Effects of parameters on microwave assisted extraction of triazines from soil: evaluation of an optimisation trajectory

The effects of relevant parameters on microwave assisted solvent extraction (MASE) of triazines in soil samples were studied by a large number (> 200) of experiments. The experiments have been applied to different types of soil samples which were spiked with five triazines with different polarities. The experiments were partly selected on the basis of experimental designs and partly selected ad hoc to study unexpected phenomena or parameters which were not incorporated in the designs. This paper shows that a systematic interpretation of all experimental results from a trajectory of optimisation experiments is possible using models for both extraction efficiency and for the GC-NPD analysis. In such a trajectory some experiments will have larger standard deviations. This is handled by using a variance model in combination with the maximum likelihood method.