Alkyl Chloroformates in Sample Derivatization Strategies for GC Analysis. Review on a Decade Use of the Reagents as Esterifying Agents

The neccessity to derivatize polar analytes prior to separation often disqualifies gas chromatography (GC) as a method of choice in the field of biomedical/pharmaceutical analysis. Laborious and lengthy protocols for treating compounds prior to the analysis were discouraging. Only few derivatization approaches were well-established over decades, primarily silylations. To its assets belongs universality and efficacy, to shortcomings necessity for dry residue and prolonged reaction time, often under heating. Similarly, the next field-proven esterification-acylation two-step procedures suffered from the same pre-requisites. Current investigations in the field of derivatization turned attention to chemical reactions proceeding in aqueous environment and obviating multiple reaction steps and heating. Application of alkyl chloroformates (RCF), under conditions discovered more than a decade ago, met such criteria. Instantaneous conversion of hydrophilic compounds to organophilic ones became often an integral part of sample preparation procedures with negligible time and costs required. This review attempts to bring forward some of the most important studies on RCF-mediated derivatizations in the last decade and to figure out general utility of the approach in analyzing polar organic compounds by GC, with particular attention to polyfunctional organic acids, especially amino acids (AAs).