分子吸收光度法测定万寿菊中代森锰锌残留量

目的: 采用分子吸收光度法测定万寿菊中代森锰锌残留。 方法: 通过蒸馏和溶液吸收实验装置,氯化亚锡催化,二乙基二硫代氨基甲酸钠分解定量产生二硫化碳气体,通过浓硫酸脱氧脱水,氢氧化钾的甲醇液吸收,用分光光度法在304 nm波长处测定其标准曲线。代森锰锌以平均相对分子质量333计,可通过平均相对分子质量计算出代谢锰锌的含量。 结果: 万寿菊中添加浓度为10 mg·kg^-1和20 mg·kg^-1(以二硫化碳计)的回收率(n=5)分别为95.9%和93.2%,RSD分别为4.8%和3.7%;最低检测限为2 mg·kg^-1。 结论: 该方法操作简单,灵敏度高,适合大批量样品的检测。

Objective: To establish a convenient and fast method for determination of mancozeb residue level in marigold (Tagetes erecta L.). Methods: The method included distillation and absorption parts. Sodium diethyldithiocarbamate in SnCl₂ catalyst was decomposed and released gas carbon disulfur quantitatively,passed through sulphuric acid solution,was absorbed by KOH/CH₃OH solutions,then standard curve was determined by spectrometry with 304 nm wavelength. The meaning relative molecular mass of mancozeb was 333,so mancozeb content was calculated by the meaning relative molecular mass. Results: The recoveries(n=5) of mancozeb in marigold were 95.9%,93.2% at added concentrations of 10 and 20 mg·kg^-1(carbon disulfide),with their RSDs of 4.8% and 3.7%,respectively. The detection limits were 2 mg·kg^-1. Conclusion: The method is more selective and sensitive and suited for large samples analysis.