Hi There, I was wondering if there any function that would give me the start and end points of a Peak. I have absorbance values from the chromatogram and i have the retention time of each peak but i want to find the start and end points of peak. I need that to find the area under each Peak. I trying to make the process of finding the area under the curve automated so trying to approximate the star and end point by looking at the graph wont help me. If there is no function a little background of finding the start and end points would be helpful. Thanks Ramya -- View this message in context: http://r.789695.n4.nabble.com/Start-and-end-point-of-peak-tp3313836p3313836.html Sent from the R help mailing list archive at Nabble.com.