6种混剂中代森锰锌的稳定性和ETU的含量

The Stability of Mancozeb in the Six Mixtures and the Level of ETU

采用高效液相色谱和ＧＣ－ＭＳ，研究了在自然条件下贮藏５年的代森锰锌（ＭＺ）制剂的降解。样品用甲醇抽提，测定后经联机检索解析，确定了ＭＺ制剂的主要降解产物和途径。ＭＺ的主要降解产物和途径与一般的ＥＢＤＣｓ相似。ＭＺ的主要降解产物为ＥＴＵ、ＥＤＩ、ＥＵ等，主要降解途径为氧化。按照热贮藏方法（ＣＩＰＡＣＭＴ４６），采用黄原酸盐法测定了ＭＺ制剂单剂的稳定性，对ＭＺ＋ｆｏｓｅｔｈｙｌＡｌ、ＭＺ＋ｃｈｌｏｒｏｔｈａｌｏｎｉｌ、ＭＺ＋ｍｅｔａｌａｘｙｌ、ＭＺ＋ｃａｒｂｅｎｄａｚｉｍ、ＭＺ＋ｔｒｉａｄｉｍｅｆｏｎ和ＭＺ＋ｄｉｍｅｔｈａｃｈｌｏｎ中的ＭＺ稳定性也进行了考察，还对在实验室条件下贮藏２年后的混剂中的ＥＴＵ进行了测定。ＭＺ的热贮相对分解率为９３％～１４３％。贮藏２年的ＭＺ制剂中ＥＴＵ含量为３９６％，５年的为６９３％。ｆｏｓｅｔｈｙｌＡｌ，ｃａｒｂｅｎｄａｚｉｍ和ｔｒｉａｄｉｍｅｆｏｎ可以显著地提高ＭＺ的热贮稳定性。５种混剂贮藏２年后ＥＴＵ含量为１９１％～３１１％（ＭＺ＋ｄｉｍｅｔｈａｃｈｌｏｎ未测定）。

Identification of some degradation products is described by HPLC and capillary gas chromatography mass spectrometry in methanol extract of mancozeb 70 WP after storing 5 years in the laboratory Through analyzing and comparing the obtained mass spectra with the standard mass spectra could identify the degradation products and then determine the proposed degradation pathways The results showed that the degradation products and pathways were very similar to other ethylenebisdithiocarbamate fungicides The degradation products of mancozeb detected in the formulation include ETU, EU(2 imidazolidinone) and EDI(ethylenediisothiocyanat e) Mancozeb is degraded primarily by oxidative reaction The stability of mancozeb and the level of ETU were detected via the xanthated method and HPLC-UV in mancozeb and its mixtures ( mancozeb+ fosethyl Al, mancozeb+chlorothalonil, mancozeb+metalaxyl,mancozeb+carbendazim,mancozeb+triadimefon,mancozeb+dimethachion) by CIPAC MT46 The relative rate of decomposition of mancozeb was 9 3%～14 3% The level of ETU was 3 9% for 2 years,6 9% for 5 years in the formulation Fosethyl Al, carbendazim and triadimefon may enhance stabil ity of mancozeb by heating Except mancozeb+dimethachlon,the levels of ETU in five mixtures were 1 91%～3 11% after storing 2 years Fosethyl Al may significantly reduce formation of ETU in mancozeb formulation