鱼肉样品以Florisil硅藻土层析柱净化后,经气相色谱-电子轰击离子源-质谱法(GC-EI-MS)分析其中8种邻苯二甲酸酯(PAEs)含量:邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丙酯(DPrP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二...鱼肉样品以Florisil硅藻土层析柱净化后,经气相色谱-电子轰击离子源-质谱法(GC-EI-MS)分析其中8种邻苯二甲酸酯(PAEs)含量:邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丙酯(DPrP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二戊酯(DPeP)、邻苯二甲酸二环己基酯(DCHP)、邻苯二甲酸二己酯(DHP)、邻苯二甲酸二(2-乙基己基)酯(DEHP).比较了外标和内标法定量,并确定苯甲酸苄基酯为内标物;优化了提取剂、吸附剂和洗脱剂的种类,以及洗脱体积等样品前处理方法;尤其对分析空白的控制问题进行了详细讨论;准确分析了5种鱼样品中此类物质含量.该方法的线性范围为50.0～800μg·L-1,相关系数(R)大于0.99986,相对标准偏差(Relative standard deviation,RSD)均小于12.7%,检测限(Limit of detection,LOD)低于3.66μg·L-1,样品的加标回收率为74.0%～113%.其线性范围、相关系数、准确度、精密度和LOD等指标均满足鱼肉中多种PAEs同时分析的要求.展开更多
The corrosion behavior of water borne epoxy-ester primer coatings (10% - 50% PVCs) was evaluated through electrochemical techniques such as polarization and impedance spectroscopic (EIS) measurements. Studies were car...The corrosion behavior of water borne epoxy-ester primer coatings (10% - 50% PVCs) was evaluated through electrochemical techniques such as polarization and impedance spectroscopic (EIS) measurements. Studies were carried out for a longer duration of exposure extending up to 60 days in aqueous solution of NaCl (5%). Corrosion current (icorr), Corrosion potential (Ecorr), Coating resistance (Rc), Charge transfer resistance (Rct), Coating capacitance (Cc), Double layer capacitance (Cdl), break point frequency (fb), Water uptake (∮), diffusion coefficient (Dw) etc., indicated that 10% - 30% PVC coatings performed well in comparison to higher PVCs. Changes in the electrochemical characteristics were found to occur as a function of exposure time in all cases. The corrosion stability of the coatings were found to be greatly affected by the percentage of PVCs. Studies further indicated that when lower concentration of pigments were available, they remained completely surrounded by the binder;Thus leaving no space for the entry of corrosive agents. From these studies, it was concluded that the water borne paints could replace the conventional coatings, containing organic solvents. Therefore, water soluble epoxy-ester primers have to be employed in paints for developing eco- friendly coatings.展开更多
文摘鱼肉样品以Florisil硅藻土层析柱净化后,经气相色谱-电子轰击离子源-质谱法(GC-EI-MS)分析其中8种邻苯二甲酸酯(PAEs)含量:邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丙酯(DPrP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二戊酯(DPeP)、邻苯二甲酸二环己基酯(DCHP)、邻苯二甲酸二己酯(DHP)、邻苯二甲酸二(2-乙基己基)酯(DEHP).比较了外标和内标法定量,并确定苯甲酸苄基酯为内标物;优化了提取剂、吸附剂和洗脱剂的种类,以及洗脱体积等样品前处理方法;尤其对分析空白的控制问题进行了详细讨论;准确分析了5种鱼样品中此类物质含量.该方法的线性范围为50.0～800μg·L-1,相关系数(R)大于0.99986,相对标准偏差(Relative standard deviation,RSD)均小于12.7%,检测限(Limit of detection,LOD)低于3.66μg·L-1,样品的加标回收率为74.0%～113%.其线性范围、相关系数、准确度、精密度和LOD等指标均满足鱼肉中多种PAEs同时分析的要求.
文摘The corrosion behavior of water borne epoxy-ester primer coatings (10% - 50% PVCs) was evaluated through electrochemical techniques such as polarization and impedance spectroscopic (EIS) measurements. Studies were carried out for a longer duration of exposure extending up to 60 days in aqueous solution of NaCl (5%). Corrosion current (icorr), Corrosion potential (Ecorr), Coating resistance (Rc), Charge transfer resistance (Rct), Coating capacitance (Cc), Double layer capacitance (Cdl), break point frequency (fb), Water uptake (∮), diffusion coefficient (Dw) etc., indicated that 10% - 30% PVC coatings performed well in comparison to higher PVCs. Changes in the electrochemical characteristics were found to occur as a function of exposure time in all cases. The corrosion stability of the coatings were found to be greatly affected by the percentage of PVCs. Studies further indicated that when lower concentration of pigments were available, they remained completely surrounded by the binder;Thus leaving no space for the entry of corrosive agents. From these studies, it was concluded that the water borne paints could replace the conventional coatings, containing organic solvents. Therefore, water soluble epoxy-ester primers have to be employed in paints for developing eco- friendly coatings.
