三唑磷原药及其中相关杂质治螟磷的水解特性研究

Hydrolysis Behaviour of Technical Triazophos and its Relevant Impurity Sulfotep

采用气-质联用定性、气相色谱法定量,对三唑磷原药中的三唑磷及其相关杂质治螟磷在不同温度和不同pH值下的水解规律进行了研究。结果表明：三唑磷属于水解不稳定化合物,在50℃时5d的水解率在pH为5、7、9时分别为48.0%、70.7%和79.4%;杂质治螟磷则均大于86%,较三唑磷更易水解。三唑磷和治螟磷的水解速率受温度影响较大,温度升高,半衰期缩短;pH值增大,三唑磷水解速率明显加快,而pH值对治螟磷水解的影响不明显。相同条件下,三唑磷的水解速度比治螟磷慢,其水解半衰期是治螟磷的1.4-6.0倍,差异随温度升高和pH值变大而减小。在上述实验条件下,三唑磷的水解特性介于易降解到中等降解之间,治螟磷呈易降解特性。

Hydrolytic rates for technical triazophos and its relevant impurity sulfotep at different pH and temperature were determined qualitatively by gas chromatography-mass spectrometry（GC-MS）,and quantified by gas chromatography.The results showed that triazophos belonged to hydrolytically unstable substance.The hydrolysis rates for triazophos at 50℃ after 5 days under pH 5,7,9 were 48.0%,70.7% and 79.4%,respectively.The hydrolysis rates for sulfotep at 50℃ after 5 days under pH 5,7,9 were over 86%.Sulfotep was subject to be hydrolyzed faster than triazophos.Hydrolysis rates for triazophos and sulfotep were significantly affected by temperature.The half-life decrease with temperature.Hydrolysis rates for triazophos increased rapidly with the medium at high pH conditions,while no significant change of hydrolysis rates of sulfotep was observed at alkaline solutions.The hydrolysis rates of triazophos were 1.6～6.0 times slower than that of sulfotep under the same condition.No such difference was observed when pH and temperature was increased.Under the experimental conditions mentioned above,triazophos belongs to the pesticide with a readily to moderately hydrolyzed character,and sulfotep belongs to the pesticide type which could readily be hydrolyzed.