Analysis of cinnamaldehyde and diallyl disulfide as eco-pesticides in soils of different textures-a laboratory-scale mobility study

This work presents for the first time the development of a method for the analysis of cinnamaldehyde and diallyl disulfide in soil by ultrasound assisted extraction followed by gas chromatography-mass spectrometry. The optimized method was applied in a laboratory-scale study of mobility of these substances applied within a bio-pesticide embodiment on three different soil textures, fine sand, sandy loam, and silty clay loam. Two initial soil moistures were approached, 20 and 90 % field capacity, in order to cover different climatic site scenarios (dry-wet locations). After the application, which was carried out as a pulse on the top soil surface, three different sprinkler irrigation regimes (1x, 2x, and 3x field capacity water volume) were simulated. Each experiment was carried out in duplicate. The results have shown that irrigation pushes the compounds down, and their mobility is soil texture dependent, with the sandy loam having the least resistance to leachability. In any case, cinnamaldehyde is shown to be more prone to leach down than diallyl disulfide. Mass balances in each scenario were also discussed. When these bio-pesticides are used for agricultural purposes, the irrigation regime should be adjusted so that the pesticides reach the target location without causing unnecessary environmental contamination.