Evaluation of Factors Influencing Recovery of Herbicide

Many modern analytical methods deal with the trace-level determination of compounds of interest in highly complex environmental samples by means of chromatographic techniques. The introduction of a "clean" sample into an analytical instrument can make analyses easier and prolongs the equipment life. The use of solid-phase extraction (SPE) has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquid-liquid extraction (LLE). The application of SPE can give selectivity of extraction providing a purified and concentrated extract. Through this study, optimization of trace enrichment and sample clean-up method via the use of bonded silica cartridges is discussed. SPE using bonded silica has been optimized with respect of sample pH, sample concentration, elution solvent strength, sample volume, and elution volume. In this investigation a variety of non-polar sorbent cartridges were also screened. During this study, the octadecyl bonded silical cartridge (C18) has proven successful in simplifying sample preparation. The present approach proved that MCPA could be retained on C18 based on specific interaction. Further study employed methanol to extract the analyte from spiked water and gave a clean sample for high pressure liquid chromatography equipped with ultra violet detection system. The optimized method was validated with three different pools of spiked samples and showed good reproducibility over six consecutive days as well as six within-day experiments.