RT of the peak in the calculation. Marty An automatically determined time region is calculated according to one of the following algorithms: If the reference signal is not long enough (EndTime - StartTime < 20*W 50 ) StartTime = starttime (of reference signal) , and EndTime = endtime (of the reference signal) If the reference signal is long enough, but the peak is situated too close to the starttime (t R -10*W 50 < starttime of the reference signal) StartTime = starttime (of reference signal) , and EndTime = StartTime + 20*W 50 If the reference signal is long enough, but the peak is situated too close to the endtime (t R +10*W 50 > endtime of the reference signal) EndTime = endtime (of the reference signal) , and StartTime = EndTime - 20*W 50 If the reference signal is long enough, and the peak is situated far enough away from starttime and endtime of the reference signal (t R -10*W 50 > starttime, t R +10*W 50 < endtime) StartTime = t R - 10*W 50 , and EndTime = t R + 10*W 50 where t R is the retention time, and W 50 is the peak width at half height.

Kris · Answer

Hi martin.adams , you are exactly right, the peak width is small, therefore it is not giving the final S/N value. When I manually integrated the peak by increasing the peak width, it gave the value. It seems i need to fix the time range for the baseline calculation. Thank you for your reply.

Automatic Signal/Noise calculation

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