Derivatization in Mass Spectrometry—4. Formation of Cyclic Derivatives

Abstract

This fourth in a series of reviews describes a further common derivatization approach, namely, the formation of cyclic derivatives (cyclic acetals and ketals, boronates, siliconides, carbonates and other miscellaneous derivatives) that can be used to increase volatility and to improve chromatographic and, if possible, the mass spectral properties of various di- and polyfunctional compounds. Some chemical aspects of this type of derivatization are briefly discussed. Characteristic mass spectral features of various cyclic derivatives that are helpful in the structure determination, profiling and quantitation of multifunctional organic compounds are presented. Some recent analytical applications of mass spectrometry in conjunction with preliminary cyclic derivative formation are given.

Derivatization by 6‐aminoquinolyl‐N‐hydroxysuccinimidyl carbamate for enhancing the ionization yield of small peptides and glycopeptides in matrix‐assisted laser desorption/ionization and electrospray ionization mass spectrometry

“…Many different methods are available for amino acid derivatization. Reactive groups are the OH group in Ser, Thr and Tyr, the COOH group in Asp and Glu, the NH group in Lys, Arg and at the N‐terminus, and the SH group in Cys; different reactions can be carried out for each of these reactive groups, as comprehensively reviewed by Halket and Zaikin 6–9. Many of these derivatizations are primarily intended to attach a chromophore or fluorophore label.…”

Qualitative confirmation procedure for ephedrines as acetonide derivatives in doping urine samples by gas chromatography/electron ionization mass spectrometry

“…In the course of such derivatization procedures, new five‐, six‐ or even seven‐membered rings with stable configurations can be formed in the molecule under study. As a result, the above‐mentioned polar groups are protected and the derivative possesses increased volatility, good chromatographic properties and sometimes shows mass spectra that can be more efficiently used for structure determination and quantitative determination of the derivatized compounds 23…”

Differentiation of diastereomeric conduramine derivatives under electron ionization and chemical ionization mass spectral conditions

“…Compounds d 3 -3 and d 3 -4 were prepared by the acetylation of 1 and 2 using acetic acid-d 4 ; and d 6 -3 and d 6 -4 were prepared by protecting the corresponding diols with acetone-d 6 in the presence of p-toluenesulfonic acid. 12 All the starting materials were purchased from Sigma-Aldrich (Steinheim, Germany), and the solvents for chromatographic and mass spectral analysis were purchased from Merck (Mumbai, India).…”