超声提取/超高效液相色谱-串联质谱法测定土壤中乙酰甲胺磷与甲胺磷的研究

建立了超声提取/超高效液相色谱-三重四极杆串联质谱(UPLC-MS/MS)快速测定土壤中乙酰甲胺磷和甲胺磷的方法。10. 0 g土壤样品采用20. 0 m L甲醇超声萃取30 min,取上清液过0. 22μm滤膜后进行UPLC-MS/MS分析,外标法定量。结果表明:乙酰甲胺磷和甲胺磷在0. 002～20. 0μg/L质量浓度范围内线性良好(r~2 0. 999),方法检出限分别为0. 004 9μg/kg和0. 003 4μg/kg。在0. 400、4. 00、40. 00μg/kg加标水平下,土壤样品中乙酰甲胺磷和甲胺磷的平均回收率分别为83. 0%～91. 5%和88. 0%～94. 8%,相对标准偏差(RSD,n=6)分别为2. 3%～4. 8%和1. 8%～4. 2%。该方法前处理简单快捷、灵敏度高、定性定量准确,可用于土壤样品中乙酰甲胺磷和甲胺磷含量的快速检测。     

Enantioseparation and dissipation of acephate and its highly toxic metabolite methamidophos in pakchoi by supercritical fluid chromatography tandem mass spectrometry

Acephate is widely used in crops as racemate. However, the enantioselective dissipation of acephate enantiomers has not been investigated in pakchoi. A sensitive and effective approach was established for determining residues of acephate and its highly toxic metabolite methamidophos enantiomers by supercritical fluid chromatography tandem mass spectrometry. Baseline separations for their enantiomers were achieved by using a Chiralcel OD-H column. The optimal chromatographic conditions were obtained as follows: CO₂/ethanol (95/5) as mobile phase; flow rate, 3.0 mL/min; column temperature, 40°C. The mean recoveries (RSDs) of analytes were in the range of 77–83.1% (6.1–9.9%), 75.4–87.5% (9.3–13.2%), and 81.5–84.2% (7.1–13.4%) at three fortification levels (0.005, 0.05, and 0.5 mg/kg for each enantiomer) for interday assay (n = 18). The method was used to evaluate the enantioselective dissipation of acephate and methamidophos in pakchoi. S-acephate dissipated faster than R-acephate, while the concentration of R-methamidophos was higher than that of S-methamidophos during the entire study period. The results indicated that the R-enantiomer of acephate and methamidophos was preferentially enriched in pakchoi. The established analysis approach and the study data provided useful information for the rational use of acephate in agriculture.     

快速气相色谱法测定蔬菜中甲胺磷和水胺硫磷残留量

蔬菜中甲胺磷和水胺磷残余经氯仿萃取后，用气相色谱－火焰光度检测器（ＧＣ－ＦＰＤ）直接测定，色谱柱为ＤＢ－１７大口径石英毛细管柱，采用气相色谱－离子阱质谱系统检测样品中的甲胺磷和水胺硫磷，在三个不同含量水平的收率试验中，本法的回收率为９３．６％－１０４．１％，最低检测限可达０．０６μｇ／ｇ     

γ‐Irradiation Degradation of Methamidophos

The irradiation degradation of methamidophos in aqueous solutions by ⁶⁰Co‐γ rays was investigated. The effects of absorbed doses, saturated gas, and the additive of H₂O₂ on the degradation were also studied. The results showed that the oxidative radical, such as ·OH, played an important role in the irradiation degradation of methamidophos; while the reductive radicals, e^?_aq and ·H, had no contribution to the degradation. The degradation rate of methamidophos increased with the increase of the irradiation dosage. At certain irradiation dosage, methamidophos could be degraded completely. The degradation rate of methamidophos in the solution saturated with oxygen was higher than those saturated with other gases, which reached 100% when the absorbed dose was 8 kGy. H₂O₂ degraded methamidophos slowly when it was used alone, but could accelerate the degradation obviously when it was used with irradiation together.     

Synthesis and Characterization of O,S-Dimethylphosphoramidothioate and N-Acetyl O,S-Dimethylphosphoramidothioate

O,S-Dimethylphosphoramidothioate (methamidophos) and N-acetyl O,S-dimethylphos- phoramidothioate (acephate) were synthesized by new methods to investigate the structure–activity study of acetyl cholinesterase (AChE) inhibition through the parameters of logP, δ ³¹P, and IC₅₀. After their characterization by NMR (³¹P, ³¹P{ ¹H}, ¹³C, and ¹H), IR, and mass spectroscopy, logP and δ ³¹P (³¹P chemical shift in NMR) were used to evaluate lipophilicity and electronical properties. The logP values for methamidophos and acephate were experimentally determined by the GC-shake-flask method, and the ability of the compounds to inhibit human AChE was evaluated by a modified Ellman's assay.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

超声波诱导降解水溶液中甲胺磷

超声波降解;废水处理;超声波诱导降解水溶液中甲胺磷