Charge state

Definition

The number of charges an ion carries, written as [M+nH]ⁿ⁺ for a peptide that has picked up n protons. A peptide typically appears as a series of charge states rather than a single line.

Related terms

Deconvolution

The calculation that recovers a single molecular mass from a series of charge states.

Electrospray ionisation

A soft ionisation technique that transfers molecules from solution into the gas phase as charged ions without breaking them apart.

About mass spectrometry

Terms a reader meets on mass-spectrometric reports from other laboratories, and on confirmatory work sent out. This laboratory has no in-house mass spectrometer, and its certificates carry no mass spectrum.

Mass-to-charge ratioObserved massTheoretical massMass accuracyIsotope patternIon suppressionIsobaricStereoisomerRetro-inverso peptide

Read more

• Purity versus identity
• Peptide identity testing
• The full peptide testing glossary