On-line coupled extraction and separation using superheated water for the analysis of triazine herbicides in spiked compost samples

An on-line method, with a purely aqueous mobile phase, has employed linked superheated water extraction and superheated water separation for the analysis of triazine herbicides in spiked compost samples. After the superheated water extraction, a X-Terra solid-phase trap was used to collect and focus the extracted analytes. The trapped analytes were then released by thermal desorption and passed directly to a superheated water chromatographic separation using a PGC column. Two clean-up steps (prior to extraction and separation) were included to remove most of the interfering matrix components. The effects of the sample matrix and the extraction temperatures on the recovery of the triazines were investigated. Despite some thermal degradation of the chloro-triazines during the SWE, the on-line SWE-SWC method was sensitive and rapid. The coupled method could potentially reduce costs and labour and by using only water in every stage is compatible with the concepts of green chemistry.