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1.
Theoretical investigation on the gas‐phase degradation reaction mechanism of methamidophos (MAP) and chloramine phosphorus (CHP) with OH radicals is performed. The equilibrium geometries and the harmonic vibration frequencies of the stationary points are obtained at M06‐2x/6‐31+G(d,p) level, and the higher‐level energetic information is further refined at M06‐2x/6–311++G(3df,2p) level. The rate constants for the 14 reaction channels are calculated by the improved canonical variational transition state theory with small‐curvature tunneling correction over the temperature range 200–2000 K. The three‐parameter expressions of k1(T) = 1.53 × 10?19T2.74exp(?1005.12/T), k2(T) = 1.36 × 10?20T3.02exp(?1259.56/T) are given. The total rate constants of all reaction channels of MAP with OH radicals are in good agreement with the available experimental data. Our results indicate that the H‐abstraction reactions on methyl are the major channels for the reaction of MAP and CHP with OH radicals. © 2015 Wiley Periodicals, Inc.  相似文献   
2.
建立了乙酰甲胺磷、甲胺磷对映体在茶叶基质中的手性拆分与定量方法。比较了2种手性柱对乙酰甲胺磷及甲胺磷对映体的分离效果,并对分离效果较优的BGB-176手性柱进行色谱条件优化。茶叶样品经改良QuEChERS法处理后,气相色谱测定,外标法定量。在0.04,0.08,0.4 mg/kg 3个加标水平下,甲胺磷、乙酰甲胺磷的回收率分别为58.3%~66.4%和50.8%~57.6%,相对标准偏差(n=5)均小于7%。方法检出限为0.003~0.01 mg/kg。该方法简便、可靠,满足分析要求。通过实际样品的检测,发现乙酰甲胺磷、甲胺磷对映体在茶树上存在一定的降解差异。  相似文献   
3.
Behaviour of acephate and its metabolite methamidophos in apple samples   总被引:3,自引:0,他引:3  
Summary A study of the decay of acephate in apple samples was carried out, including penetration studies and the transformation of acephate in to its main metabolite, methamidophos. Sample treatment involved extraction with ethyl acetate and determination by gas chromatography with nitrogen—phosphorus detection (GC-NPD). Three different parts of the fruit were studied separately: apple surface, peel and pulp. Recoveries were measured at three spiked levels, ranging from 0.050 to 0.504 μg g−1 for acephate and 0.049 to 0.492 μg g−1 for methamidophos. Mean acephate recoveries were 93.0 to 115.5% from peel and 99.2 to 110.2% from pulp, while methamidophos recoveries were 77.2 to 104.2% and 77.5 to 98.6% from peel and pulp, respectively (n=6). Results showed that acephate penetrates into the fruit, where it is transformed to methamidophos. This transformation was not seen on the external apple surface.  相似文献   
4.
微生物酶催化甲胺磷降解机理初探   总被引:8,自引:0,他引:8  
甲胺磷 (MAP)农药经微生物酶 -甲胺脱氢酶催化后 ,采用聚酰胺薄膜层析、钼酸铵试剂和 HPL C等分法 ,分别可检测出氨基、磷酸根和甲醇等化合物 .将去除氨基的 MAP溶液作小鼠灌胃试验 ,发现该农药的毒性明显降低 .文中还对 MAP在自然界的降解过程等问题进行了讨论 .  相似文献   
5.
The occurrence of pesticides in vegetables such as tomato poses an increasing attention to their potential risk to human health. In this study, acephate and its metabolite methamidophos were investigated for their transport and degradation in tomato cultivated in spiking nutrient solutions containing acephate at 1 mg/L. Acephate was taken up and transported via xylems with the concentrations of 41–145 μg/L in xylem sap at 2 and 8 cm above the roots in control treatment. The residue levels of methamidophos derived from acephate were in a range of 0–4.21 μg/L, being 0.00–3.73% of the parent acephate. The influence of three plant growth regulating substances, 1-naphthylacetic acid (NAA), glucose and phlorizin, on the transport and degradation of acephate and methamidophos in tomato was evaluated. All of these substances had positive effects on the transport of acephate and methamidophos in tomato xylem system. The NAA or glucose treatment promoted the degradation of acephate to methamidophos; however, with the addition of phlorizin, the concentrations of acephate were reduced in comparison to that under glucose treatment, suggesting that phlorizin would cause an inhibitory effect on the transport of acephate in tomato plant. These results may indicate an effective approach to reduce acephate and methamidophos residues in tomato.  相似文献   
6.
以正相硅胶/选择洗脱为核心,建立了一种适用于各种复杂基质食品中甲胺磷残留分析的前处理方法.样品用无水Na2SO4配合乙酸乙酯均质研磨,超声波辅助提取,提取液经PSA粉末分散固相萃取和LC-Si柱单一溶剂选择洗脱净化后,供气相色谱仪(GC)和超高效液相色谱-串联质谱仪(UPLC-MS/MS)分析.气相色谱采用火焰光度检测器(FPD),液相色谱-质谱联用采用电喷雾正离子方式(ESI+),T3键合技术(HSS T3)和亲水作用(HILIC)超高效液相色谱柱分离,外标法定量.方法简便、快速,通过优化前处理和上机条件,在最优条件下进行测试,气相色谱法、液相色谱-质谱联用法的定量下限(S/N≥10)为0.0007~0.006 mg/kg,回收率分别为73%~90%, 81%~96%,相对标准偏差分别为2.4%~6.1%, 5.2%~10.8%.并对选择洗脱净化过程中的作用机理进行了研究.  相似文献   
7.
果蔬类农产品中农药残留量检测的不确定度评定   总被引:2,自引:1,他引:1  
对NY/T 761-2004法测定果蔬类农产品中农药残留量的不确定度进行评定。通过建立数学模型,分析了测量过程的不确定度主要来源于提取溶剂量取体积不确定度、分取液体积不确定度、定容体积不确定度、标准溶液不确定度、峰面积不确定度。以甲胺磷的测量为例,对不确定度的各个分量进行计算,当甲胺磷检测浓度为1.091μg/g时,扩展不确定度为0.036μg/g。  相似文献   
8.
建立了加速溶剂萃取/超高压液相色谱-质谱联用测定土壤中甲胺磷的方法。确定最佳萃取条件为:萃取溶剂为乙腈,萃取温度80℃,静态萃取时间10 min,循环2次。萃取液经旋转蒸发仪浓缩后,进超高压液相色谱-质谱分析,外标法定量,质谱定性。结果表明,甲胺磷的线性范围为3.15~1 050μg/L,相关系数为0.999 1。低、中、高3个加标水平下甲胺磷的平均回收率为72%~82%,相对标准偏差为5.8%~8.6%,检出限为0.05μg/kg。该方法具有良好的分离效果、较宽的线性范围和较高的灵敏度,可用于实际样品检测。  相似文献   
9.
碳纳米管改性TiO2的光催化性能   总被引:9,自引:0,他引:9  
本文研究碳纳米管改性TiO2光催化剂的制备和影响其光催化性能的因素。实验结果表明,CNT的加入方法,CNT的含量,催化剂的灼烧温度等均影响光催化剂的光催化性能。制备的CNT-TiO2光降解低浓度的甲胺脾农药(40.7lmg/L)具有很好的效果,光催化降解过程符合一级反应动力学方程。  相似文献   
10.
 建立了同时测定茶叶中噻嗪酮、甲胺磷、乙酰甲胺磷和三唑磷4种农药残留量的测定方法。在45 ℃加温条件下,用乙酸乙酯-正己烷混合溶剂提取及活性炭色谱柱净化,用不同配比的乙酸乙酯-正己烷混合液梯度洗脱待测组分,以DB-210毛细管色谱柱分离、氮磷检测器测定。结果表明,上述4种农药在10 min内能很好地分离;样品加标回收率(n=3)为73.4%~96.9%。方法的变异系数为2.49%~3.35%,茶叶(干重)中4种农药的定量检测下限为7.0~12.0 μg/kg。  相似文献   
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