🏠 Home / By Experiment / Structure Identification / Mass Spectrometry (MS) 中文 EN
⚖️ Structure Identification · Method

Mass Spectrometry (MS)

Weigh the molecule and pin down the formula
🎯 Difficulty ★★☆ Medium Duration About 30 min–1 h 🎯 Use Determine molecular mass and fragments to confirm structure, formula, and purity.
📖 Principle
Ionize the molecule and weigh each ion by its mass-to-charge ratio.
Below are 4 steps. Open each to see how to do it and add products to your shared list.

📋 Workflow

Full workflow, products add-to-cart directly
1

Sample preparation

10 min
Prepare at suitable concentration in an ionizable solvent; choose inlet for the ionization mode.
💡 Tip Use low concentration in ESI to avoid agglomeration
⚠️ Caution Salts/surfactants suppress ionization
🧪 Materials for this step (click to shop by spec/brand)
2

Choose the ionization mode

10 min
Select ESI/APCI/MALDI by polarity; use positive mode for basic compounds.
💡 Tip Use APCI or EI for neutral/nonpolar analytes
⚠️ Caution High salt fouls the ESI source
🧪 Materials for this step (click to shop by spec/brand)
3

Acquire data

15–30 min
After tuning, acquire full scan for the molecular ion, add MS/MS fragments as needed.
💡 Tip HRMS confirms the exact formula
⚠️ Caution Don't mistake Na⁺/K⁺ adducts for the molecular ion
🧪 Materials for this step (click to shop by spec/brand)
4

Interpret spectra

15 min
Identify molecular ion, isotope pattern, and key fragments to propose a structure.
💡 Tip Isotope patterns reveal Cl/Br/S content
⚠️ Caution Fragment assignment needs structural chemistry judgment
🧪 Materials for this step (click to shop by spec/brand)

⚠️ 5 Common Beginner Mistakes

  • Misreading adducts as the molecular ion
  • Fouled source drifts the signal
  • Over-concentration gives dimers
  • No tuning makes masses inaccurate
  • Ignoring isotope patterns misses halogens

❓ FAQ

+How to confirm formula?
Fit exact HRMS mass and isotope pattern to elements.
+ESI or APCI?
ESI for polar/thermolabile; APCI for mid-polar thermally stable.
+Can MS judge purity?
It helps, but quantitative purity needs LC-MS or HPLC.

🧾 My Cart

Items selected on the product page are shared here
Nothing added yet
🛒 Go to Products
Data authenticity: Product categories from JW Supply Chain standard taxonomy; method→step→product connected. Last updated: 2026-08-23 · v3.0