title: Quantitative chiral analysis of phthaloylglutamic acid and related analogs by a single ratio kinetic method using electrospray ionization and matrix-assisted laser desorption techniques.
abstract: A rapid method for quantitative chiral analysis of phthaloylglutamic acid and its dimethyl ester by Cook's kinetic method is demonstrated using electrospray ionization (ESI) and matrix-assisted laser desorption techniques. Transition-metal-bound complex ions containing the chiral phthaloylglutamic acid and its dimethyl ester are generated by ESI mass spectrometry and subjected to collision-induced dissociation. The ratio of the two competitive dissociation rates is related to the enantiomeric composition of the drug mixture. A seven-point calibration curve, derived from the kinetic method, allowed rapid quantitation of the enantiomeric excess of drug mixtures. In this paper, matrix-assisted laser desorption/ionization (MALDI) coupled with the linear ion trap (LIT) technique is evaluated for its applicability as a complementary technique to ESI for chiral discrimination and quantitation.
authors.affiliation: Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA. sramagir@utmen.edu
authors.forename: Suma
authors.initials: S
authors.lastname: Ramagiri
authors.forename: Renuka
authors.initials: R
authors.lastname: Gupte
authors.forename: Igor
authors.initials: I
authors.lastname: Rakov
authors.forename: Charles R
authors.initials: CR
authors.lastname: Yates
authors.forename: Duane D
authors.initials: DD
authors.lastname: Miller
mesh_terms: D005971:Glutamates / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D005971:Glutamates; C034741:N-phthaloylglutamic acid