Fig. 2.

A, Trapezoidal quantitation can produce poor measurements with only five points (or fewer). B, Error (shaded in blue) in trapezoidal quantitation (red dashed lines) typically cancel out when measuring a Gaussian peak (black solid line) with eight to nine points across the peak. C, The average percent deviation with 95% error bars in actual/calculated area at different number of points across a Gaussian peak. The shaded regions indicate poorly quantified peptides with 5 or fewer transitions (red), moderately quantified peptides with between 6 and 8 transitions (yellow), and well quantified peptides with 9 or more transitions (green).