Mass Spectrum Analyzer Calculator

Enter Spectrum Inputs

The page uses a single-column flow overall, while the calculator fields switch to three columns on large screens, two on smaller screens, and one on mobile.

Neutral Mass (Da)

Monoisotopic or average neutral analyte mass.

Total Adduct Mass (Da)

Use the total added ionizing mass.

Charge State (z)

Use positive or negative integer magnitude.

Measured m/z

Observed centroid or fitted peak position.

Peak Width Δm

Full width at half maximum in m/z units.

Reference m/z

Calibration reference for ppm comparison.

Flight Length (m)

Useful for time-of-flight estimation.

Accelerating Voltage (V)

Potential difference applied to the ion.

Base Intensity (%)

Controls the simulated cluster height.

Isotope Peaks to Simulate

Choose between 2 and 10 peaks.

Example Data Table

Sample	Neutral Mass (Da)	Adduct Mass (Da)	z	Measured m/z	Peak Width	Voltage (V)	Flight Length (m)
Glucose + H	180.06339	1.007276	1	181.07066	0.0500	3500	1.20
Peptide + 2H	998.45120	2.014552	2	500.23290	0.0180	4000	1.50
Small drug + Na	304.12080	22.989218	1	327.10970	0.0300	3000	1.10

Formula Used

Theoretical m/z = (Neutral Mass + Total Adduct Mass) / |z|
Reconstructed Neutral Mass = (Measured m/z × |z|) − Total Adduct Mass
Mass Error (Da) = Measured m/z − Theoretical m/z
Mass Error (ppm) = [(Measured m/z − Theoretical m/z) / Theoretical m/z] × 1,000,000
Calibration Error (ppm) = [(Measured m/z − Reference m/z) / Reference m/z] × 1,000,000
Resolving Power = m / Δm
Isotope Spacing ≈ 1 / |z|
Ion Velocity = √[(2qV) / m]
Time of Flight = Flight Length / Ion Velocity

How to Use This Calculator

Enter the neutral mass of the analyte in daltons.
Add the total adduct mass added during ionization.
Specify the charge state magnitude of the detected ion.
Enter the measured m/z taken from your spectrum.
Provide the peak width for resolving power estimation.
Fill in the reference m/z if calibration comparison matters.
Add flight length and accelerating voltage for time-of-flight estimates.
Choose the number of isotope peaks and a base intensity.
Click Analyze Spectrum to show the results above the form.
Use the CSV or PDF buttons to export the calculated summary.

FAQs

1. What does this calculator analyze?

It estimates theoretical m/z, reconstructed neutral mass, mass error, isotope spacing, resolving power, ion velocity, time of flight, and calibration drift from your entered spectral data.

2. Why is charge state important?

Charge state directly changes m/z and isotope spacing. A doubly charged ion halves m/z relative to the same singly charged ion and narrows peak spacing.

3. What should I enter as adduct mass?

Enter the total ionizing mass added to the neutral analyte. For example, use one proton mass for [M+H]+ or a sodium mass for [M+Na]+.

4. How is resolving power interpreted?

Resolving power compares peak position with peak width. Larger values indicate a better ability to separate nearby ions and distinguish overlapping signals.

5. What does ppm error tell me?

PPM error shows how far the observed m/z drifts from the theoretical or reference value on a relative scale. Smaller absolute values indicate better mass accuracy.

6. Is the isotopic graph a real spectrum?

No. It is a simulated cluster built from your measured peak, spacing, width, and intensity assumptions. It helps visualize expected peak grouping patterns.

7. Can this help with time-of-flight instruments?

Yes. When you enter flight length and accelerating voltage, the calculator estimates velocity and flight time using classical ion acceleration relationships.

8. Does it support negative ions?

Yes. The formulas use the magnitude of charge for spacing and energy calculations. Enter the appropriate adduct mass and charge magnitude for your mode.