Compound

Deprotonated Form

Molecular formula

m/z (theoretical)

m/z (experimental)

Indigo Carmine

[C₁₆H₈N₂O₈S₂]²⁻

209.9861

209.9829

2

[C₇H₆NO₅S]⁻

215.9967

215.9881

3

[NaSO₄]⁻

118.9415

118.9419