Related Experiment Video
Updated: Aug 9, 2026

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes
Published on: April 1, 2013
Collisional activation mass spectra of M-. ions of azo dyes containing 2-naphthol
W C Brumley1, G M Brilis, R J Calvey
1US Environmental Protection Agency, Environmental Monitoring Systems Laboratory, Las Vegas, Nevada 89193.
Abstract:
Collisionally activated decomposition mass spectra of M-. ions of azo dyes are presented. The compounds are of general structure Ar(1)--N = N--Ar(2), where Ar(1) is substituted phenyl and Ar(2) is 2-naphthol. Characteristic fragment ions observed include m/z 157, which corresponds to the 2-naphthol substituent with cleavage of the--N = N--bond represented as [Ar(2)--N]-.. Ion of general structure [Ar(1)--NH]- are also observed. Parent ion scans of m/z 157 provide a potential screening technique for 2-naphthol-containing axo dyes. Specific results are reported for the chloroform extract of FD&C Red #8, and capillary gas chromatographic introduction is compared with direct exposure probe introduction for the identification of dyes.
Related Concept Videos
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Mass Spectrometry of Amines
Mass Spectrometry: Aromatic Compound Fragmentation
Mass Spectrometry: Amine Fragmentation
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
Cycloaddition Reactions: MO Requirements for Photochemical Activation

