Evaluation of Fluorinated Indole Derivatives for Electron-capture Negative Ionization Mass Spectrometry: Application to the Measurement of Endogenous 5-Methoxyindole-3-Acetic Acid in Rat

✍ Scribed by Li, P.; Wong, K. L.; Kwan, Miranda C. Y.; Tsang, C. W.; Pang, S.F.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 734 KB
• Volume: 31
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199611)31:11<1228::aid-jms411>3.0.co;2-1

✦ Synopsis

A series of N-trifluoroacetyl/pentafluoropropionyl-O-trifluoroethyl/~ntafluoropropyl/heptafluorobutyl ester derivatives of 5-methoxyindole-3-acetic acid (SMIAA) were synthesized. Under electroncapture negative ionization conditions, the N-trifluoroacetyl derivatives were found to yield relatively abundant, analyte-specific M-' molecular ions and [M-HFI-', [M-HF-CF,CO]-' and IM-CF,CO]-fragment ions, white the Npentafluoropropionyl derivatives yielded predominantly the reagent-specific pentafluoroacylium C,F,CO-ion. 5-I 'H,] Methoxyindole-3-acetic acid was prepared in high yield by a new synthetic procedure and used as the internal standard in subsequent gas chromatographic/mass spectrometric analysis. Using the N-trifluoroacetyl-0pentafluoropropyl ester derivative, femtomole to low picomole per gland/organ per g ml-l levels of endogenous SMIAA were identified and determined in the rat pineal gland, retina, whole brain and serum.