^(60)Coγ射线辐照降解吡虫啉稀水溶液

^(60)Co γ-ray irradiation degradation of dilute aqueous solution of imidacloprid

采用^(60)Coγ射线辐照降解吡虫啉稀水溶液,并对辐照前后的水样进行高效液相色谱(HPLC)、离子色谱(IC)和高效液相色谱-质谱联用(HPLC-MS)等检测。实验结果表明,吡虫啉的降解率随吸收剂量的增大而不断增大,当吸收剂量为1.56 kGy时,降解率达到100%;吡虫啉的辐照降解产物包括Cl^-、NO_2^-、NO_3^-和NH_4^+四种无机产物,2-chloro-5-imidazol-1-ylmethyl-pyridine、1-(6-chloro-pyridin-3-ylmethyl)-1,3-dihydroimidazol-2-ylideneamine、单羟基化吡虫啉和双羟基化吡虫啉4种有机产物。强氧化性的·OH容易进攻吡虫啉分子中的C=N键、N-N键、C-Cl键以及亚甲基中的C-H键。

Degradation of imidacloprid in dilute aqueous solution irradiated by ^60Coγ-ray was studied. The samples before and after irradiation were detected by high performance liquid chromatography （HPLC）, ion chromatography （IC） and high performance liquid chromatography-mass spectrometry （HPLC-MS）. The experimental results show that the degradation rate increases gradually with the absorbed dose and reach 100% at the absorbed dose of 1.56 kGy. Imidacloprid irradiation degradation products include four kinds of inorganic ions of Cl^-, NO2, NO3, and NH4^＋ and four kinds of organic products of 2-chloro-5-imidazol-1-ylmethyl-pyridine, 1-（6-chloro-pyridin-3 -ylmethyl）- 1,3 -dihydro-imidazol-2-ylideneamine, mono-hydroxylated imidacloprid and double-hydroxylated imidacloprid. Oxidative free radicals .OH could attack C-Cl bond, N-N bond, C=N bond and C-H bond of imidacloprid molecule easily.