Differentiation of epimeric mono- and dihydroxypipecolic acids by negative ion sequential mass spectrometry

✍ Scribed by Geoffrey C. Kite

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 52 KB
• Volume: 13
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19990615)13:11<1063::aid-rcm609>3.0.co;2-f

✦ Synopsis

Sequential mass spectrometry (MS/MS) using an atmospheric pressure chemical ionization (APCI) source is a useful technique for the identification of the epimeric mono-and dihydroxypipecolic acids that occur naturally in plants. In negative ion mode, the collision induced dissociation (CID) spectra of the two 4-hydroxypipecolic acid epimers, the two 5-hydroxypipecolic acid epimers and two of the four 4,5dihydroxypipecolic acid epimers were all different. In positive ion mode, only two monohydroxypipecolic acids and one dihydroxypipecolic acid could be distinguished from their CID spectra. The two dihydroxypipecolic acid epimers not resolved from negative ion MS/MS could be separated by prior high-performance liquid chromatography (LC). In a mixture of all eight hydroxypipecolic acids, six could be identified by negative ion LC/MS/MS. The two unresolved dihydroxypipecolic acids co-eluted and did not produce suitably characteristic fragment ions for single product ion monitoring.