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.
A series of N-trifluoroacetyl/pentafluoropropionyl-O-trifluoroethyl/ pentafluoropropyl/heptafluorobutyl ester derivatives of 5-methoxyindole-3-acetic acid (5MIAA) were synthesized. Under electron-capture negative ionization conditions, the N-trifluoroacetyl derivatives were found to yield relatively abundant, analyte-specific M-. molecular ions and [M-HF]-., [M-HF-CF2CO]-. and [M-CF3CO]- fragment ions, while the N-pentafluoropropionyl derivatives yielded predominantly the reagent-specific pentafluoroacylium C2F5CO- ion. 5-[2H3]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-O-pentafluoropropyl ester derivative, femtomole to low picomole per gland/organ per g ml-1 levels of endogenous 5MIAA were identified and determined in the rat pineal gland, retina, whole brain and serum.
Li
P
P
Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Kowloon, Hong Kong.
Wong
K L
KL
Kwan
M C
MC
Tsang
C W
CW
Pang
S F
SF
D000818:Animals; D001923:Brain Chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006897:Hydroxyindoleacetic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D007202:Indicators and Reagents; D007211:Indoles / Q000737:chemistry*; D008297:Male; D010870:Pineal Gland / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000737:chemistry
D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D007211:Indoles; C001736:5-methoxyindoleacetic acid; D006897:Hydroxyindoleacetic Acid