The effects of spraying and root irrigation on the uptake and transport of the fungicide difenoconazole under hydroponic and soil cultivation were investigated. Rice was used as the crop for a short-term exposure experiment. A modified QuEChERS pre-treatment combined with ultra-high-performance liquid chromatography-tandem mass spectrometry was used to extract and detect difenoconazole from rice plants, water and soil. The recoveries of difenoconazole were in the range of 72.8-110.5%, with a relative standard deviation of 2.4-19.5% for all the samples when spiked with 0.01, 0.1 and 1 mg kg-1 of difenoconazole, respectively. The limit of quantitation (LOQ) of this method was 0.01 mg kg-1. The exposure results showed that difenoconazole could be absorbed by rice plants and transmitted to different parts of rice plants in all the treatments. In the hydroponic experiment, difenoconazole was mainly distributed in the roots of rice regardless of whether irrigation or spraying was used. For rice cultivated in soil, difenoconazole mainly accumulated in leaves after the root irrigation treatment, whereas after the spraying treatment, the rice roots were the main site of accumulation of difenoconazole. This experiment extends our knowledge of the influence of the cultivation system and application mode on the translocation of difenoconazole in rice plants.
Keywords: Culture patterns; Difenoconazole; Distribution; QuEChERS; Rice; UHPLC-MS/MS.