阿维菌素3种剂型的光解研究

以太阳光为光源,利用玻片药膜法和高效液相色谱法研究浓度、水质硬度、pH和共存离子等因子对阿维菌素乳油、水乳剂和微乳剂3种液体剂型光解的影响。结果表明：3种阿维菌素液体剂型光解率随光照时间延长而逐渐增大。在试验初始浓度范围内,3种阿维菌素制剂光解均符合一级动力学方程,且与药液浓度呈负相关。在不同浓度、pH、共存离子条件下,阿维菌素的光解速率均表现为乳油〉水乳剂〉微乳剂,pH对单一剂型光解有较大影响,而共存离子对其影响作用较小。在不同浓度硬水条件下则表现为随水质硬度增加,微乳剂半衰期减少,水乳剂和乳油略微增大,在蒸馏水下的半衰期为微乳剂〉水乳剂〉乳油,而在684mg·L-1硬水时半衰期为水乳剂〉微乳剂≈乳油。相比于乳油,微乳剂和水乳剂光解速率较慢,可以有效延长阿维菌素持效期,进一步提高阿维菌素在田间的应用效果。

Photodegradation of Three Abamectin Liquid Formulations

Photodegradation of abamectin B 1a EC,EW and ME on thin films under solar irradiation system with different concentrations,water hardness,pH and coexistent ions was studied by using HPLC.The results showed that：Photodegradation of the three abamectin liquid formulations increased with solar irradiation time.In the experimental range of initial concentration,the photodegradation of abamectin followed the first order reaction kinetic and was negatively correlated with the initial concentration.The photodegradation rate was emulsifiable concentrate（EC）emulsion in wate（rEW）microemulsion（ME）in different concentration,pH or coexistent ions.In the test concentration 800 mg· L-1 of abamectin,the half-time period of liquid formulations：ME was 6.29 h,EW was 4.39 h,and EC was 3.28 h.There was a great influence on photodegradation of pH but almost no influence of coexistent ions.There was a different effect of the concentration of Ca 2＋ and Mg 2＋ in water that with the concentration of Ca 2＋ and Mg 2＋ increased,the half-time period of ME was decreased while the half-time period of EC and EW was slightly increased,which the half-time period of ME：distilled water was 5.33 h,hardness water of 342 mg·L-1 was 3.23 h,and hardness water of 684 mg·L-1 was 2.74 h.The half-life was MEEWEC in distilled water while EWME≈EC in 684 mg·L-1 of hardness water.It was visible that the photodegradation rate of ME and EW was slower than that of EC,and using ME and EW could prolong the validity of abamectin and could promote the application of abamectin in field.