准确确定农药的合理和规范使用对于农业的可持续发展同时保持高质量具有重要意义。杀虫剂噻虫嗪和氰戊菊酯和蔬菜菠菜,卷心菜,卷心菜和生菜在这里被用作研究对象。采用描述性分析和一次反应动力学方程,分析了两种杀虫剂在三种蔬菜中不同施用次数后代谢残留的变化。农药残留水平对δ13C的影响,δ15N,δ2H,采用单因素方差分析和相关分析对蔬菜的δ18O值进行分析。应用偏最小二乘判别分析(PLS-DA)建立了基于稳定同位素的不同农药残留蔬菜的判别模型。结果表明,菠菜中噻虫嗪和氰戊菊酯的首次降解残留,卷心菜,卷心菜生菜符合初级反应动力学方程,但是降解的半衰期很长,和积累发生在第二个应用程序。3种蔬菜对照组中4种稳定同位素比值的差异均有统计学意义,不同农药施用量的三种蔬菜中三分之二的稳定同位素比值存在显著差异。菠菜的δ13C和δ15N值,δ13C,δ15N,和卷心菜的δ2H值,和δ13C,δ15N,δ2H,莴苣的δ18O值与噻虫嗪和/或氰戊菊酯的不同残留物显着相关。对照组的三种蔬菜,菠菜-噻虫嗪-第一,菠菜-噻虫嗪-第二,卷心菜-噻虫嗪-第二,卷心菜-氰戊菊酯-第一,生菜-噻虫嗪-优先,被PLS-DA模型完全识别,而其他含农药残留蔬菜的鉴定模型仍需进一步完善。研究结果为鉴别蔬菜中农药的合理使用提供技术支持,为保证绿色有机蔬菜的真实性提供参考方法。
Accurate identification of the rational and standardized use of pesticides is important for the sustainable development of agriculture while maintaining a high quality. The insecticides thiamethoxam and
fenvalerate and the vegetables spinach, cabbage, and lettuce were used here as study objects. Descriptive analysis and primary reaction kinetic equations were used to analyze the changes in metabolic residues of the two insecticides after different numbers of application in three vegetables. The effects of pesticide residue levels on the δ13C, δ15N, δ2H, and δ18O values of vegetables were analyzed by one-way analysis of variance and correlation analysis. Partial least squares discriminant analysis (PLS-DA) was applied to build discrimination models of the vegetables with different pesticide residues based on stable isotopes. The results showed that the first degradation residues of thiamethoxam and
fenvalerate in spinach, cabbage, and lettuce conformed to primary reaction kinetic equations, but the degradation half-lives were long, and accumulation occurred in the second application. The differences in the four stable isotope ratios in the control group of the three vegetables were statistically significant, and two-thirds of the stable isotope ratios in the three vegetables with different numbers of pesticide applications were significantly different. The δ13C and δ15N values of spinach, the δ13C, δ15N, and δ2H values of cabbage, and the δ13C, δ15N, δ2H, and δ18O values of lettuce were significantly correlated with different residues of thiamethoxam and/or
fenvalerate applications. The control groups of the three vegetables, spinach-thiamethoxam-first, spinach-thiamethoxam-second, cabbage-thiamethoxam-second, cabbage-
fenvalerate-first, and lettuce-thiamethoxam-first, were fully identified by PLS-DA models, while the identification models of other vegetables containing pesticide residues still need to be further improved. The results provide technical support for identifying the rational use of pesticides in vegetables and provide a reference method for guaranteeing the authenticity of green and organic vegetables.