Intercalibration of chromatographic methods for auxino phytodrugs in Solanaceae

Three chromatographic methods are considered for the determination in Solanaceae of auxino-similar phytodrugs, so called because their structure resembles an auxine plant hormone. The phytodrugs studied were: 2,4-dichlorophenoxyacetic acid, 2,4-dichlorophenoxypropionic acid, 2,4-dichlorophenoxybutyric acid, 2-methyl-4-chlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, naphthylacetic acid and 2-naphthyloxyacetic acid. Three chromatographic methods, respectively based on ion-interaction HPLC, GC–MS with intra-injector derivatisation and GC–MS with pre-injection derivatisation, were developed, optimised and validated. A comparative discussion of the advantages/disadvantages of the methods suggests a strategy for their preferential use, that is essentially a function of the matrix complexity.