Comparison of different amino acid derivatives and analysis of rat brain microdialysates by liquid chromatography tandem mass spectrometry.
The efficiencies of three derivatisation reagents that react with either the amine (9-fluorenylmethyl chloroformate (FMOC)) or the carboxylic acid group (butanol) of amino acid or with both types of functional groups (propyl chloroformate) were compared in the analysis of amino acids by liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Separation of 20 amino acids derivatised with these three reagents was studied on reversed-phase chromatography. Linearity, repeatability and limits of detection of the LC-ESI-MS/MS method were determined by analysing FMOC-, butanol- and propyl chloroformate-derivatised lysine, beta-aminobutyric acid, threonine and glutamic acid. The limits of detection for the derivatised amino acids (7.5-75fmol) were as much as 2-60 times lower than those of the corresponding underivatised molecules. The best linearity was observed for amino acids derivatised with propyl chloroformate or butanol (r(2)=0.996-0.999, range=100-8500nmolL(-1)). Propyl chloroformate was the best suited of the reagents tested for the analysis of amino acids with LC-MS/MS and was used for the analysis of amino acids in rat brain microdialysis samples.
Uutela
Päivi
P
Faculty of Pharmacy, Division of Pharmaceutical Chemistry, P.O. Box 56, FI-00014 University of Helsinki, Finland.
Ketola
Raimo A
RA
Piepponen
Petteri
P
Kostiainen
Risto
R
D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D001923:Brain Chemistry; D000440:Butanols / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D005449:Fluorenes / Q000737:chemistry; D005561:Formates / Q000737:chemistry; D008297:Male; D017551:Microdialysis; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
D000596:Amino Acids; D000440:Butanols; D005449:Fluorenes; D005561:Formates; C054007:1-(9-fluorenyl)methyl chloroformate; C538931:propyl chloroformate