Figure 6.

Using isotopic abundance patterns to count the number of chlorine atoms in a C₁₂ compound: at each individual mass fragment, exact mass can be further investigated to confirm the chemical formula. Chlorine has an abundance of A + 2 isotopes of ~25%, so a spacing at 1.997 375 78 Da with relative abundance of ~25% indicates 1 chlorine, 63% indicates 2 chlorines, 100% indicates 3 chlorines, etc. The spacing of A+1 at 1.003 354 84 Da, and the relative abundance at ~12%indicates 12 carbons.