Reaction of cyclohexanone with [NH₄]⁺ under chemical ionization conditions. 1—formation of protonated unsubstituted imines

Mass spectrometry of isomeric fatty acid hydroperoxides by chemical ionization via direct exposure probe

“…Rather, it either arises from loss of water from the adduct ion or the loss of water from an ammoniation reaction product in the gas plasma. Similar reactions are reported to occur (7,8) with ketones forming imines in the CI source. Of those ions tested for daughter spectra, those from m/z 328 probably are the best we have examined for giving a distinctly different spectrum for each of the hydroperoxide isomers.…”

“…It is not readily apparent whether these fragments are the unprotonated C9:1 and C12:1 aldehydes from heterolysis or whether they arise from a more complex route from an 9 ammoniation reaction occurring in the CI plasma. Similar amines are reported to form from ketones in the CI source (7,8). MS/MS experiments with CAD daughters of isomeric high mass fragments from hydroperoxides may prove useful in directly identifying and quantitating the hydroperoxide isomers in samples that have not been rigorously purified.…”

Sodium ion attachment reactions in an ion trap mass spectrometer

“…33 Beside pyrolytic processes, these frangible compounds bearing nitro groups can be subject to reduction reactions yielding amino by‐products which are observed under high‐pressure chemical ionization conditions 34,. 35 Reduction of nitro (NO 2 ) groups into amino (NH 2 ) groups has been reported for similar compounds and it is well‐known that this reaction occurs under certain ionization conditions 34–37. Under sodium attachment reaction conditions, RDX forms an [M + Na + ] adduct ( m/z 245) and a few other mass peaks (Fig.…”

Neutral reactions in gas chromatography/chemical ionization mass spectrometry

“…With ammonia as a GC carrier gas, acetophenone forms an imine in a condensation reaction in the gas chromatograph C6H5COCH3 + NH3 -C6H5C(NH)CH3 + H20 (1) The imine elutes from the column and is protonated in the ion source to give m/z 120 as the major ion in the spectrum NH4(NH3)/ + C6H5C(NH)CH3 -* C6H5C(NH2)CH3+ +(x + 1)NH3 (2) Precise mass measurements show that the ion at m/z 120 in these experiments is C8H10N+, not the molecular ion for acetophenone, C8H80+. Not all of the acetophenone is converted to the imine and the unreacted acetophenone elutes and forms an adduct ion, ( + NH4)+, at m/z 138.…”