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101.
C. Kubwabo I. Kosarac B. Stewart B.R. Gauthier K. Lalonde P.J. Lalonde 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(6):928-937
Human exposure to bisphenol A (BPA) has recently received special attention. It has been shown that exposure to BPA may occur through the consumption of beverages or foods that have been in contact with polycarbonate (PC) plastic containers or epoxy resins in food packaging. A BPA migration study was conducted using a variety of plastic containers, including polycarbonate baby bottles, non-PC baby bottles, baby bottle liners, and reusable PC drinking bottles. Water was used to simulate migration into aqueous and acidic foods; 10% ethanol solution to simulate migration to low- and high-alcoholic foods; and 50% ethanol solution to simulate migration to fatty foods. By combining solid-phase extraction, BPA derivatization and analysis by GC-EI/MS/MS, a very low detection limit at the ng l?1 level was obtained. Migration of BPA at 40°C ranged from 0.11 µg l?1 in water incubated for 8 h to 2.39 µg l?1 in 50% ethanol incubated for 240 h. Residual BPA leaching from PC bottles increased with temperature and incubation time. In comparison with the migration observed from PC bottles, non-PC baby bottles and baby bottle liners showed only trace levels of BPA. Tests for leachable lead and cadmium were also conducted on glass baby bottles since these represent a potential alternative to plastic bottles. No detectable lead or cadmium was found to leach from the glass. This study indicated that non-PC plastic baby bottles, baby bottle liners and glass baby bottles might be good alternatives for polycarbonate bottles. 相似文献
102.
K.A. Ehlert C.W.E. Beumer M.C.E. Groot 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(7):904-910
A comprehensive migration database was established for bisphenol A from polycarbonate baby bottles into water during exposure to microwave heating. Eighteen different brands of polycarbonate baby bottles sold in Europe were collected. Initial residual content of bisphenol A and migration after microwave heating were determined. Residual content of bisphenol A in the polycarbonate baby bottles ranged from 1.4 to 35.3 mg kg?1. Migration of bisphenol A was determined by placing a polycarbonate bottle filled with water in a microwave oven and heating to 100°C; the level of bisphenol A in the water was analysed by GC–MS. The procedure of microwave heating and analysis was repeated twice for the same bottle and, thus, three migration extracts were prepared for each test specimen. Migration of bisphenol A into water ranged from <0.1 to 0.7 µg l?1. There was no correlation between the amount of residual content of bisphenol A in the bottles and the migration of bisphenol A into water. Furthermore, there was no correlation between the amounts of bisphenol A in consecutive migration extracts. Data show that during three microwave-heating cycles of a baby bottle made from polycarbonate, microwave radiation had no effect on the migration of bisphenol A into water from polycarbonate. All levels found were well below the specific migration limit of 0.6 mg kg?1 specified for bisphenol A in Commission Directive 2004/19/EC. 相似文献
103.
《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(7):1225-1238
ABSTRACTBisphenol A (BPA; 4-[2-(4-hydroxyphenyl)propan-2-yl]phenol), a suspected endocrine disruptor with a weak estrogenic activity, is used in a variety of consumer products, including food-contact materials made of paper and cardboard products. Due to restrictions on the use of BPA because of its potential health risks, BPA is gradually being replaced by other bisphenols because no limitations exist for these substances. This study presents a method for the simultaneous analysis of BPA, bisphenol AF (BPAF), bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF) and bisphenol S (BPS) in paper and board products using gas chromatography-tandem mass spectrometry (GC-MS/MS). Paper samples were extracted by liquid extraction, as well as by Folch extraction, derivatised with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and the results compared. The developed method showed good linearity (R2 > 0.9965) and precision, yielding relative standard deviations (RSDs) of less than 16.6% for reproducibility and 19.8% for repeatability. The limits of detection and limits of quantification for the different bisphenols ranged from 0.23 to 2.70 µg kg–1 paper and from 0.78 to 9.10 µg kg–1 paper, respectively. Analysis of different paper products (recycled, virgin fibre) showed that all the analysed bisphenols were present in the samples, except for BPAF and BPB. A calculation of the ‘worst-case’ scenario assuming a maximum potential migration of 100% of the analytes into food showed that the analysed products can be assumed to be safe regarding the migration of bisphenols. 相似文献
104.
针对相似度碰撞引发证据融合结果错误的问题,提出一种新的证据融合方法。首先,提取证据的焦元序列特征并将其转化为排序矩阵以弥补证据相似度易碰撞的不足;其次,联合证据的排序矩阵和信息熵完成对证据权重的确定;最后,生成归一化证据（MAE）并使用Dempster融合公式将MAE融合n-1次获得最终的结果。基于在线的鸢尾花数据集对证据平均融合方法、余弦相似度证据融合方法、证据距离融合方法和证据信誉度融合方法进行了花类型识别准确性的F-Score对比,上述四种方法的F-Score分别为0.84、0.88、0.88和0.88,而所提方法的F-Score为0.91。实验结果表明,所提方法的决策准确率更高,融合结果更加可靠,能为证据决策提供了有效的解决方案。 相似文献
105.
利用分子印迹技术(MIT),以双酚A(BPA)为模板分子,邻氨基苯硫酚(ATP)为功能单体,通过自组装和电聚合方法制备双酚A分子印迹聚合膜电化学传感器,采用循环伏安法和交流阻抗法进行表征,并用于双酚A的检测,该研究结果为电化学聚合法制备分子印迹聚合膜,根据功能单体与模板分子的相互作用正确选择功能单体提供了理论基础。 相似文献
106.
试论在我国建设双酚A项目的技术和经济可行性 总被引：1，自引：0，他引：1
综述了双酚A的市场和技术的发展情况,对建设双酚A装置的经济性进行了简化的评价,提出了在我国适时建设双酚A装置的建议。 相似文献
107.
在局部极坐标系下,快速多级后向投影算法(FFBPA)可以以较低的采样率对子孔径成像,但在不同局部极坐标系之间需大量的2维图像域插值实现图像融合。相比极坐标系,图像融合在直角坐标系下更容易实现。但在直角坐标系下进行子孔径成像的奈奎斯特采样率较高,这将影响直角坐标系下的成像效率。该文针对此问题提出一种谱压缩技术,通过对距离时域和距离频域两次补偿,大幅压缩了直角坐标系下子孔径成像的方位谱宽度。该文算法具有堪比原始后向投影算法(BPA)的成像质量和优于FFBPA的计算效率,且能够应用于非线性轨道SAR。最后通过星载0.1 m仿真实验和机载0.2 m实测实验验证了算法的有效性。 相似文献
108.
109.
多源信息决策级融合是一种高层次、直接针对具体决策目标的融合,融合结果直接影响决策水平．针对决策级融合问题,提出了一种基于D-S证据理论的多类支持向量机融合方法．首先构造多个多类支持向量机分类器,然后采用一种新的基于成对类别概率的基本概率赋值方法,应用D-S证据理论将它们融合．仿真结果验证了该方法可以得到更高、更稳定的识别率． 相似文献
110.
研究了新试剂三溴偶氮溴膦（4－BPA－TB）与钡（Ⅱ）的显色反应。本法可用于人发中微量钡的测定。 相似文献