Dimethomorph (98.7%) standard was purchased from Dr. Ehrenstorfer GmbH (Augsburg, Germany). A water-dispersible granule (WG) containing 50% Dimethomorph was obtained from Zhonggang Wanxiang Agricultural Co., Ltd. (Zhengzhou, China). Formic acid of chromatographic purity was acquired from Fluka (Newport News, VA, USA). Acetonitrile and methanol of HPLC grade were supplied by Thermo Fisher Co., Ltd. (Waltham, MA, USA) Analytical-grade sodium chloride and activated anhydrous sodium sulfate were obtained from Sigma-Aldrich (Steinheim, Germany). The graphitized carbon black adsorbent (GCB, 120–400 mesh) was sourced from ANPEL Laboratory Technologies Inc. (Shanghai, China).
Acetonitrile was used to make standard pesticide stock solutions with a concentration of 1000 mg L−1, which were then kept at −20 °C. Acetonitrile was used to dilute the stock solution to generate the standard working solutions required for fortification and calibration, which were made fresh as needed. The solvent calibration and matrix-matched solutions were made by diluting the stock solutions with Acetonitrile and blank extracts from all matrices, respectively. Before use, all standard solutions were kept at 4 °C.
Acetonitrile was used to make standard pesticide stock solutions with a concentration of 1000 mg L−1, which were then kept at −20 °C. Acetonitrile was used to dilute the stock solution to generate the standard working solutions required for fortification and calibration, which were made fresh as needed. The solvent calibration and matrix-matched solutions were made by diluting the stock solutions with Acetonitrile and blank extracts from all matrices, respectively. Before use, all standard solutions were kept at 4 °C.