H/C atomic ratios of the 35 considered analyses of the cometary particles arranged by alphabetic order. For each analysis (i.e., horizontal line), the red and blue points correspond to the H/C values obtained with the calibration curves (from positive- and negative-mass spectra, respectively). The two vertical lines represent the averages of the H/C atomic ratio for the two modes, the red and blue color bands are the associated 1σ standard deviations.