Chromatography Forum

Can anybody suggest me how the S/N ratio Calculated in Empower,i need an example, this is for determination of Limit of Quantification by S/N ratio aprroach,
at presnt we are injecting six blank injections and determining average "Baseline Noise ". Now injecting solution having lowest concentration of analyte, dividing this height with average Baseline Noise, but as per USP it should be 2h/N, told by somebody recently, please explain

Hi

Indeed, USP has harmonized with Ph Eur and ICH Q2(R1) guideline. See ICH guideline at www.ICH.org for details.

Text from current USP:

The signal-to-noise ratio (S/N) is a useful system suitability parameter. The S/N is calculated as follows:
S/N = 2h/hn
in which h is the height of the peak corresponding to the component concerned; and hn is the difference between the largest and smallest noise values observed over a distance equal to at least five times the width at the half-height of the peak and, if possible, situated equally around the peak of interest.2S (USP32)

This has been discussed at length, check the archives. Most of us thought the factor 2 being ridiculous as it is immaterial to the accuracy etc., whether you multiply by 2 or not.

can you help me how can i get this info from archive

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