The authors would like to thank the French National Association of Research and Technology (ANRT) for funding this research through the PhD grant awarded to Dr. Kenza Bacha.

注意:使用前请咨询所有相关的材料安全数据表（MSDS）。运营商需要配备个人防护装备，包括手套，礼服和护目镜。在使用前，新鲜试剂需要被保存在冰箱中。氧化燃料中含有丰富的腐蚀性酸性物质。它们不能被储存在金属瓶中，并必须存储在合适的玻璃容器中的冷藏库，用有限的顶部空间的空气，在垂直位置，以避免燃料和烧瓶帽之间的接触。在冰箱保持在6℃。氧化生成，可能会引起呼吸道刺激挥发性氧化产物。因此，所有的氧化实验需要提取橱下进行。 1.高级氧化过程反应器1 注意:反应器1用于进行油酸甲酯的受控氧化（MO），单不饱和的代表性商业FAME 3的模型分子&lt;/ SUP&gt;。旨在通过以下步骤监测MO氧化的测试。 <ol><li> 确定平均诱导期（IP）的 <ol><li>根据标准测试方法4制备反应容器和测量细胞。 </li><li>使用压缩空气燃料引入前的反应容器中取出可能的灰尘或污染物。 </li><li>补块A的反应容器:1至4用7ml用吸管油酸甲酯的新鲜燃料的样品。 </li><li>配置测试。 <ol><li> A座的加热设定温度为110℃（±0.3℃）。 </li><li>设置的空气流率，以通过样品至10升/小时进行鼓泡。 </li><li>设置截流标准要么400μS/ cm的电导率阈值或由软件确定的IP。当达到这两个标准之一测试停止。 </li></ol></li><li>输入名称，并在每个块A的样品的参考该软件。 </li><li>通过按下"开始"按钮启动测试。 注意:这意味着通过样品同时鼓入空气，提高加热块的温度（加热时间为120℃的设定点温度约45分钟）。当达到关断标准，空气鼓泡和块加热被自动中断。 </li><li>提取来自加热块的反应容器。 </li><li>手动彻底搅拌反应容器中的内容，以均匀的燃料组合物。转移的每个反应容器的内容物到10ml玻璃烧瓶中，并垂直放置玻璃烧瓶在冰箱中抽出之后。 </li><li>确定使用图2中所示的切线交点的方法中的导电性信号的诱导期（IP）。诱导期是由外推基线（T1）和所述的交叉点的位置定从曲线拐点（T2）上的x轴绘制的切线。 </li><li>计算使用IP测量是根据IP分散体的10％以内的平均IP（ 平均 ）:IP 平均 =ΣIP 有效 / n，这里的IP 有效表示IP地址的分散和n的数量的10％内的IP测量。 </li></ol></li><li> 产生具有不同氧化水平样本 <ol><li>使用Block B，重复步骤1.1.-1.5。然而，通过表示上述IP AVG在步骤1.1.9确定的结束时间等于4倍修改遮断标准。 </li><li>提取的"手动"的第一个反应从加热块在0.5容器中的IP地址，在IP的第二反应容器中，在2倍的IP地址和在4倍的IP第四和最后的反应器中的第三个反应容器中。 </li><li>对于每一个反应容器中，手动彻底搅动conten容器的TS具有均匀的样品。传送整个内容在10毫升玻璃烧瓶中，标记每个样品（0.5 IP，IP 2的IP和4个IP，分别）和垂直放置玻璃烧瓶在冰箱中抽出之后。 </li></ol></li></ol><img alt="图2" src="/files/ftp_upload/54361/54361fig2.jpg" /> 图2.诱导期测定切线交会法;在110℃下测试的油酸甲酯。诱导期是由外推基线（T1）和从曲线拐点（T2）上的x轴绘制的切线的交叉点的位置给出。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig2large.jpg" target="_blank">请点击查看一个更大的版本这个数字。</a> <ol start="3"><li> 分析生成的样本 <ol><li>确定油酸甲酯的谭以增加氧化氮采样使用方法μTAN通货膨胀的阶段（从ASTM D664 9得出）。 <ol><li>冲洗所有部件与样品（样品容器，电极，和磁力搅拌器）用超纯水随后异丙醇接触。 </li><li>称取将2g样品，并将其放置在测量容器中。 </li><li>稀释样品中在测量容器10克异丙醇。 </li><li>当达到等当点，直至逐渐添加在异丙醇中稀释的0.1mol / L的KOH的溶液。这是通过一个显著电位变化（高于9毫伏），用玻璃电极测定指示。 </li><li>报告在每克燃料毫克KOH样品的TAN（毫克KOH /克）。 </li></ol></li><li>分析在通过GC-MS增加氧化阶段采样油酸甲酯。 <ol><li>注入1微升样品放入装有FFAP柱的GC-MS（60米，0.250mmol毫米，0.25微米），使用的1:75分流比。 </li><li>请执行以下加热程序柱:40℃下进行10分钟，然后在5℃/分钟加热至100℃，最后在1℃/分钟至250℃。 </li><li>使用质谱仪的参数如下:电子电离源的潜能:70伏特 - 质量范围:M / Z = 10〜400 - 全扫描模式。 </li><li>报告气相色谱谱图并继续显著峰的鉴定。 </li></ol></li></ol></li></ol> 2.高级氧化过程反应堆2 注:反应器2被用来在免费的生物柴油，柴油（B0）和油菜籽甲基酯（RME）进行连续的氧化循环。这些测试旨在通过​​以下步骤监测燃料氧化。 <ol><li> 执行第一个氧化循环。 <ol><li>配置测试。 <ol><li>使用用户界面设置的加热温度至150℃。使用用户接口单元中的压力设定为7巴。设置关闭CRiterion:达到最大压力的10％的压力降（△P）。 </li></ol></li><li>制备试验电池。除去可能存在的灰尘或使用丙酮浸泡实验室雨刷污染物和更换密封环。 <ol><li>用移液管将5ml燃料样品的填充细胞。用螺帽接着一个保护锁定盖关闭检测单元。 </li></ol></li><li>通过在反应器2的用户界面按下"RUN"按钮启动测试。 注意:首先，将细胞被加压与氧，通过供给线注入，则该信元被减压经抽出导管撤离气体。然后，用氧气重新加压。当头部空间压力达到7条，测试开始。温度升高到150℃，直到达到一个稳定的最大值的压力与温度一起上升。 </li><li>使用计算机在1秒为间隔的压力变化，直到舒记录达到TOFF标准。此时，测量和小区加热自动停止。 </li><li>等待15分钟，直到温度20℃左右降低。 </li><li>减压使用用户界面的测试单元。此吹扫允许达到在细胞大气压。打开保护盖，将螺丝帽。 </li></ol></li><li> 执行"x"表示连续的氧化循环。 <ol><li>重复步骤2.1.3至2.1.6所期望的"X"倍。 </li><li>在的"×"的测试结束时，所有剩余的细胞用吸管被氧化的燃料的转移至10毫升玻璃烧瓶中，并垂直放置玻璃烧瓶在冰箱中。 </li><li>使用用丙酮浸泡实验室雨刷清洗细胞。 </li></ol></li><li> 分析生成的样本 <ol><li>分析使用FTIR-ATR样品。 <ol><li>使用清洁用乙醇浸泡实验室纸ATR钻石细胞。 </li><li> CONFigure软件参数:设置100次扫描来构建FTIR光谱，在4厘米固定分辨率-1以及600〜4000 -1设置的光谱范围。 </li><li>提取从冰箱燃料烧瓶中，并以均匀的燃料组合物彻底搅拌其内容。 </li><li>样品用移液管，并放置在室温下的水平的ATR金刚石细胞的液滴，然后启动分析10微升的燃料从燃料瓶。 </li></ol></li></ol></li></ol>

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The authors have nothing to disclose.

一种先进的氧化协议（AOP），使用两个氧化反应器（反应器1和反应器2）在这项工作中开发的。该协议被应用于研究商用柴油和生物柴油燃料的氧化以及纯试剂如油酸甲酯。在本节中，我们讨论的协议及其应用的某些方面。 当使用反应器1和反应器2作为时效装置，氧化样品的均匀性，应考虑作为氧化能导致不溶产品，可以粘到装置的内表面的形成。那些不能与该装置的冷却后的吸移管完全收集。即使在样品收集后，两相有时可以在高氧化水平观察到。在这样的情况下，将上清的一部分被收集要分析，但不能被认为是代表整个被氧化的样品。此外，所收集的样本不包含Intermediate物种是重要评估氧化动力学。氧化过程中样品的在线分析可能有助于解决这一问题。以前的作品已经实现利用不同的反应器烃氧化过程在线分析，如搅拌反应器16,17或高压釜18。这些反应器允许氧化产物中的液体，并在一个较高的采样频率的气体相同时监视。它们可以覆盖较宽范围的氧化条件（ 例如 ，空气流率，温度，混合速度）。然而，它们需要特定和昂贵的测试设备，并且更费时。此外，由于它们的设计和测试条件与标准氧化稳定性试验不同，这是难以精确地建立在标准和替代测试燃料的反应性之间的关系。 反应器1或反应釜2典型的氧化试验产生低于5毫升和7毫升，respectiv低伊利。这些小批量不足以在最佳条件下进行多种分析。例如，传统的总酸值分析至少需要20克的分析样品（ASTM D664）的这也解释了在这项工作中使用μTAN的。 该IP计算（反应器1）基于切线交会法。第二个可能的方法是计算使用二次衍生物4，其中的IP是通过在第二导数的最大指示的诱导期。然而，该方法是有限的，当电导率信号是波动频繁发生。使用切线法允许用户克服此限制。然而，相切的方法是依赖于用户的，因为它依赖于用户绘制切线。在目前的研究中，确定由所有样品相同的操作者进行。进行重复分析，以验证结果的准确性。 Accordi纳克到的实验结果，在诱导期精度（IP p）的下列方程的IP P（小时）= 0.15的IP-0.37依赖于IP，具有IP是诱导期，在协议与约0.6小时的精度以前报道在标准条件5。 的TAN为酸性物质形成毛指示器，然而，μTAN测量精度仍依赖于样品的量，特别是，对于具有低酸值的样品。此外，TAN不提供任何分子信息。然而，这是因为在氧化过程中，TAN增加和不溶性沉积物的形成之间有很强的关系已在文献16,19,20已经报道了一个有趣的技术。因此，氧化的MO样品的更详细的描述，用GC-MS进行。 关于由GC-MS技术，该系统应检查通过分析样品之前注入溶剂（空白）可能的污染。作为这种技术是非常敏感的，微量化合物的形成可以被监控。通过这种方式，不存在任何寄生虫峰可以验证。 取其的分析技术，样品表征应当尽快氧化过程之后进行。事实上，被氧化的样品是高度不稳定的和长的贮存时间会导致在样品的成分的变化。如果存储是不可避免的，要注意使用玻璃瓶密封选择并将它们存储在低温下（ 例如 ，6℃）。 总之，AOP允许用户监控几个单和多组分系统的氧化过程。首先，由通过诱导期表征全球反应性，那么，通过在受控条件下产生的氧化样品。几个鉴定TEChniques如GC-MS，红外，或μTAN可以与所产生的样本被用来监控其性能和化学成分的变化。研究结果提供了有关氧化动力学，主要的降解途径和氧化的产品和丰富的原始信息。此外，AOP表示一个非常有用的工具来研究的氧化条件，如温度，氧化时间和氧浓度的影响。这项工作提供了一个有效和有前景的方法，可能是使用的是研究交通运输或生物应用氧化动力学。

氧化稳定性是评价燃油质量的标准。燃料的氧化稳定性可通过几种方法例如诱导期，过氧化物，酸和不溶物来监测。诱导期（IP）是在氧化过程期间的反应是缓慢的，开始时的期间，由于反应中间体的低浓度或抗氧化剂的存在。 图1表示的烃的氧化的简化机构。据报道1,2-，在液相烃的氧化主要如下的自由基机理。萌生，扩展和终止:它按三个步骤进行。在起始步骤，自由基通过夺氢反应从初始烃（RH）下或氢过氧化物在燃料（R1A-c）中已存在的分解而形成的。二 - 氧的除了在过氧化formatio所形成的自由基的结果n按反应（R 2）。传播的步骤进行主要是通过过氧化物路线。所形成的过氧化与由夺氢或通过加入生产氢过氧化物或聚过氧化物的初始烃反应，根据反应（R3A）和（器R3b）表示。氢过氧化物的分解生成不同的氧化产物，主要是，醇，羰基，环氧化物和烷烃（R4）。当稳定的产品通过自由基重组（R5-R7）形成时发生终止步骤。在这项工作中，我们开发了一种过程监测用两个现有的氧化反应器中的氧化过程。 <img alt="图1" src="/files/ftp_upload/54361/54361fig1.jpg" /> 图1.简化的碳氢化合物氧化机理的机制代表的碳氢化合物氧化包括几个已知的步骤全球化的关键步骤 :开始传播和终止。氏的身影已重印从8许可，版权所有2015年美国化学学会。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 使用的Rancimat设备（反应器1）进行加速氧化。本设备是按照标准EN 15751 3号反应堆1配备有两个加热块用于名人堂和含有柴油燃料的标准测试: 加热块A和加热块B每个加热块包含4个反应釜，从编号1至4个，连接到4个测量细胞。的挥发性物质的一部分，在氧化过程中产生的空气循环夹带并通过装满蒸馏水的测量细胞捕获。在水电导率信号的变化被连续地监视。诱导期（IP）的特征在于导电性的突然上升尤其是挥发性酸物质ssociated。有关标准方法的进一步细节可在别处4,5被发现。 所述PetroOxy装置（反应器2）也被用来执行加速燃料氧化试验。此设备是根据ASTM D 7545和ASTM D 7525标准，6,7-用于中间馏出物和汽油燃料的氧化稳定性的测量。由该装置所测量的诱导期被定义为达到在试验电池顶部空间测量的10％的压力降（△P）所必需的时间。 这些技术已被大量地用于中间馏分燃料的氧化稳定性的标准表征以及用于氧化动力学研究8,9 10,11。

<table border="0" cellpadding="0" cellspacing="0" width="1264">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">Rancimat&#160;</td>
			<td style="width:117px;">Metrohm</td>
			<td style="width:225px;">Rancimat 843</td>
			<td style="width:695px;">Standard test apparatus for diesel and biodiesel oxidation stability&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">PetroOxy</td>
			<td style="width:117px;">Petrotest&#160;</td>
			<td style="width:225px;">&#160;13-3000</td>
			<td>Standard test apparatus for diesel and biodiesel oxidation stability&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">FTIR spectrometer</td>
			<td style="width:117px;">Brucker</td>
			<td style="width:225px;">Brucker IFS66</td>
			<td>Apparatus for chemical composition analysis through chemical functions identification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">Total acid number titrator</td>
			<td style="width:117px;">Metrohm</td>
			<td>Titrino Plus 848&#160;</td>
			<td>Test apparatus for diesel and biodiesel oxidation stability&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gas Chromatograph</td>
			<td style="width:117px;">Agilent</td>
			<td>6890 Agilent GC/MS</td>
			<td>Analatical chemistry technique used to separate the compounds present in a sample</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gas Chromatography column</td>
			<td style="width:117px;">Agilent</td>
			<td>DB-FFAP column&#160;</td>
			<td>Component of Gas Chromatogram that separates the molecules</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mass Spectrometer</td>
			<td style="width:117px;">Agilent</td>
			<td style="width:225px;">5973 inert mass spectrometer</td>
			<td>Analytical chemistry technique used to identify the compounds present in a sample</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Methyl Oleate 99%</td>
			<td>SIGMA ALDRICH&#160;</td>
			<td style="width:225px;">311111&#160;ALDRICH</td>
			<td>Pure reagent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:228px;">EMAG-free ultra-low sulfur diesel</td>
			<td style="width:117px;">Total ACS</td>
			<td>CEC RF-06-03</td>
			<td>Commercial Diesel fuel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">Rapeseed methyl Ester</td>
			<td style="width:117px;">ASG</td>
			<td style="width:225px;">Biodiesel 3826 00 10</td>
			<td>Commercial Biodiesel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">Isopropanol &#62; 99,9 %</td>
			<td style="width:117px;">VWR</td>
			<td style="width:225px;">84881.290</td>
			<td>Solvent for Total Acid Number determination</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:228px;">KOH 0,1M in isopropanol</td>
			<td style="width:117px;">VWR</td>
			<td style="width:225px;">1.05544.1000</td>
			<td>Titration agent for Total Acid Number determination</td>
		</tr>
	</tbody>
</table>

original experimental approach for assessing transport fuel stability

的燃料氧化稳定性的研究是为未来的燃料的发展的一个重要问题。柴油和煤油燃料系统已经历了多次技术变革实现环境和经济的要求。这些发展已经导致越来越严重的情况下，其适合常规和替代燃料需要加以解决。例如，介绍了作为生物柴油的脂肪酸甲酯（脂肪酸甲酯）更容易被氧化，并可能导致沉积物的形成。虽然存在多种方法来评价燃料稳定性（诱导期，过氧化物，酸和不溶物），无技术允许一个监视实时氧化机理，并测量氧化中间体，可能导致形成沉积物的形成。在这篇文章中，我们开发了基于两个现有反应堆的高级氧化过程（AOP）。此过程允许不同的氧化条件，并在显示器的模拟由宏观参数，如总酸值（TAN）和先进的分析方法，如气相色谱质谱的装置的氧化进展ING（GC-MS）和傅立叶变换红外 - 衰减全反射光谱（FTIR-ATR）。我们成功地应用AOP获得的模型分子（油酸甲酯）和商用柴油和生物柴油燃料的氧化动力学的深入了解。这些发展过程中的物流和船上利用代表了燃料质量监测的关键战略。

反应器1使用AOP研究油酸甲酯氧化 油酸甲酯的IP（MO）的混合物在110℃下三次测定，具有小于5％（绝对偏差0.06小时）的错误。根据切线交会法IP测量表明1.8小时的平均IP的时间。 AOP的根据上述协议，在0.5的IP，IP 2的IP和4个IP，分别实现氧化的样品进行。 图3呈现的总酸值的氧化过程期间的变化。谭测量允许的燃料的总体氧化状态的评估。新鲜的MO的TAN大于TAN装置的定量下限，因此可以被认为是微不足道的。从0到0.5的IP，在TAN仍然很低（大约0.1毫克KOH /克），然后从0.5增大至1我由8倍大的因数P。在4个IP的TAN大于0.5的IP显示TAN与氧化时间呈指数增长高出约52倍。这种行为表明，酸性物质的形成是氧化初期政权期间相对较慢。然而，它成为在中级和高级氧化机制显著: 即从0.5至IP和IP后。 <img alt="图3" src="/files/ftp_upload/54361/54361fig3.jpg" /> 图3.在从0 IP油酸甲酯不同的氧化水平，以4总酸值（TAN）的变化的IP。与氧化进度油酸甲酯增加了总酸值。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 总离子电流（TIC），在GC-M收购小号耦合，在图4中提出了在MO样品的各种氧化阶段。 TIC，这相当于一个GC / FID迹，表示出来的气相色谱仪的整体信号。 <img alt="图4" src="/files/ftp_upload/54361/54361fig4.jpg" /> 在不同的氧化水平从0 IP 4个IP MO样本图4.气相色谱图。气体色谱上呈现的有关的氧化产物的几个新的峰的形成大范围的保留时间（0-180分钟）总体比较。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 在新的MO（0 IP），已经有几座山峰，但具有非常低的强度，从最有可能的杂质。作为标准的纯度，MO是ABO已经99％，所有杂质的浓度的总和是小于1％。与杂质相关的峰可以被识别，这凸显了这一分析技术的灵敏度。所有的色谱归一化到相同的比例来定性比较的峰的相对强度。有趣的是，以通知的几个峰强度为0的IP（新鲜样品）的增加4个IP（高度氧化样品）。此外，在中形成高氧化水平在最初的色谱图中不存在的某些物种有逐渐增加强度。为方便阅读， 图7呈现只从0到30分钟的范围内。 MO，具有115分钟的保留时间，不会出现在该时间范围内。用质谱（MS）耦合使得用户能够执行氧化产物的分子鉴定。鉴定于在4倍的IP氧化在MO样品进行。事实上，后者的SAMP<html>乐介绍，几乎所有的早期阶段具有较高浓度所产生的氧化产物。 为在色谱（ 图5）的各峰，相关的化合物的鉴定是通过实验质谱和理论值（NIST数据库）之间的比较的。例如，具有26.5分钟的保留时间的峰，根据质谱鉴定为甲基-6-庚烯酸乙酯。结果表明，在氧化过程中甲基-6-庚烯酸乙酯，从新鲜产品最初不存在，就产生了。定性，0.5至4倍的IP，相关联的峰上升通过的约10倍的强度。 在整个色谱图（从0到190分钟）得到的结果突出显示的形成，然后分子，原本不存在的浓度的上升，随着氧化时间的增加。 jove_content"FO:保持-together.within页="1"&gt;所有分子的鉴定表明各种化学部分的在氧化过程中形成的第一，通过分子裂解，形成几个短链分子，如C 5。至C 8烯烃，C 6至C 8的烷烃，C 7 -C 8甲酯与周围90-120min保留时间通过分子氧与烷基或氢过氧化物的直接反应，C 8 -C 9醛，C 8 - C分别在类似的保留时间形成含有其他氧化的官能团（ 例如，醇或环氧化物）9甲基酯。酸甲酯，并且与较长的链长醛还保留时间发现大于30分钟，2癸烯醛和2- undecenal这样。 一些与GC-MS目前的工作中确定的产品都是用W一致Hat已经在文献中报道。例如，Berdeaux 等人 12稍有不同的实验条件（180℃，15小时的加热，没有氧气）下进行的MO的氧化。一种分离进行以除去非极性化合物和极性馏分注入GC-MS装置。作者发现各种醛和甲酯，从而与我们的结果是一致的。因为所述非极性馏分未表征这些作者，没有比较是可能涉及烷烃和烯烃。我们的研究结果与文献结果的一致性突出用于研究燃料和生物燃料的氧化动力学的AOP的潜力。 <img alt="图5" src="/files/ftp_upload/54361/54361fig5.jpg" /> 图5. MO的气相色谱氧化在4个IP产品的分子鉴定为0的保留时间范围内- 30分钟（T运图），并专注于甲基-6-庚烯酸峰（下图）在上质谱对应于实验数据和下一个理论质谱（NIST数据库）。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig5large.jpg" target="_blank">请点击此处查看这个大版本数字。</a> 反应堆2使用AOP研究生物柴油的氧化 图6分别给出B0的样品，并按照1，4和6的氧化循环（B0-1）（B0-4）和（B0-6）氧化的B0。从透明的氧化过程中的燃料颜色变为淡黄棕色，然后。这种变化是由于极性化合物的形成。这些产品的分子量与氧化水平沿增大。氧化B0样品显示的高分子构成的黑色粘稠相的形成重量极产品。 <img alt="图6" src="/files/ftp_upload/54361/54361fig6.jpg" /> 图6. B0和反应器2继在氧化过程中B0 反应堆2.颜色变化1,4和6次氧化氧化B0样品 。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 图7呈现的FTIR氧化期间在1,4和6次在反应器2中确定的RME组合物进行了研究三个区域（ 图7）的演变。在[800-1,400 -1]中的区R 1观察到的峰暗示CO和COC键的存在，可以归因于酒精，环氧和环氧乙烷的功能。 R 2表示极性产物如酸，醛，KET形成那些和酯。 1650和1760厘米之间确定的峰-1与氧化水平拓宽一起。并行地，双键（C = CH）的一个显着的下降表示这里由峰在3010厘米-1观察到13:近30％的转化率，90％，并观察几乎100％后1,4和6分别运行在反应器2。这种趋势表明在R 1和R 2如下所述双键的不饱和脂肪酸甲酯的转化所述的氧化产物的形成。 <img alt="图7" src="/files/ftp_upload/54361/54361fig7.jpg" /> 图7. FTIR光谱对RME和在反应器2中被氧化的RME样品下面1,4和6的氧化循环。FTIR光谱新鲜和氧化RME的上一个宽波长范围的总体比较（600-3,800 -1）呈递的变化与T相关的吸收信号他氧化。这个数字已重印从8许可，版权所有2015年美国化学学会。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig7large.jpg" target="_blank">请点击此处查看本图的放大版本。</a> 图8表示下面的1,4和6的氧化循环B0和氧化B0的FTIR分析。三个区域中示出的 R 1（600 - 1300厘米-1）中，R 2（1600 - 1800厘米-1）和R 3（3000 - 3600厘米-1）。在B0-1，B0-4和B0-6的区域R 2中检测到羰基键（C = O）。在1710厘米-1与氧化水平增加使用了羰基键的面积为氧化水平14,15的比较，作为羰基的峰。该峰归因于极性产物醛，酮，酸，例如形成。峰值我n中的区域R 3表示（OH）官能团的形成，这表明醇和酸的存在。 <img alt="图8" src="/files/ftp_upload/54361/54361fig8.jpg" /> 图8. FTIR光谱在反应器2 B0和氧化B0样品下面1,4和6的氧化循环的FTIR光谱新鲜和氧化B0的对宽波长范围总体比较。（600 - 3800厘米-1）呈递的变化与氧化相关的吸光度信号。这个数字已重印从8许可，版权所有2015年美国化学学会。 <a href="http://www.jove.com/files/ftp_upload/54361/54361fig8large.jpg" target="_blank">请点击此处查看本图的放大版本。</a> 总之，AOP施加此处商用柴油和的biod的氧化iesel允许监视这些燃料的全球氧化速率和若干极性含氧化合物的整个氧化过程上的宽分子量范围的形成。根据上B0燃料的FTIR分析，羰基产品，主要酮和醛，少量在第一氧化循环（B0-1）之后形成的。后6氧化循环（B0-6）时，褐色和更粘样品表示一个更严重的氧化水平。该FTIR分析提供了目前主要的官能团，包括极性氧化产物如醇，酸和内酯的进一步认识。 观察在RME较高的氧化速度相比，B0。上的RME FTIR结果表明不饱和分子的（峰在3010厘米-1）的转化率和的极性氧化产物的形成。因此，这表明在RME不饱和分子被驱动的氧化过程，并导致更高的氧化速率与B0相比较。

Watch this Scientific Journal Video about Original Experimental Approach for Assessing Transport Fuel Stability at JoVE.com

Original Experimental Approach for Assessing Transport Fuel Stability

运输燃料的氧化稳定性已经成为未来发展的燃料关注。 这项工作提出了评估使用两种不同的反应器燃料的稳定性由IFP能源新军开发的原始方法。这种方法成功地应用于获得氧化动力学模型和分子和商业燃料的途径进行了深入的了解。

评定运输燃料的稳定性原始实验方法

The study of fuel oxidation stability is an important issue for the development of future fuels. Diesel and kerosene fuel systems have undergone several ...

original-experimental-approach-for-assessing-transport-fuel-stability

Research

JoVE Journal

Chemistry

9.2K 次观看.  Institut de Science des Matériaux de Mulhouse. 运输燃料的氧化稳定性已经成为未来发展的燃料关注。 这项工作提出了评估使用两种不同的反应器燃料的稳定性由IFP能源新军开发的原始方法。这种方法成功地应用于获得氧化动力学模型和分子和商业燃料的途径进行了深入的了解。 

视频: Original Experimental Approach for Assessing Transport Fuel Stability

A Guided Materials Screening Approach for Developing Quantitative Sol-gel Derived Protein Microarrays

Microarrays have found use in the development of high-throughput assays for new materials and discovery of small-molecule drug leads. Herein we describe a guided material screening approach to identify sol-gel based materials that are suitable for producing three-dimensional protein microarrays. The approach first identifies materials that can be printed as microarrays, narrows down the number of materials by identifying those that are compatible with a given enzyme assay, and then hones in on optimal materials based on retention of maximum enzyme activity. This approach is applied to develop microarrays suitable for two different enzyme assays, one using acetylcholinesterase and the other using a set of four key kinases involved in cancer. In each case, it was possible to produce microarrays that could be used for quantitative small-molecule screening assays and production of dose-dependent inhibitor response curves. Importantly, the ability to screen many materials produced information on the types of materials that best suited both microarray production and retention of enzyme activity. The materials data provide insight into basic material requirements necessary for tailoring optimal, high-density sol-gel derived microarrays.

A guided material screening approach to develop sol-gel derived protein doped microarrays using an emerging pin-printing method of fabrication is described. This methodology is demonstrated through the development of acetylcholinesterase and multikinase microarrays, which are used for cost-effective small-molecule screening.

在导游的带领下材料的筛选方法定量溶胶 - 凝胶蛋白芯片开发

Microarrays have found use in the development of high-throughput assays for new materials and discovery of small-molecule drug leads. Herein we describe a ...

科研

化学

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach

Bone morphogenetic protein 2 (BMP-2) is a growth factor embedded in the extracellular matrix of bone tissue. BMP-2 acts as trigger of mesenchymal cell differentiation into osteoblasts, thus stimulating healing and de novo bone formation. The clinical use of recombinant human BMP-2 (rhBMP-2) in conjunction with scaffolds has raised recent controversies, based on the mode of presentation and the amount to be delivered. The protocol presented here provides a simple and efficient way to deliver BMP-2 for in vitro studies on cells. We describe how to form a self-assembled monolayer consisting of a heterobifunctional linker, and show the subsequent binding step to obtain covalent immobilization of rhBMP-2. With this approach it is possible to achieve a sustained presentation of BMP-2 while maintaining the biological activity of the protein. In fact, the surface immobilization of BMP-2 allows targeted investigations by preventing unspecific adsorption, while reducing the amount of growth factor and, most notably, hindering uncontrolled release from the surface. Both short- and long-term signaling events triggered by BMP-2 are taking place when cells are exposed to surfaces presenting covalently immobilized rhBMP-2, making this approach suitable for in vitro studies on cell responses to BMP-2 stimulation.

We describe a method for accomplishing efficient immobilization of BMP-2 on surfaces. Our approach is based on the formation of a self-assembled monolayer to achieve the covalent binding of BMP-2 via its free amine residues. This method is a useful tool to study signaling at the cell membrane.

BMP-2的共价结合利用表面上的自组装单层膜法

Bone morphogenetic protein 2 (BMP-2) is a growth factor embedded in the extracellular matrix of bone tissue. BMP-2 acts as trigger of mesenchymal cell ...

An Inverse Analysis Approach to the Characterization of Chemical Transport in Paints

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in understanding contaminant mass transport and the ability to decontaminate materials. If a material is contaminated, over time, the transport of highly toxic chemicals (such as chemical warfare agent species) out of the material can result in vapor exposure or transfer to the skin, which can result in percutaneous exposure to personnel who interact with the material. Due to the high toxicity of chemical warfare agents, the release of trace chemical quantities is of significant concern. Mapping subsurface concentration distribution and transport characteristics of absorbed agents enables exposure hazards to be assessed in untested conditions. Furthermore, these tools can be used to characterize subsurface reaction dynamics to ultimately design improved decontaminants or decontamination procedures. To achieve this goal, an inverse analysis mass transport modeling approach was developed that utilizes time-resolved mass spectroscopy measurements of vapor emission from contaminated paint coatings as the input parameter for calculation of subsurface concentration profiles. Details are provided on sample preparation, including contaminant and material handling, the application of mass spectrometry for the measurement of emitted contaminant vapor, and the implementation of inverse analysis using a physics-based diffusion model to determine transport properties of live chemical warfare agents including distilled mustard (HD) and the nerve agent VX.

In this paper, a procedure for quantifying the mass transport parameters of chemicals in various materials is presented. This process involves employing an inverse-analysis based diffusion model to vapor emission profiles recorded by real-time, mass spectrometry in high vacuum.

一个反分析方法化工运输的油漆表征

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in ...

Quantitative Detection of Trace Explosive Vapors by Programmed Temperature Desorption Gas Chromatography-Electron Capture Detector

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples.

Trace explosive vapors of TNT and RDX collected on sorbent-filled thermal desorption tubes were analyzed using a programmed temperature desorption system coupled to GC with an electron capture detector. The instrumental analysis is combined with direct liquid deposition method to reduce sample variability and account for instrumentation drift and losses.

定量检测痕量爆炸物蒸气通过程序升温脱附 - 气相色谱 - 电子捕获检测器

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive ...

Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability

Analytical ultracentrifugation (AUC) can be used to study reversible interactions between macromolecules over a wide range of interaction strengths and under physiological conditions. This makes AUC a method of choice to quantitatively assess stoichiometry and thermodynamics of homo- and hetero-association that are transient and reversible in biochemical processes. In the modality of sedimentation equilibrium (SE), a balance between diffusion and sedimentation provides a profile as a function of radial distance that depends on a specific association model. Herein, a detailed SE protocol is described to determine the size and monomer-monomer association energy of a small membrane protein oligomer using an analytical ultracentrifuge. AUC-ES is label-free, only based on physical principles, and can be used on both water soluble and membrane proteins. An example is shown of the latter, the small hydrophobic (SH) protein in the human respiratory syncytial virus (hRSV), a 65-amino acid polypeptide with a single &#945;-helical transmembrane (TM) domain that forms pentameric ion channels. NMR-based structural data shows that SH protein has two protonatable His residues in its transmembrane domain that are oriented facing the lumen of the channel. SE experiments have been designed to determine how pH affects association constant and the oligomeric size of SH protein. While the pentameric form was preserved in all cases, its association constant was reduced at low pH. These data are in agreement with a similar pH dependency observed for SH channel activity, consistent with a lumenal orientation of the two His residues in SH protein. The latter may experience electrostatic repulsion and reduced oligomer stability at low pH. In summary, this method is applicable whenever quantitative information on subtle protein-protein association changes in physiological conditions have to be measured.&#160;&#160;

Sedimentation equilibrium (SE) can be used to study protein-protein interactions in a physiological environment. This manuscript describes the use of this technique to determine the effect of pH on the stability of a homo-pentamer formed by the small hydrophobic (SH) protein encoded by the human syncytial respiratory virus (hRSV).

小型低聚物形成膜蛋白的沉降平衡:组氨酸质子对五聚体稳定性

Analytical ultracentrifugation (AUC) can be used to study reversible interactions between macromolecules over a wide range of interaction strengths and ...

Transport of Surface-modified Carbon Nanotubes through a Soil Column

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, electronics and biomedical applications. Due to their accelerating production and use, CNTs constitute a potential environmental risk if they are released to soil and groundwater systems. It is therefore essential to improve the current understanding of environmental fate and transport of CNTs. The transport and retention of CNTs in both natural and artificial media have been reported in literature, but the findings widely vary and are thus not conclusive. There are a number of physical and chemical parameters responsible for variation in retention and transport. In this study, a complete procedure of selected multiwalled carbon nanotubes (MWCNTs) is presented starting from their surface modification to a complete set of laboratory column experiments at critical physical and chemical scenarios. Results indicate that the stability of the commercially available MWCNTs are critical with their attached surface functional group which can also influence the transport and retention of MWCNT through the surrounding medium.

Surface properties of a nanoparticle are important for their interaction with the surrounding medium. Therefore the surface modification of carbon nanotubes can be critical for their transport and retention through porous media. Here, lab scale column experiments are used to understand the possible transport and retention of these nanoparticles.

表面修饰碳纳米管通过土柱运输

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, ...

Glycan Node Analysis: A Bottom-up Approach to Glycomics

Synthesized in a non-template-driven process by enzymes called glycosyltransferases, glycans are key players in various significant intra- and extracellular events. Many pathological conditions, notably cancer, affect gene expression, which can in turn deregulate the relative abundance and activity levels of glycoside hydrolase and glycosyltransferase enzymes. Unique aberrant whole glycans resulting from deregulated glycosyltransferase(s) are often present in trace quantities within complex biofluids, making their detection difficult and sometimes stochastic. However, with proper sample preparation, one of the oldest forms of mass spectrometry (gas chromatography-mass spectrometry, GC-MS) can routinely detect the collection of branch-point and linkage-specific monosaccharides ("glycan nodes") present in complex biofluids. Complementary to traditional top-down glycomics techniques, the approach discussed herein involves the collection and condensation of each constituent glycan node in a sample into a single independent analytical signal, which provides detailed structural and quantitative information about changes to the glycome as a whole and reveals potentially deregulated glycosyltransferases. Improvements to the permethylation and subsequent liquid/liquid extraction stages provided herein enhance reproducibility and overall yield by facilitating minimal exposure of permethylated glycans to alkaline aqueous conditions. Modifications to the acetylation stage further increase the extent of reaction and overall yield. Despite their reproducibility, the overall yields of N-acetylhexosamine (HexNAc) partially permethylated alditol acetates (PMAAs) are shown to be inherently lower than their expected theoretical value relative to hexose PMAAs. Calculating the ratio of the area under the extracted ion chromatogram (XIC) for each individual hexose PMAA (or HexNAc PMAA) to the sum of such XIC areas for all hexoses (or HexNAcs) provides a new normalization method that facilitates relative quantification of individual glycan nodes in a sample. Although presently constrained in terms of its absolute limits of detection, this method expedites the analysis of clinical biofluids and shows considerable promise as a complementary approach to traditional top-down glycomics.

This article presents an enhanced form of a novel bottom-up glycomics technique designed to analyze the pooled compositional profile of glycans in unfractionated biofluids through the chemical breakdown of glycans into their constituent linkage-specific monosaccharides for detection by GC-MS. Potential applications include early detection of cancer and other glycan-affective disorders.

聚糖节点分析:自下而上的方法，以糖原组学

Synthesized in a non-template-driven process by enzymes called glycosyltransferases, glycans are key players in various significant intra- and ...

Characterizing Electron Transport through Living Biofilms

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under physiologically relevant conditions.1 These measurements are performed on living biofilms in aqueous medium using source and drain electrodes patterned on a glass surface in a specialized configuration referred to as an interdigitated electrode (IDA) array. A biofilm is grown that extends across the gap connecting the source and drain. Potentials are applied to the electrodes (ES and ED) generating a source-drain current (ISD) through the biofilm between the electrodes. The dependency of electrical conductivity on gate potential (the average of the source and drain potentials, EG = [ED + ES]/2) is determined by systematically changing the gate potential and measuring the resulting source-drain current. The dependency of conductivity on gate potential provides mechanistic information about the extracellular electron transport process underlying the electrical conductivity of the specific biofilm under investigation. The electrochemical gating measurement method described here is based directly on that used by M. S. Wrighton2,3 and colleagues and R. W. Murray4,5,6 and colleagues in the 1980&#39;s to investigate thin film conductive polymers.

A protocol for measuring electrical conductivity of living microbial biofilms under physiologically relevant conditions is presented.

通过活生物膜表征电子传输

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under ...

Quantifying X-Ray Fluorescence Data Using MAPS

The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical composition and elemental distribution within a material. Synchrotron-based XRF has become an integral characterization technique for a variety of research topics, particularly due to its non-destructive nature and its high sensitivity. Today, synchrotrons can acquire fluorescence data at spatial resolutions well below a micron, allowing for the evaluation of compositional variations at the nanoscale. Through proper quantification, it is then possible to obtain an in-depth, high-resolution understanding of elemental segregation, stoichiometric relationships, and clustering behavior.
This article explains how to use the MAPS fitting software developed by Argonne National Laboratory for the quantification of full 2-D XRF maps. We use as an example results from a Cu(In,Ga)Se2 solar cell, taken at the Advanced Photon Source beamline 2-ID-D at Argonne National Laboratory. We show the standard procedure for fitting raw data, demonstrate how to evaluate the quality of a fit and present the typical outputs generated by the program. In addition, we discuss in this manuscript certain software limitations and offer suggestions for how to further correct the data to be numerically accurate and representative of spatially resolved, elemental concentrations.

Here, we demonstrate the use of the X-ray fluorescence fitting software, MAPS, created by Argonne National Laboratory for the quantification of fluorescence microscopy data. The quantified data that results is useful for understanding the elemental distribution and stoichiometric ratios within a sample of interest.

利用地图量化 X 射线荧光数据

The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical ...

The Effect of Charging and Discharging Lithium Iron Phosphate-graphite Cells at Different Temperatures on Degradation

The effect of charging and discharging lithium iron phosphate-graphite cells at different temperatures on their degradation is evaluated systematically. The degradation of the cells is assessed by using 10 charging and discharging temperature permutations ranging from -20 &#176;C to 30 &#176;C. This allows an analysis of the effect of charge and discharge temperatures on aging, and their associations. A total of 100 charge/discharge cycles were carried out. Every 25 cycles a reference cycle was performed to assess the reversible and irreversible capacity degradation. A multi-factor analysis of variance was used, and the experimental results were fitted showing: i) a quadratic relationship between the rate of degradation and the temperature of charge, ii) a linear relationship with the temperature of discharge, and iii) a correlation between the temperature of charge and discharge. It was found that the temperature combination for charging at +30 &#176;C and discharging at -5 &#176;C led to the highest rate of degradation. On the other hand, the cycling in a temperature range from -20 &#176;C to 15 &#176;C (with various combinations of temperatures of charge and discharge), led to a much lower degradation. Additionally, when the temperature of charge is 15 &#176;C, it was found that the degradation rate is nondependent on the temperature of discharge.

This article describes the effect of dissimilar charging/discharging temperatures on the degradation of lithium iron phosphate-graphite pouch cells, aiming at simulating close to real case scenarios. In total, 10 temperature combinations are investigated in the range -20 to 30 &#176;C in order to analyze the impact of temperature on degradation.

不同温度下的磷酸铁锂-石墨电池充放电对降解的影响

The effect of charging and discharging lithium iron phosphate-graphite cells at different temperatures on their degradation is evaluated systematically. ...