Kostenloser Isotope Pattern Rechner
Schätzen Sie M+1 und M+2 isotope peak intensities aus molecular formula for mass spectrometry interpretation.
M+1 Relative Intensity
12.07 %
M+1 Relative Intensity vs Number of Carbons
Formel
## Isotope Pattern Estimation The natural isotope distribution creates characteristic patterns in mass spectra. The M+1 and M+2 peaks relative to the monoisotopic (M) peak help identify molecular formulas. ### Approximate Rules M+1 contributions per atom: C = 1.1%, H = 0.015%, N = 0.37%, O = 0.04%, S = 0.8% M+2 contributions: O = 0.20% each, S = 4.4% each, plus (M+1)²/200 These are approximations. Accurate patterns require full combinatorial calculation, especially for chlorine and bromine-containing compounds.
Lösungsbeispiel
Estimate isotope pattern for C10H14N2O3.
- 01M+1 = 10×1.1 + 14×0.015 + 2×0.37 + 3×0.04 = 11.0 + 0.21 + 0.74 + 0.12 = 12.07%
- 02M+2 = 12.07²/200 + 3×0.20 = 0.73 + 0.60 = 1.33%
Häufig Gestellte Fragen
Why are isotope patterns useful?
Isotope patterns provide complementary information to exact mass. Two formulas with similar masses may have very different isotope patterns. Chlorine and bromine create distinctive doublet and triplet patterns.
How do Cl and Br affect isotope patterns?
Cl has 75.8% Cl-35 and 24.2% Cl-37 (M+2 = ~32% per Cl). Br has 50.7% Br-79 and 49.3% Br-81 (nearly equal M and M+2). These create unmistakable patterns even at low resolution.
When does this approximation break down?
For large molecules (proteins, polymers), the monoisotopic peak may not be the most abundant. For Cl/Br compounds, exact binomial calculations are needed. Use dedicated software for accurate predictions.
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