Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

Abstract

The review is devoted to alkylation (arylation) as a widely employed derivatization procedure for the protection of OH (carboxylic acids, phosphoric acids, sulfonic acids, alcohols, polyols, phenols, enols), SH (thiols) and NH (amines, amides) groups in order to increase volatility, to improve the chromatographic properties and, if possible, mass spectral properties of derivatives. Chemical aspects of derivatization and various alkylation (arylation) reagents and reaction procedures are described. Specific mass spectral (electron ionization, chemical ionization) features of derivatives helpful in identification, structure elucidation, profiling and quantitative determination of the above-mentioned polar compounds by coupled gas chromatography or high-performance liquid chromatography are discussed. Some common analytical applications of the procedures in organic chemistry, clinical chemistry, environmental chemistry etc. are briefly summarized.

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.…”

Chemometric Strategies for the Extraction and Analysis Optimization of Herbicide Residues in Soil Samples

“…For some weak acids deprotonation and thermally decomposition of the resulting salts after derivatization have been reported to occur simultaneously in a heated GC injector , meanwhile other authors recommend pre-heating in an oven in a closed sample vial previously to injection (Halket & Zaikin, 2004). In order to evaluate the usefulness of pre-heating, standard mixtures were incubated for 5-30-45 min at three different temperatures: 40 ºC (recommended maximum heating temperature recommended in the TMSH label), 70 ºC, both maintained in an oven, and 20 ºC, kept constant in an incubation chamber to simulate the absence of pre-heating.…”

Thermally assisted methylation and subsequent silylation of scheduled acids of chemical weapon convention for on-site analysis and its comparison with the other methods of methylation

“…In addition, only a very limited range of equipment is approved for on-site analysis by the OPCW inspectors. The phosphonic acids are amenable to GC-MS only after derivatisation and have been reviewed in the recent articles [14][15][16][17][18]. The most important and common derivatisation methods are silylation, methylation and pentafluorobenzylation [19][20][21].…”