Multidimensional chromatography: A powerful technique in analysis of chiral agrochemicals in environment

Abstract

Multidimensional chromatography (MDC), including gas (MDGC) and liquid (MDLC) chromatography, has emerged as an excellent option for analyzing complex samples where one-dimensional chromatography does not provide sufficient peak capacity in reasonable analysis times. Agrochemicals in environment and in food, typically at trace levels, constitute extremely complex samples. Chiral agrochemicals, usually present with numerous other chiral and achiral molecules in environmental samples, represent a second great analytical challenge: the increment in the information dimensionality provided by a single chiral column can only be achieved by adding a second separative step, if classical detection methods will be used. Chiral agrochemicals, often marketed and applied as racemates. Once released into the environment, enantiomers and their (chiral) metabolites generally exhibit enantioselective behavior in degradation, bioaccumulation, and toxicity. Enantioselectivity is rarely addressed in pesticide regulations, even though quantitative determinations of enantiomeric forms are essential for proper risk management. This chapter focuses on the key features of multidimensional chromatography, the most common instrumental configurations for both MDGC and MDLC, with special attention to the specific requirements that these techniques must fulfill when applied to the enantioresolution of chiral agrochemicals.