Automated determination of neuroactive acidic sulphur-containing amino acids and gamma-glutamyl peptides using liquid chromatography with fluorescence and electrochemical detection.
A column liquid chromatographic method is presented for the determination of trace levels of acidic sulphur-containing amino acids and gamma-glutamyl di- and tripeptides in microdialysates sampled from rat brain in vivo. Automated precolumn derivatization was performed with o-phthaldialdehyde-beta-mercaptoethanol. The derivatives were separated by reversed-phase liquid chromatography with electrochemical and fluorescence detection. The mean relative standard deviation (n = 10) was 1.03 and 4.59% for retention times and peak heights, respectively. The mean correlation coefficient of linearity (r) was 0.9982 in the range 4.5-450 pmol (n = 15), and the lowest detectable amount was 200 fmol for the homocysteinesulphinic acid derivative, (k' = 5.4, at a signal-to-noise ratio of 3). A microcolumn electrochemical detection method, developed for volume-limited samples, produced a fifteen-fold increase in mass sensitivity. Neurochemical applications using microdialysis in vivo are presented.
Orwar
O
O
Department of Analytical and Marine Chemistry, Chalmers University of Technology, Gothenberg, Sweden.
Folestad
S
S
Einarsson
S
S
Andiné
P
P
Sandberg
M
M
D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D004151:Dipeptides / Q000032:analysis; D005973:Glutamine / Q000031:analogs & derivatives*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008832:Microchemistry; D009842:Oligopeptides / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013455:Sulfur / Q000032:analysis*
D000596:Amino Acids; D004151:Dipeptides; D009842:Oligopeptides; D005973:Glutamine; D013455:Sulfur