Isotope Distribution Calculator

Isotope distribution refers to the pattern of peaks in a mass spectrum caused by the natural occurrence of different isotopes of elements in a molecule. Each isotope has a slightly different mass, creating multiple peaks for the same compound.

The monoisotopic peak represents the mass of the molecule containing only the most abundant isotopes. Additional peaks show the masses when one or more atoms are replaced by heavier isotopes, with their relative abundances based on natural isotope ratios.

High resolution provides more accurate mass calculations and can distinguish between closely spaced peaks. Low resolution is faster to calculate and approximates what you might see on lower-resolution instruments like quadrupole mass spectrometers.

Lower abundance thresholds show more isotope peaks but may include very weak signals that could be noise in real experiments. Higher thresholds focus on the most significant peaks that are likely to be observed experimentally.

The calculations use precise atomic masses from NIST data and are highly accurate for theoretical predictions. Real experimental masses may vary slightly due to instrument calibration and resolution limitations.

Yes, you can specify positive or negative charge states. The calculator will adjust the m/z values accordingly by adding or removing the appropriate number of electrons from the molecular mass.

The calculator supports standard chemical notation including common elements like C, H, N, O, S, P, and halogens. Use format like C6H12O6 for glucose or C2H6O for ethanol.

For larger molecules like proteins, focus on the molecular weight and average mass calculations. The isotope pattern becomes very complex for large molecules, so consider using charge state analysis for multiply charged ions.