How to Calculate Mass Spec
What is Mass Spec?
Mass spectrometry measures mass-to-charge ratios (m/z) of ions; determines molecular weight and fragment composition.
Step-by-Step Guide
- 1Input mass spectrum peaks and intensities
- 2Identify molecular ion, fragments, and base peak
- 3Determine molecular structure
Worked Examples
Input
Molecular ion m/z = 88, base peak m/z = 73 (M-15, loss of CH₃)
Result
Suggests methyl group loss
Common Mistakes to Avoid
- ✕Misidentifying molecular ion (not always M⁺)
- ✕Not accounting for isotope patterns
Frequently Asked Questions
What's base peak?
Most intense peak; usually stable fragment ion; useful for structure determination.
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