Parent and Neutral Loss Monitoring on a Quadrupole Ion Trap Mass Spectrometer:  Screening of Acylcarnitines in Complex Mixtures

• Published in: Analytical chemistry (Washington) 2002-11, Vol.74 (22), p.5799-5806
• Main Authors: McClellan, Joseph E, Quarmby, Scott T, Yost, Richard A
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Ions; Scientific imaging; Spectrometric and optical methods
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac026073d

A novel and practical technique for performing both parent and neutral loss (P&NL) monitoring experiments on a quadrupole ion trap mass spectrometer is presented. This technique is capable of performing scans analogous to the parent and neutral loss scans routinely applied on tandem-in-space instruments and allows for the screening of a sample to detect analytes of a specific compound class on a chromatographic time-scale. Acylcarnitines were chosen as the model compound class to demonstrate the analytical utility of P&NL monitoring because of their amenability to electrospray ionization (ESI), their unique and informative MS/MS fragmentation pattern, and their importance in biological functions. The [M + H]+ ions of all acylcarnitines dissociate to produce neutral losses of 59 and 161 amu and common product ions at m/z 60, 85, and 144. Both the neutral loss monitoring of 59 amu and the parent ion monitoring of m/z 85 are shown to be capable of identifying acylcarnitine [M + H]+ ions in a synthetic mixture and spiked pig plasma. The neutral loss monitoring of 59 amu is successful in detecting acylcarnitines in an unspiked pig plasma sample.