Dear Haraeendran, please be more specific !

Harry , endogenous levels are substracted after takining mean area of the available interference in the blank runs, means area is subtracted, and it can be manually plotted with a validated excel, also the endogeous level should be a constant and specific with different lots

I agree with Rajen, but the concnetration of endogenous substance may or may not be constant and it depends on the compound we are analysing. As some hormone and inorganic compounds show variation due to some inherent feed back mechanism. A minimum of 3-5 baseline values would suffice the baseline correction.