Time of Flight Mass Spectrometry Guide
Time of flight mass spectrometry measures how long ions need to cross a known field free path. The idea is simple. Light ions travel faster. Heavy ions travel slower. The method becomes powerful when voltage, path length, and calibration delay are controlled.
Why Flight Time Matters
A sample is ionized first. Each ion is then accelerated by an electric potential. Ions with the same charge receive the same energy. Their speed depends on mass. The detector records arrival time. That time is converted into mass to charge ratio. This calculator follows that workflow. It can solve for time, mass to charge ratio, voltage, or path length.
Advanced Inputs
Real instruments include delays and effective paths. A reflectron can increase the useful travel distance. Cables and electronics can add a time offset. The form includes both adjustments. You may enter a multiplier for the effective path. You may also subtract a known time zero delay. These values help match instrument behavior.
Uncertainty and Review
The calculator also estimates relative uncertainty. It uses the main sensitivity terms from the square root relation. Length errors affect flight time directly. Voltage and mass errors enter with half weight during time prediction. For reverse calculations, timing and length errors can have doubled effect. This quick estimate is useful for checks. It is not a replacement for a full validation study.
Practical Use
Use calibrated values whenever possible. Enter standards that bracket the unknown peak. Keep units consistent. The tool converts common units internally. Review the velocity and kinetic energy. They can reveal unrealistic entries. Very high velocity may mean an incorrect unit. Very low voltage may also distort the result.
Reporting Results
The output table gives the final value and supporting details. It lists effective distance, net time, velocity, mass, and uncertainty. Use the CSV download for spreadsheets. Use the PDF download for lab notes. The example table shows common starting values. Always compare the result with instrument calibration records.
During method development, repeat calculations for several charge states. This helps identify overlapping peaks. It also supports sanity checks before acquisition. Save exported files with sample names, dates, and operator notes for future traceability. This supports audit review later.