Chemical derivatization in bioanalysis.

Abstract

Applications Chemical derivatization has long proved itself as an analytical technique in bioanalysis to overcome problems associated with low ionization efficiency, compound instability, poor selectivity or unacceptable chromatographic performance (poor retention, bad peak shape and carryover issues) and even poor volatility for GC separation [1,2]. This technique is a powerful tool in many areas of chemistry including medical, forensic, food science, doping control and environmental disciplines. The goal of chemical derivatization is to modify the structure of the analyte (either a nucleophile or electrophile) using a chemical reagent (either an electrophile or nucleophile depending on the nature of the analyte) and, as a result, a new compound (the reaction’s derivate) with improved chemical and physical properties for analysis is formed. The reaction conditions (amount of the reagent, reaction time and temperature, etc) are optimized in favor of the formation of the desired derivative with the highest possible reaction yield. Additional sample clean up procedures can be developed to eliminate unwanted byproducts and excess reagents, thereby minimizing analyte inferences upon analysis. Using chemical derivatization, analysis of the impossible becomes possible. Many examples of this have been presented in the literature; impacting GC, LC–MS/MS [1–3] and NMR [4–6] detection. Most notable has been the chromatographic separation of enantiomers through chiral derivatization using specific resolving reagents without the use of specialized chiral columns and separation conditions [7–9].