Chromatography Forum

Hi to all i have doubt about the relation between Resolution and separation, Minimum resolution we are following between any two peaks is 1.5, Is there any percentage relation is there to express the separation based on the resolution? Like some XX Resolution is equal to some XX percentage separation between the two peaks.

If I remember correctly, a resolution of 2.0 indicates 100% separation of the peaks.

I don't remember what 1.5 resolution gives, but it is in the upper 90s percentile.

Rod

Thank you Mr.Rod some of my senior told me before 7 or 8 years 1.2 resolution is 97% separation still i not got any mathamatical explanantion or any equation i am searching answer for this question for more than 5 years. Thank you for your explanantion.

Look through books discussing the theory of chromatography. Remember we are discussing the THEORETICAL separation of two IDEAL peaks, nothing necessarily of reality.

The mathematics are available. Perhaps someone may be able to direct you to the best tome available. I am sure a brief trip to the library or a quick search of the internet will give you all the information you need.

best wishes,

Rodney George

Many textbooks state that "baseline" resolution is Rs = 1.5. More accurately, that is "99% baseline resolution".

Resolution is the ratio of center-to-center separation divided by baseline width.

For a perfectly Gausian peak, the baseline width is 4σ. Therefore:

Rs = 1.0 is a 4σ separation
Rs = 1.5 is a 6σ separation
Rs = 2.0 is an 8σ separation

You can go to any statistics textbook and find tables of the percent of the peak area encompassed within a particular range of σ values. From memory, +/-2σ accounts for 95% of the area, and +/-3σ accounts for 99% of the area. for two equal-sized, Gaussian peaks, at Rs = 1.0, you are 2σ out from the center of each peak, so you have a 5% mutual overlap. At Rs = 1.5, you are 3σ out, so you have a 1% mutual overlap -- hence "99% baseline resolution". You can look up the appropriate values for any other resolution.

All of that said, Rod is exactly right:

Remember we are discussing the THEORETICAL separation of two IDEAL peaks, nothing necessarily of reality.

Thank you for your explanation Mr. Tom. Sure i will refer

We used many times the TrennZahl which basically give you a value for the number if peaks that "fit" between two eluting peaks. it uses the difference in retention time and the peak widths at half height for both peaks. This was very easy to calculate.

Hi Mr. jdezeeuw can you tell me how to calculate with an example?

Hi Mr. jdezeeuw can you tell me how to calculate with an example?

If Jaap doesn't mind , here is a link:

http://tinyurl.com/cfvkob9