How to do the software validation.
I'm doing by taking a print out of the chromatogram and drawing the tangents, peak width at % level and measuring through scale and calculating the tailing, plates and resoltuion. But, my question is how to draw the tangents, at what point on the peak we have to draw and at what angle to the base line. Do any body can suggest me any good method or any www links.
advance thanks.

Look in your softwares help page. There are many ways to calculate tailing and resolution. When you would validate your software this way, you have to be sure that you use the same method of calculation.

yes, and thank you.
I have gone through agilent an dfound the tangents being drawn at the inflexion points, where as the waters software drawing the tangents at % level (say 61%). What actually USP says.

same thing for a peak that does not tail

good

Do it means that the USP tells to draw the tangemts at 61%,?
Do the results of the plates differ by below two methods.
1. Drawing the tangent at 61%.
2. Drawing the tangent at inflexion pint
considering the peak tails.

pl guide ?

Nobody cares what the USP says. You want to validate your software. Look how your software does it, and then do the same thing manually. If you get about the same results, you have validated your software. Let your software company argue with USP about how to do plates!

THANKS A LOT!!

One needs validate the software by using Theoritical calculations applying to the software based programmes. Like let us say theoritical plates by drawing the tangents and applying the peak width and other things and the reported values by the system. If u are close to the system values by user set limits and if it is justified that's it. You validated your software.