Determination of 1-methylcyclopropene residues in vegetables and fruits based on iodine derivatives.

An innovative method was established for the determination of 1-methylcyclopropene (1-MCP) in vegetables and fruits. Due to its small molecular weight and low boiling point, it was difficult to obtain quantitative analysis for 1-MCP, especially at the residual level. In this work, based on its iodine derivatives, 1-MCP was derived to 1,2-diiodo-1-methylcyclopropane, which was much easier for trace and accurate chromatographic analysis. During the method validation, the method validation results were satisfactory in terms of linearity (4 ~ 400 µg/L, and R ≥ 0.959), matrix effect (-89% ~ -13%), accuracy (80 ~ 100%), sensitivity (limits of quantification, 5 μg/kg) and precision (relative standard deviations ≤ 19%), which was in accordance with the Chinese guidelines for the testing of pesticide residues in crops. Finally, the proposed analytical method was used to monitor the 1-MCP residue levels in commercially available samples, and all the values were below 5 µg/kg, which satisfied the EU or Japan MRLs of 1-MCP.