1. What is Monoisotopic Mass?

The monoisotopic mass is the sum of the masses of the atoms in a molecule using the most abundant isotope of each element. It's particularly important in mass spectrometry for identifying molecular ions.

2. How Does the Calculator Work?

The calculator uses the following principle:

Where:

• Each element's contribution is its lightest stable isotope mass multiplied by its count in the formula
• Common elements and their monoisotopic masses are predefined in the calculator

Explanation: The calculator parses the chemical formula, identifies each element and its count, then sums the masses of the lightest isotopes.

3. Importance in Mass Spectrometry

Details: Monoisotopic mass is crucial for interpreting mass spectra, as it corresponds to the most intense peak in the isotopic cluster for small molecules.

4. Using the Calculator

Tips: Enter chemical formula using standard notation (e.g., C6H12O6 for glucose). Case matters - element symbols start with uppercase letters.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between monoisotopic and average mass?
A: Monoisotopic uses the lightest isotope of each element, while average mass considers natural isotopic abundance.

Q2: Why is monoisotopic mass important in MS?
A: For small molecules, the monoisotopic peak is typically the most intense, making it the reference point for mass measurements.

Q3: What elements are supported by this calculator?
A: H, C, N, O, P, S, F, Cl, Br, I. Others can be added by modifying the isotope table.

Q4: How accurate is this calculation?
A: It uses standard monoisotopic masses with 6 decimal places, suitable for most MS applications.

Q5: Can I use this for peptides/proteins?
A: While it works, specialized tools that consider amino acid residues might be more convenient for biomolecules.