The .fit_peaks method returns a Pandas DataFrame [Figure (C)] which reports the best-fit values for each parameter for each peak. Importantly, it also returns the integral of Equation for each compound over a given time window which is linearly proportional to the concentration of the analyte . Figure ) demonstrates that the peak quantification algorithm of hplc-py yields a linear relationship between concentration and integrated area for a standard curve of a lactose sugar solution across a decade of concentrations.