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971.
目的 建立分散固相萃取结合液相色谱-串联质谱同时测定油料油脂中 67 种除草剂残留的检测方法。方法 选取花生、大豆、油菜籽、花生油、大豆油及菜籽油为典型基质试样,经 1% 甲酸-乙腈提取,通过乙二胺基-N-丙基和无水 MgSO4分散固相萃取净化。以甲醇和 5 mmol/L 乙酸铵(含 0. 1% 甲酸)为流动相梯度洗脱,采用 C18色谱柱分离,ESI 离子源正负离子模式同时进行多反应监测(MRM),基质标准曲线外标法定量。结果 基质加标试验结果表明,0. 000 5~0. 08 mg/L 浓度范围内 67 种除草剂线性良好,决定系数(R2)均>0. 992,定量限(LOD)为 0. 005~0. 02 mg/kg。3 个加标水平下(LOD、2LOD、10LOD)的回收率为 62. 3%~118. 1%,RSD(n=6)均<15%。结论 本方法稳定性高、特异性强、灵敏、准确、高效,可以用于油料油脂中多种除草剂残留的定性定量检测。 相似文献
972.
973.
B族维生素对沼泽红假单胞菌产氢以及降解废水的影响 总被引:1,自引:0,他引:1
研究了B族维生素对沼泽红假单胞菌生长和产氢的影响以及其对模拟废水的处理效果。考察了在基础培养基中加入不同配比B族维生素时的产氢状况和废水处理效果。结果表明,B族维生素对沼泽红假单胞菌的生长,产氢以及处理废水能力都是有影响的。从产氢量的角度来看,空白对照组(未添加任何B族系列维生素)的产氢量最少,产氢量累积达到57.88 mL/L,加入全部维生素累积量128.83 mL/L,缺少VB2的产氢累积为83.25 mL/L,低于加入全部维生素累积量,因此VB2对产氢有促进作用,而缺少VB4的产氢量累积高达337.43 mL/L,高于加入全部维生素累积量,因此VB4对产氢有抑制作用。而对于废水处理效果来看,只加入复合VB的COD去除率达到最高值64.706%。 相似文献
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975.
976.
977.
Valentina Nania Guido Enrico Pellegrini Laura Fabrizi Giulio Sesta Patrizia De Sanctis Dario Lucchetti Mauro Di Pasquale Ettore Coni 《Food chemistry》2009
Perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS) are environmental contaminants belonging to a chemical group known as perfluorinated compounds (PCFs). The United States Environmental Protection Agency (US EPA) considers both compounds to be carcinogenic. The goal of the present study was to evaluate the contamination levels of PFOS and PFOA in edible fish of the Mediterranean Sea. Twenty six fish muscles, 17 fish livers, five series of cephalopods (each composed of ten specimens) and thirteen series of bivalves (each composed of about 50 specimens) were used for the investigation. A fast sample treatment, followed by an LC–ESI–MS/MS method is described for the identification, and quantification of PFOA and PFOS in fish. The method was in-house-validated through the determination of precision, accuracy, specificity, calibration curve, decision limit (CCα), and detection capability (CCβ). The results showed PFOA and PFOS levels in fishes and molluscs lower than those reported for analogue matrices in different geographic areas. Therefore, our biomonitoring results did not show that the Mediterranean Sea had any particularly alarming pollution by PFCs, although it is located in a semi-closed basin with scarce water change. Nonetheless, a worrying element is that a few fish showed extremely high contamination by PFOA and PFOS. This finding needs further clarification in order to assess whether such unusual contamination is linked to “dot-like” pollutant release, which could explain the anomaly. 相似文献
978.
Qinglei Liu Di Zhang Tongxiang Fan Jiajun Gu Yoshinari Miyamoto Zhixin Chen 《Carbon》2008,46(3):461-465
Carbon-matrix composites with self-assembly interconnected carbon nano-ribbon networks were fabricated using natural and inexpensive rice husks by impregnating the rice husks with transitional metal solutions and sintering. The nano-structure of the composite was characterized using transmission electron microscopy. The electromagnetic interference shielding effectiveness of the composite was evaluated in the frequency range of 30 kHz–1.5 GHz. The electrical conductivity was measured as a function of the sintering temperature. These characteristics were compared with those of carbon-matrix composites without nano-ribbon networks. 相似文献
979.
980.
The photoelectrochemical polymerization of poly(3,4-ethylenedioxythiophene), PEDOT, was successfully realized on anodic film grown to 50 V on magnetron sputtered niobium. Photocurrent Spectroscopy was employed to study the optical properties of Nb/Nb2O5/PEDOT/electrolyte interface in a large range of potential, and to get an estimate of the band gap and flat band potential of both the oxide and the polymer. Scanning Electron Microscopy was used to study the morphology of PEDOT. Both the optical and morphological features of the photoelectrochemically grown polymer were compared with those showed by PEDOT electropolymerized on gold conducting substrate. 相似文献