Artifact-free matrix-assisted laser desorption ionization time-of-flight mass spectra of tert.-butyldimethylsilyl ether derivatives of cyclodextrins used for the synthesis of single-isomer, chiral resolving agents for capillary electrophoresis.
Artifact-free, high-resolution matrix-assisted laser desorption ionization (MALDI) time-of-flight mass spectra have been obtained for the labile, single-isomer, tert.-butyldimethylsilyl ether derivatives of alpha-, beta- and gamma-cyclodextrins by optimizing the MALDI sample preparation method. 2,5-Dihydroxybenzoic acid, a 3:1 mixture of 2,5-dihydroxybenzoic acid and 1-hydroxyisoquinoline, and 2,4,6-trihydroxyacetophenone were investigated as MALDI matrices with methanol and acetonitrile as matrix solvents. Partial-to-complete loss of the tert.-butyldimethylsilyl groups was observed when the commonly used 2,5-dihydroxybenzoic acid was the MALDI matrix and/or methanol was the solvent, both with and without trifluoroacetic acid as additive. Loss of the labile tert.-butyldimethylsilyl groups was avoided with 2,4,6-trihydroxyacetophenone as MALDI matrix and acetonitrile as matrix solvent. Good ion intensities were achieved for the (M+Na)+ and (M+K)+ quasimolecular ions in the positive-ion mode. Minor byproducts were observed in some of the samples and the information was used to aid the optimization of the synthetic work.
Russell
W K
WK
Department of Chemistry, Texas A&M University, College Station 77842-3012, USA.
Russell
D H
DH
Busby
M B
MB
Kolberg
A
A
Li
S
S
Maynard
D K
DK
Sanchez-Vindas
S
S
Zhu
W
W
Vigh
G
G
D016477:Artifacts; D003505:Cyclodextrins / Q000138:chemical synthesis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D004987:Ethers / Q000737:chemistry; D017646:Organosilicon Compounds / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013237:Stereoisomerism
D003505:Cyclodextrins; D004987:Ethers; D017646:Organosilicon Compounds; C009660:t-butyldimethylsilyl compounds