High-Temperature Liquid Chromatography of Isomeric Organochlorine Herbicides and Their Degradation Products

Alachlor, acetochlor, and metolachlor are organochlorine herbicides extensively used for weed control in agricultural practices, yet their use is prohibited within the European Union due to environmental and health concerns. These compounds and their degradation products exhibit high environmental persistence, necessitating reliable and rapid analytical methods for monitoring. Conventional reversed-phase liquid chromatography employing C18 columns is commonly utilized for their analysis. However, alkyl silica columns, and especially C18 columns, are not suitable for the effective separation of isomers, necessitating the integration of tandem mass spectrometry for enhanced analytical accuracy. This study explores the application of a porous graphitic carbon-based column to overcome these limitations. High-temperature chromatography enabled improved efficiency and selectivity in separating the target compounds. The influence of temperature, flow rate, pH, and mobile phase composition on the retention of alachlor, acetochlor, metolachlor, and their degradation products was systematically evaluated. A method suitable for separation and quantification of the herbicides was developed, highlighting the potential of porous graphitic carbon columns for robust and precise analysis in complex environmental matrices.