A high‐specificity aniline‐based mass tag for aldehyde detection. (17th June 2022)

• Record Type: Journal Article
• Authors: Mungalachetty, Prisca; Kulkarni, Pushkar; Wang, Poguang; Giese, Roger
• Is Part Of: Rapid communications in mass spectrometry. Volume 36:Number 15(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-17
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.9322
• Languages: English
• ISSNs: 0951-4198

Abstract

Abstract : Rationale: We studied an aldehyde‐labeling reagent, N ‐{2‐[(4‐aminophenoxy)methyl]benzyl}‐ N, N ‐diethylethanaminium bromide (CAX‐A), containing an aniline functional group for the detection of aldehydes with high specificity. Methods: Six standard aldehydes were labeled by CAX‐A and analyzed using LC‐ESI‐Orbitrap‐MS. The aldehydes (each 40 nmol) were derivatized with CAX‐A in the presence of sodium cyanoborohydride at room temperature overnight. The labeling reaction was applied to two urine samples for the detection of putative aldehydes. Results: All six standard CAX‐aldehyde derivatives were detected as precursor ions by dilution to 830 fmol/injection (signal‐to‐noise [S/N] ratio 587–1573). A total of 2184 MS1 features were detected overall in urine and blanks, of which 14 were putative aldehydes found only in urine. Conclusions: CAX‐A can provide three levels of specificity for aldehyde detection. First is the known labeling specificity of the aniline functional group for aldehydes, which we confirmed here by observing a significant peak only from the aldehyde (S/N = 3388) when a mixture of an aldehyde, a ketone (no peak), and a quinone (S/N = 2.3) was tested. Second is the ease of formation of an analyte‐characteristic first product ion (via anchimeric‐assisted loss of triethylamine as a neutral) in MS2 from a CAX‐labeled analyte. Third is the formation of a characteristic second product ion via loss of CO in MS3. CAX‐A enables the specific, convenient detection of putative aldehydes in urine.