Native Mass Spectrometry Calculator

In native mass spectrometry, proteins and complexes retain their natural charge states, and converting between molecular mass, charge state (z), and m/z value is a routine but error-prone calculation. The Native Mass Spectrometry Calculator handles all three directions: select your calculation type — m/z from mass and charge, mass from m/z and charge, or charge from mass and m/z — then enter the known values to get your primary result alongside a secondary cross-check and mass per charge unit. You can also apply an adduct correction (e.g., H⁺ or Na⁺) for more precise results.

Da
Da

Mass of adduct ion (e.g., 1.0078 for H+, 22.9898 for Na+)

Results

Primary Result

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Secondary Calculation

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Mass per Charge Unit

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Frequently Asked Questions

What is native mass spectrometry?

Native mass spectrometry is a technique that analyzes biomolecules in their native, folded state under non-denaturing conditions. It preserves protein complexes and non-covalent interactions, allowing measurement of intact molecular masses.

How do I calculate m/z from molecular mass and charge?

The m/z ratio is calculated by dividing the molecular mass by the charge state: m/z = (Mass + z × Adduct Mass) / z, where z is the charge state and adduct mass accounts for ionization (typically 1.0078 Da for H+).

What charge states are typical in native MS?

Native MS typically produces lower charge states compared to denaturing conditions. Proteins often show charge states between +5 to +30, depending on their size, with larger proteins generally having higher charge states.

Why is adduct mass correction important?

Adduct mass correction accounts for the mass of ionizing species (like H+, Na+, or NH4+) that attach to the molecule during ionization. This correction is essential for accurate mass determination from m/z measurements.

How accurate are native MS mass measurements?

Native MS can achieve mass accuracy within 0.01-0.1% for well-resolved peaks. The accuracy depends on instrument calibration, resolution, and the complexity of the charge state distribution.

What is the relationship between charge state and m/z?

Higher charge states result in lower m/z values for the same molecule. Multiple charge states of the same molecule appear as a series of peaks with predictable m/z spacing, allowing charge state determination.