This work was funded by the Swiss National Science Foundation (grant n&#176; 200021-140230) and by the Swiss Federal Office of Public Health (PF and PS). We thank the Swiss Federal Office of Public Health for providing financial support for the open-access publication of this paper.

1.钚示踪准备<ol><li>浦（四）示踪剂的准备<ol><li>从莆原液含有钚用于实验的所需量的适当的等分试样转移到25毫升玻璃烧杯中。 10贝可的239浦同时工作。 </li><li>加入1毫升浓HNO 3，0.6 ml的1M的硫酸氢钠，0.4毫升浓H 2 SO 4。蒸发至干的热板上。热慢慢在200℃在一开始，以避免酸投影。 </li><li>一旦没有液体留在烧杯中，退火残余物在400℃ - 500℃，直至没有白烟发出。冷却并溶于选择用于实验的缓冲器时，残余物为白色。 注意:浦（IV）的以这种方式制备的源可以被干燥储存长达数月12。 </li></ol></li><li>浦（V）示踪剂准备13 <ol><li>浦氧化<ol><li>从浦申通快递转移等分放溶液到塑料20ml液体-闪烁小瓶防漏帽。 10贝可的239浦同时工作。加的0.01M 高锰酸钾 0.01 ml和离开该混合物在黑暗中至少6小时。 </li></ol></li><li>浦（六）提取<ol><li>在提取之前制备的0.5M的thenoyltrifluoroacetone（TTA）在环己烷中的溶液，保护它的光曝光。总是准备该溶液前立即每次实验。 </li><li> 2 ml的0.5M的thenoyltrifluoroacetone（TTA）在环己烷添加到氧化莆溶液2毫升0.1M的CH 3 COONa，在pH 4.7和。包住瓶用铝箔，以保持反应混合物在黑暗中，振摇10分钟。分离含有普（VI）与移液管并转移到一个干净的玻璃小瓶中的有机相。 </li></ol></li><li>浦（六）浦（V）光还原<ol><li>离开含钚（Ⅵ）-TTA复杂的环己烷在室温光2小时的玻璃小瓶。 </li></ol></li><li>浦（V）提取<ol><li>添加到光暴露溶液1毫升0.1M的CH 3 COONa，在pH 4.7和振摇5分钟。除去水相，含有浦（Ⅴ）。确定这个源通过液体闪烁计数取100μl等分的浓度。 注:准备浦（V）紧接自浦在+ V氧化态的长期稳定性每个实验备受质疑的解决方案。 </li></ol></li></ol></li></ol> 2.准备实验中使用的解决方案<ol><li>准备缓冲溶液<ol><li>使MOPS 10mM的溶液（3-（N-吗啉代）丙磺酸）缓冲液。需要200毫升该溶液，并通过逐滴加入0.1M的HCl（用于与普（IV）和pH 5.5的使用为使用浦（V）的pH为6.5）调节到所需的pH值。 </li></ol></li><li>与浦（四）准备实验方案<ol><li>解决方法A <ol><li>溶解普（四）准备在步骤1.1 SE为10mM MOPS veral毫升缓冲溶液在pH 6.5。彻底洗净用相同溶液的烧杯中。 </li><li>使体积到72毫升的10mM MOPS缓冲溶液在pH 6.5。检查pH并重新调整至6.5，用0.1M NaOH洗涤。传输72个毫升该溶液放入一个干净的烧杯中 - 这是（A）的溶液被引入到扩散池的腔A。 </li></ol></li><li>溶液B <ol><li>需要72毫升缓冲在pH 6.5溶液的10mM MOPS;添加的1M 的 Na 2 SO 4 0.75毫升检查pH值，如有必要，再调节至6.5。传输72个毫升该溶液放入干净烧杯 - 这是"B"的解决方案被引入到"B"的扩散池的隔室。 </li></ol></li><li>准备与NOM解决方案<ol><li>称重冻干黄腐或腐殖酸1.4毫克至20ppm的浓度获得和溶解它在"A"溶液containi吴普（IV）。准备进行试验，并允许达到平衡之前，该溶液24小时。 </li></ol></li></ol></li><li>与浦（V）准备实验方案<ol><li>解决方法A <ol><li>溶解在步骤1.2.4 72毫升缓冲在pH 5.5溶液的10mM MOPS得到普（Ⅴ）;加1M的硝酸钠 0.75毫升。检查pH值，并在必要时调整至5.5。转移到一个干净的烧杯中72个毫升上述溶液。准备试验之前立即与普（V）的解决方案。 </li></ol></li><li>溶液B <ol><li>需要72毫升缓冲在pH 5.5溶液的10mM MOPS;加1M的硝酸钠 0.75毫升。检查pH值，并在必要时调整至5.5。转移到一个干净的烧杯中72个毫升上述溶液。 </li></ol></li><li>准备与NOM解决方案<ol><li>称重冻干黄腐或腐殖酸1.4毫克，得到20ppm的浓度和溶解在含有普（V）的溶液。离开24小时解决方案向莆（IV）和浦（V）物种之间达到稳定状态。此前扩散试验进行液相萃取，以确定普（V）的比例如3.4.2节描​​述。 </li></ol></li></ol></li></ol> 3.实验室扩散实验<ol><li>准备聚丙烯酰胺凝胶<ol><li>湿的塑料托盘与电解质的几毫升（例如，10毫硝酸钠3），放置在PAM中凝胶带和扩大均匀地在表面上。将谨慎2.7厘米的尖锐拳打在直径上的凝胶表面。避免滑动冲在凝胶表面。 </li><li>使用本地重点照明，如果有必要，它可以帮助以可视化的透明PAM凝胶。按下冲头，使其紧贴凝胶表面并释放，一旦它被切断。 </li></ol></li><li>扩散池的装配<ol><li> PAM的露盘用镊子放置进沟了在光滑面的方式扩散窗口。转动螺钉，使得总重量澳扩散池的车厢抱在了一起，通过PAM露盘相互连接。 </li><li>马克·A和B的扩散细胞的车厢。组装与凝胶圆盘之前立即每次实验的扩散池;不允许凝胶干燥。 </li></ol></li><li>启动扩散试验<ol><li>慢慢倒入A和B溶液到相应的隔间。确保两个解决方案，以便提供在每个隔室随时等体积倾以相同的速度，否则漫射凝胶可能会损坏。 </li><li>启动计时器一旦解决方案是在细胞中。放置微型电动搅拌机在扩散池。此时的扩散实验被认为是开始。 </li></ol></li><li>以样本在整个扩散实验<ol><li>取同等体积的样品内从A和B室规则的时间间隔同时，为了保持恒定的卷整个experimeNT。 <ol><li>同时在每个室立即采取1.00 ml的样品在实验开始，以确定在A室中的初始莆浓度。 </li><li>使用的实验10分钟的采样时间间隔不加NOM和20分钟到几个中的H与腐植酸的实验。 2.00毫升等份足以用于α-光谱测量提供良好的灵敏度。 </li></ol></li><li>浦（IV）和浦（V）的液相萃取<ol><li>在扩散实验结束时取分开4 ml的来自A和样品的乙隔间成塑料试管与防漏帽。酸化的样品用1毫升的2M HCl中。 </li><li>加入5毫升0.5M的双（2-乙基己基）磷酸（HDEHP）环己烷溶液和搅拌试管剧烈5分钟。离开样品以允许相分离。删除含浦（V）的水相。 </li></ol></li><li>反萃取钚（IV） <ol><li>返回-EX道浦（Ⅳ）从用5毫升5％（NH 4）2 C 2 O 4剩余的有机相。 </li></ol></li></ol></li></ol> 4.样品处理<ol><li>穗样本内标<ol><li>穗样品与示踪物收率进行分析。用1.00毫升的25 MBQ毫升242浦示踪剂-1活性浓度的α-光谱测量激增。 </li></ol></li><li>氧化样品&#39;矩阵<ol><li>蒸发样品至干燥的热板上用2.00的浓HNO 3的。 </li></ol></li></ol>浦5.放射化学分离<ol><li>调整浦氧化状态<ol><li>溶解从点4.2.1干样品在5ml的8M 硝酸 ，在10分钟内加入20毫克的NaNO 2，热样品在70℃。此步骤可调节浦的氧化态为+ IV。 </li></ol></li><li>浦的固相萃取<ol><li>湿的季胺系阴离子交换树脂柱（例如TEVA）用1.5ml的8M 硝酸 。使用与树脂的空调用1.5ml的8M 硝酸 100毫克制成1毫升枪头微列。 </li><li>通过树脂柱，以约1ml min流速经过点5.1.1的溶液-1。冲洗用2ml的8M 硝酸三次，并转移到冲刷树脂柱样品烧杯中。 </li></ol></li><li>洗脱浦<ol><li>用3毫升9 M盐酸洗柱。浦洗脱用3毫升的溶液9 M盐酸/ 0.1M的HI。蒸发在热板上洗脱液。治疗用2ml浓HNO 3，蒸发至干。如果需要的话，直到褐色碘的颜色消失重复。 </li><li>确定样本中钚的浓度用任何有效的方法。 注意:对于本协议的α-法所使用的浓度范围239浦提供了良好的灵敏度。准备源字母spectrometriÇ指望通过电镀不锈钢盘14。算上PIPS探测器（450 平方毫米）的光谱仪的来源。 </li></ol></li></ol>数据6.分析<ol><li>剧情扩散浦与时间的关系<ol><li>剧情浦（活度）的在B室对时间（分钟）积累的活性。正确的扩散实验过程中取出的样品的体积:累积浦（活度）在时间t的活性等于浓度（MBQ毫升-1）样本乘上的溶液（毫升）的容积中确定的在采样的时刻分隔间B（参见实施例的电子表格的- 图2）。 </li><li>要绘制从几个实验用不同浓度的钚同样的图形数据，使用浓度归一室A的初始浦浓度</li></ol></li><li>计算扩散系数<ol><li>计算扩散系数D（cm 2的</su浦物种每个实验10的对&gt; 秒 -1）。用公式（1）: <img alt="式（1）" src="/files/ftp_upload/53188/53188eq1.jpg" /> （1） 其中ΔG是扩散凝胶厚度（厘米），C的初始莆浓度（MBQ毫升-1），S的扩散面积（cm 2），以及A的活性（活度） 在时间t扩散室乙莆物种（秒）。ΔA/Δt为浦的线性情节扩散到B舱与时间的斜率。 </li></ol></li></ol>浦天然淡水7.生物利用度研究<ol><li>准备DGT采样<ol><li>湿的塑料托盘与电解质的几毫升（例如，10毫硝酸钠3），放置在底板（ 见图 3）的DGT取样。必要时可使用局部照明，它可能有助于可视化的透明凝胶。 </li><li> POSITI在将6cm×22厘米CHELEX树脂胶条和扩大均匀地分布在板的表面。放置在树脂凝胶层6厘米×22厘米的PAM漫射凝胶条的顶部和扩大均匀地在表面上。确保凝胶不滑动和定位在一个光滑面的方式。 </li><li>覆盖扩散凝胶层与6厘米×22厘米片的过滤膜。放置DGT采样器的盖框架（ 见图 3）在过滤器膜并关闭装配略微加压的边缘的帧。 </li><li>用锋利的刺血针切割延伸凝胶部分关闭，打开和直至获得光滑板面在必要时重新对准凝胶层。固定用螺丝组装。 </li><li>湿电信局采样与电解质的几毫升（ 如 10毫米硝酸钠 ）。存放在密封的塑料袋多达湿几个星期在4-5℃。 </li></ol></li><li> DGTs在自然水体部署<ol><l我&gt;就拿DGT取样出来的塑料袋。固定DGT采样在保持器上所示的图4。 </li><li>部署DGTs在水体或者它们悬浮在一个结实的绳子或的方式，以提供沿着所述DGT的表面上的恒定切向水流量是安装在稳定的垂直支撑。为了积累莆其浓度足以进行测量部署在淡水为两至三个星期DGT设备。 </li></ol></li><li>检索DGTs治疗<ol><li>检索来自水DGTs。拧开大会，取出过滤膜，并丢弃。取出上层凝胶层（PAM扩散凝胶）并丢弃。 </li><li>转移树脂凝胶放入玻璃烧杯中含20ml的8M 硝酸和穗的样本与一个收率示踪剂进行分析。用1.00毫升0.25活度毫升-1（1.7皮克毫升-1）放射性浓度AMS测量242浦示踪激增。具有良好AGI后tated，留下样品O / N为浦洗脱。 </li></ol></li><li>条件DGT洗脱液<ol><li>过滤从树脂凝胶样品的解决办法;冲洗剩余的凝胶树脂用5ml的8M 硝酸并结合冲刷的样品。加入20毫克的NaNO 2至每个样品中，在10分钟内加热该溶液在70℃。此步骤可调节浦的氧化态为+ IV。 </li></ol></li><li>浦的固相萃取<ol><li>湿用10ml的8M 硝酸季胺系阴离子交换树脂盒。通过与约1ml分钟-1流速交换树脂盒传递点7.4.1的解决方案。冲洗用5毫升的8M 硝酸三倍的样品杯和冲刷转移到交换树脂滤芯。 </li></ol></li><li>洗脱浦<ol><li>用10ml 9 M盐酸洗墨盒。浦洗脱用15毫升的溶液9 M盐酸/ 0.1M的HI。蒸发洗脱物在热板上。治疗用2毫升浓HNO 3，Evaporate至干。必要时重复进行，直到褐色碘的颜色完全消失。 </li><li>重复莆一个放射化学分离超过两次，如果高纯化要求 - 取决于莆检测系统的性能。执行第二和微观列第三分离与交换树脂100毫克空调用1.5ml 8M的HNO 3做1毫升的枪头。 </li><li>确定样本中钚的浓度。使用质谱分析技术来衡量，因为钚的原始环境中的极低水平的239蒲。 注:在这项工作中，使用AMS设备调整为锕系元素的分析，在离子束物理实验室技术的瑞士联邦理工学院苏黎世。 </li></ol></li></ol>数据8.分析<ol><li>计算浓度 （C 电信总局 μBq毫升-1）的生物利用度（不稳定）普SPECIES在散水从浦在部署期间由电信总局累积量。用公式（2）: <img alt="公式（2）" src="/files/ftp_upload/53188/53188eq2.jpg" /> （2） 其中 A是活性钚（μBq）在的粘结相中，ΔG扩散层（凝胶+滤膜）厚度（厘米）中，D莆在PAM凝胶的扩散系数（厘米2秒 -1），S积累扩散面积（cm 2）， 和 T部署（秒）的持续时间。 </li><li>比较莆了 C DGT通过DGTs总莆浓度在大体积的水，以及与其他可用的形态数据确定。 </li></ol> 9.放射化学分离的总浦在散水的测定<ol><li>条件水样<ol><li>从水体研究通过45微米的滤膜过滤泵水变成了PLASTIC收件人。为10至50升用于AMS测量样品工作。在采样点运送到实验室之前取样后立即酸化水至pH 2 HNO 3。 </li></ol></li><li>沉淀普铁的氢氧化物<ol><li>在实验室中引入一个顶部搅拌器到受体。穗与浦产量示踪剂的样品。用1.00毫升0.25活度毫升-1（1.7皮克毫升-1）放射性浓度AMS测量242浦示踪激增。 </li><li>添加氯化铁·6H 2 O取约0.25g每10升的样品。具有搅拌30分钟后，沉淀氢氧化铁用 NH 4 OH在pH值为8。 </li></ol></li><li>浦铁的氢氧化物沉淀二<ol><li>从点9.2.2倒出水样上清液。回收的氢氧化铁沉淀物置于2L的玻璃烧杯中，冲洗收件人用去离子水并结合冲刷与SAMP勒。 </li><li>溶解沉淀物在约100 ml的5 M盐酸，加热至90℃以分解碳酸盐。如果需要的话，当溶液冷却过滤。重新沉淀氢氧化铁用 NH 4 OH在pH值为8。 </li></ol></li><li>条件铁的氢氧化物分析<ol><li>滗析从点9.3.2样品上清液。回收的氢氧化铁沉淀到离心容器中。离心机，弃去上清液。洗用离子交换水的沉淀物。重复2-3次。 </li><li>溶解在10毫升的8M 硝酸的沉淀物，向莆放射化学分离作为章节7.4-7.6如前所述。 </li></ol></li></ol> 10.制备样品的AMS测量<ol><li>沉淀普铁的氢氧化物<ol><li>放射化学分离后，溶解在0.5ml的1M的HCl的最终样品，将样品与一个塑料吸管转移到2.5毫升的玻璃小瓶中。冲洗样品杯TWICË用0.5ml 1 M盐酸，转移冲刷到同一个小瓶。 </li><li>加入0.5毫升2毫克毫升-1的Fe 3+原液提供1毫克的铁。沉淀氢氧化铁加入几滴浓NH 4 OH的。离心，倒出上清液。 </li><li>洗去离子水，离心沉淀，倒出上清液。干在热板上将沉淀在90℃。 </li></ol></li><li>准备目标AMS测量<ol><li>烘烤的氢氧化物从点10.1.3在炉沉淀2-3小时，在650℃。用3-4毫克铌金属粉末，然后按调匀成AMS测量Ti靶标架。 注意:我们测量了样品的紧凑型（0.6 MV）AMS系统"TANDY"在技术的瑞士联邦理工学院（ETH苏黎世）调谐锕系15,16测量。 </li></ol></li></ol>

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The authors have nothing to disclose.

这里所描述的实验中，使用普扩散细胞的DGT的方法提供了在浦氧化还原物种及其与有机分子，胶体粒子和模拟环境系统相互作用的各种研究一个可靠的方法。 DGTs为浦环境测量的进一步应用，将有助于我们的生物利用度的认识，这种放射性核素的水生生态系统的命运。 实验室扩散实验 为了进行成功的扩散实验上莆流动性和关于特定的化学环境中有意义的结论的相互作用，以及定义和可控的条件必须被提供。进行实验之前，莆氧化态的调整是必要的，以简化的数据解释以及模拟莆氧化还原物质的各种生物地球化学的行为。浦物种对灵敏度pH值的变化使得缓冲的解决方案是必须的。应特别注意吸引到扩散池的特性和设置:使用非吸水特氟隆聚合物材料避免吸附在孔壁上，并允许一个健壮防漏组件，防止莆损失从实验期间扩散的解决方案。 初始莆浓度被引入到所述的贮存舱，以及采样间隔和扩散实验期间拍摄各样品的体积依赖于在实验室中可用的分析方法。任何可用的分析方法可用于确定莆浓度从扩散细胞的样品中，但是这种选择紧紧结合莆的取供实验的初始活性。 239莆10贝的建议，在此协议（得到100-140 MBQ毫升-1或〜2×10 -13摩尔毫升-1）足以提供足够的灵敏度为measurem经济需求测试的α-法，一般不会造成特别的问题，为辐射防护规定。浦的初始浓度可以降低，如果其他更敏感，分析技术可用于莆测定（例如，质谱）。采样间隔可被选择为每个扩散实验，这取决于莆初始浓度，并扩散通过PAM凝胶预期速率。尽管这一事实从扩散实验的等分试样不含有放射性核素比普其他，矿物盐和的MOPS缓冲液的存在下可与分析程序干扰，降低了效率和定量分析的精度。因此最好是对这些样品进行莆的化学分离。 扩散细胞为研究扩散在PAM凝胶由于凝胶直接暴露于充分搅拌溶液的最佳方法。漫射博这样的效果undary层（DBL）在凝胶表面被认为是可忽略不计。解的过程中的扩散实验良好的搅拌是必要的，从而允许最小化的DBL影响。在同一时间，应以不破坏凝胶的PAM仔细进行。 普生物利用度的天然淡水的研究 结果通过该协议显示，测量钚DGT设备为研究钚的生物利用度淡水的有效工具产生的。 DGT测量产生自由和不稳定物质时间平均浓度，为生物吸收的两个最重要的形式由活的生物体。另外，普与有机物质相互作用的动力学可以使用不同厚度的凝胶进行调查。对于普NOM物种所需的时间通过凝胶扩散将允许最不稳定的复合物解离。 DGT测量可以补充bÝ超滤技术，其产生莆胶体物质的百分比给定的大小（例如，8 kDa）的上方。浦胶体物质通常被认为非生物可利用的物质，并且是普分数无法衡量使用电信局的一部分。 在这一点上，电信总局设备部署仅在瑞士侏罗山区的岩溶泉的淡水。浦的低环境浓度需要一个长期的部署DGT器件，它可以遇到的潜在缺点。电信局表面的生物结垢表示显著缺点，增加了DBL厚度，从而通过PAM凝胶限制性莆的通量。在海水或高矿化水露DGTs的结合阶段，可以迅速饱和与其他微量金属，歪曲了普积累的数据。浦环境痕量级的测定需要一个全面的放射化学分离和非常敏感的分析方法。 AMS测量在这个协议中施加s为未广泛使用，但可以由其他质谱技术来替换。然而，严格的放射化学分离是必要的，从天然存在的铀消除等压干扰238 UH。 公式2表明，该DGT装置的尺寸是可以被调谐，以增加在给定的部署时间的积累莆量的基本参数。商业胶条仅适用于6厘米×22厘米的最大表面。因此，此时DGT采样的窗口已增加至105厘米2（5厘米×21厘米），使得能够积累莆物种够相对短的部署时间。这样的DGT采样器的组装需要精确和特殊考虑PAM凝胶片性能的同时操作。这是至关重要组装凝胶层成光滑面均匀的"三明治"，以提供一个homoge浦物种从大体积的水通过扩散凝胶neous通量。良好的水流在DGT表面也是一个重要的参数，但它主要是由流动条件在含水层确定。它建议以放置DGT设备为莆测量在约45°向水的流动方向，以提供稳定的水供应和最小化DBL的影响。 如果在水的研究体的温度为在该扩散系数被确定的温度不同的方程2中所用的扩散系数必须予以纠​​正。扩散系数的温度影响由下式给出斯托克斯 - 爱因斯坦方程（方程3）: <img alt="公式3" src="/files/ftp_upload/53188/53188eq3.jpg" /> （3） 其中D 1和D 2是扩散系数（厘米2秒 -1）中，η1和η2是瓦特粘度（毫帕秒）亚特在温度Ť1和分别Ť2（K）。 目前，还没有方法来调查莆形态在原始环境，除了基于，例如，pH值，氧化还原参数热力学计算。这些参数仅用于宏组件，如碳酸盐，铁或锰的阳离子。因此，普形态从这些可测量物质衍生的但不表示一个"真实"测量。在这里，我们认为，在这个文件中提出的扩散薄PAM凝胶膜技术是在浦形态问题的解决迈出的重要一步，因为它允许在测量现场自由和不稳定物质，可能的话，证明钚酰种。虽然环境浦的淡水只有少数DGT测量已开展至今，得到的结果是令人鼓舞的DGT技术浦形态和生物利用度研究中的进一步应用。在富含有机质的水域DGTs的部署将有可能产生在NOM分子的存在对浦的移动性和互动的重要信息。有趣的结果应在污染海洋环境，比如周围的塞拉菲尔德核后处理厂的近海和受损的福岛第一核电站电信局测量，可以预期的。

钚是一种人工放射性核素在环境中存在如下原子弹试验和核事故对全球沉降的结果。钚的氧化还原化学反应有其在环境水生系统1迁移和生物地球化学循环具有重要意义。钚具有复杂的化学和可以在四个氧化态（III，IV，V，VI）同时存在。因此，钚在自然水域的氧化还原物质的分布是，以局部化学环境2,3-极为敏感。钚的氧化态也取决于源的来源 - 这种说法是最相关的污染环境和处理场所处置。减少钚种（+ III和IV +）的主要是发现在缺氧的环境和全球后果起源和库存废污水，而高氧化态（+ V和+六）可以在其他锕系元素的衰变产物发现而在好氧环境4。 流动性和钚的环境行为可以预测到从氧化还原形态某种程度。钚在+Ⅲ和+ IV氧化态存在主要在固相和增加容量能够吸附到无机胶体和天然存在的有机物质（NOM）的分子。钚在+Ⅲ和+ IV氧化态被认为是少的移动。钚（+ V和+ VI + V是最有可能的）5更多可溶性氧化形式可能会导致更高的生物传递到水生生物，由于较高的流动性。然而，在NOM的存在，特别是腐殖酸，普（V）正在减少17，移动分区几个数量级，有利于沉淀。尽管普（V）至普的减少率（IV）的幅度4〜5级比逆反应速度更快，浦（四）在氧化条件马再活化另外，Y发生1。修订与浦（Ⅳ），进行自然氧化条件对矿物沉积物最近的实验数据表明，可溶性莆在水相中的浓度随时间增加1.6。作者浦（IV）的氧化吸附和形成更多的可溶普（V）和普（六）种解释。浦氧化（IV），也可能是由于自然遇到的锰氧化物的7出现。这些意见是对的生物利用度建模和废物处置和污染场地环境风险评估很重要。 研究生物利用度和钚的形态是在实验室和现场条件下一项艰巨的任务。低环境浓度，氧化还原物质的可变性，并与天然胶体的相互作用使得难以模拟钚的生物地球化学行为。在薄膜（DGT）扩散梯度的技术的基础上的自由和不稳定污染物种类通过聚丙烯酰胺（PAM）的凝胶中的扩散被广泛用于微量元素8的环境测量。甲DGT取样表示由一个粘结相的三层装置（为广大的微量金属是包含在PAM凝胶CHELEX树脂），扩散凝胶层（不同厚度的PAM凝胶）和过滤膜保护凝胶和拿着组装在一起。聚丙烯酰胺凝胶的薄膜，由水85％，使自由和不稳定复杂物种比钚势必大型NOM分子或天然胶体粒子扩散更迅速。甲设置旨在研究在实验室条件下的PAM薄凝胶薄膜钚扩散被称为扩散单元9。 甲扩散池是在两个分开的隔室是通过一个给定的表面的开口相互连接的两隔室容器中。开场， 即两个腔室C之间的窗口ontains给定厚度的凝胶扩散的盘。我们构建了特氟隆细胞用两份100ml隔间和圆形扩散窗口1.7厘米的直径。一个车厢是可移动的，便于组装。 A 0.5厘米宽的沟刻扩散窗口周围的固定隔间用来放置扩散露盘。凹槽深度应该是类似的PAM凝胶厚度供使用。我们选择了0.39毫米PAM凝胶的工作，因此槽深度在我们的扩散池为0.39毫米。扩散池的详细图象是在图1。 当最初包含钚的溶液放入一个隔室（A）中，漫射莆物种将建立的浓度梯度在凝胶中，并会开始积累在第二隔室（B）中，最初包含相同的化学组成的不普溶液。浦物种在隔室A的初始浓度被定义使得其remai纳秒恒定或变化很小（1％-2％最多）整个扩散实验。绘制扩散莆的量与时间的关系提供了一种分析莆物种盛行于不同模拟的环境条件下的流动性的装置。扩散在薄膜提供了在浦流动性和形态研究一个有价值的替代，可以在野外条件下10成功应用。人们可通过一个被动采样，与PAM扩散凝胶和CHELEX树脂作为结合相，其用于累积扩散莆物种制更换扩散池中。这样的取样器可以暴露在野外条件-浦在树脂积累的量将指示形态和Pu的相应的应用环境10中的生物利用度。 在这项工作中，我们使用了扩散室与NOM在实验室条件下，调查浦（IV）和普（V）的物种和它们的相互作用的流动性。福rthermore，我们采用105 平方厘米的表面的大型被动DGT采样研究普的生物利用度的岩溶泉瑞士侏罗山脉（Venoge河），其中浦的显著的成分是水生苔藓细胞内部分一个以前的工作11。由于钚存在于原始的环境的非常低的水平，基于加速器的质谱（AMS）的可在苏黎世技术被用于测量钚的同位素。

<table><tbody><tr><td>&lt;sup&gt;239&lt;/sup&gt;Pu tracer</td><td>CEA</td><td></td><td>Source PU239-ELSC10</td></tr><tr><td>&lt;sup&gt;242&lt;/sup&gt;Pu tracer</td><td>LNSIRR</td><td></td><td>Source Pu242 N&amp;deg; 790 from Laboratory for National Standards of Ionizing Radiation of Russia</td></tr><tr><td>25 ml Beakers</td><td></td><td></td><td></td></tr><tr><td>Pipette</td><td>Socorex</td><td></td><td></td></tr><tr><td>Disposable plastic pipettes</td><td>Semadeni</td><td></td><td></td></tr><tr><td>20 ml Plastic scintillation vial</td><td>Semadeni</td><td></td><td></td></tr><tr><td>Aluminium foil</td><td></td><td></td><td></td></tr><tr><td>Hot plate</td><td></td><td></td><td></td></tr><tr><td>Tweezers</td><td></td><td></td><td></td></tr><tr><td>Actinide exchange resin - TEVA - B</td><td>Triskem</td><td>TE-B50-A</td><td></td></tr><tr><td>Actinide exchange resin - TEVA - R cartridges</td><td>Triskem</td><td>TE-R10-S</td><td></td></tr><tr><td>1 ml Pipette tips</td><td>Socorex</td><td></td><td></td></tr><tr><td>PAM gel strip 6&amp;times;21 cm</td><td>DGT Research Ltd</td><td></td><td>0.39 mm and 0.78 mm thickness / www.dgtresearch.com</td></tr><tr><td>Chelex gel strip 6&amp;times;21 cm</td><td>DGT Research Ltd</td><td></td><td>0.40 mm thickness / www.dgtresearch.com</td></tr><tr><td>Diffusion cell</td><td></td><td></td><td>Fabricated / in-house workshop</td></tr><tr><td>&amp;Oslash; 27 mm Punch</td><td></td><td></td><td>Fabricated / in-house workshop</td></tr><tr><td>Plastic tray</td><td></td><td></td><td></td></tr><tr><td>DGT set-up</td><td></td><td></td><td>Fabricated / in-house workshop</td></tr><tr><td>Membrane filter</td><td>PALL Corporation</td><td></td><td>HT-450 Tuffryn Polysulfone Membrane Disc Filter 0.45 &amp;mu;m / 145 &amp;mu;m thickness</td></tr><tr><td>Nitric acid&amp;nbsp;</td><td>Carlo Erba</td><td>408025</td><td></td></tr><tr><td>Sulfuric acid</td><td>Sigma-Aldrich</td><td>84720</td><td></td></tr><tr><td>Hydrocloric acid</td><td>Carlo Erba</td><td>403981</td><td></td></tr><tr><td>Hydriodic acid</td><td>Merck</td><td>100341</td><td></td></tr><tr><td>Potassium permanganate</td><td>Merck</td><td>105082</td><td></td></tr><tr><td>Sodium hydrogen sulfate</td><td>Merck</td><td>106352</td><td></td></tr><tr><td>Sodium sulfate</td><td>Merck</td><td>106647</td><td></td></tr><tr><td>Sodium nitrate</td><td>Sigma-Aldrich</td><td>31440</td><td></td></tr><tr><td>Sodium nitrite</td><td>Fluka</td><td>71759</td><td></td></tr><tr><td>Sodium acetate</td><td>Merck</td><td>106281</td><td></td></tr><tr><td>Ammonium oxalate</td><td>Fluka</td><td>9900</td><td></td></tr><tr><td>Bis-(2-ethyl hexyl) phosphoric acid (HDEHP)</td><td>Merck</td><td>177092</td><td></td></tr><tr><td>2-thenoyltrifluoroacetone (TTA)</td><td>Fluka</td><td>88300</td><td></td></tr><tr><td>MOPS buffer</td><td>Sigma-Aldrich</td><td>M9381</td><td>MOPS sodium salt</td></tr><tr><td>Cyclohexane</td><td>Carlo Erba</td><td></td><td></td></tr><tr><td>Humic acid</td><td></td><td></td><td>Extracted from an organic-rich soil of an Alpine Valley, freeze-dried, MW 5-40 kDa</td></tr><tr><td>NH&lt;sub&gt;4&lt;/sub&gt;OH</td><td>Carlo Erba</td><td>419943</td><td></td></tr><tr><td>FeCl&lt;sub&gt;3&lt;/sub&gt;&amp;middot;H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Sigma-Aldrich</td><td>44944</td><td></td></tr></tbody></table>

speciation and bioavailability measurements of environmental plutonium using diffusion in thin films

钚在水生生态系统的生物吸收是特别关注的，因为它是一个α粒子发射体长半衰期这有可能导致生物和人类的接触。在薄膜技术的扩散梯度在这里介绍了现场测量浦生物利用度和物种形成。对于实验室实验用Pu和新开发的协议构造的扩散池中使得能够模拟莆的各种化学组合物的模型的解决方案的环境行为。的氧化态为普（IV）和浦（五）在本协议中所描述的调整是为了研究钚的复杂的氧化还原化学环境中是必不可少的。该技术的校准，并在实验室的实验中获得的结果使得能够开发一种特定DGT设备用于原位莆在淡水测量。基于加速器的质谱测量浦积累通过在岩溶泉DGTs允许确定矿物淡水环境浦的生物利用度。该协议使用DGT装置浦测量中的应用有着巨大的潜力，以改善我们的形态和浦的水生生态系统的生物传递的理解。

扩散实验 标绘239莆扩散到扩散池相对于时间的乙隔室的活动使239莆物种通过PAM凝胶扩散的通量的可视化表示。从这些曲线根据等式1提供比较不同的239莆氧化还原物质中的各种化学环境（图2）的移动性的附加 ​​装置的扩散系数计算出来的。 图5示出了扩散实验浦（IV）和钚（Ⅳ）-PU （V）的混合物种，分别在MOPS缓冲液，并在20 ppm的HA的存在。这些地块的比较表明，莆（V）的比莆显著多个移动（IV）。这是特别有效的普（IV）和普（V）时的HA（MW 5-40 kDa的在我们的实验中，其特征在的SI由Cusnir 等人）10加入作为络合的分子。浦（V）源SOLUT离子制备按照本文所描述的协议主要含有普（V）的物种。液相萃取HDEHP在扩散实验在缓冲溶液中的MOPS的末端发现浦（V）的80％±10％。该提取的化学产率为80％。在20 ppm的HA的存在具有普（五）解决方案在24小时和普（V）部分在该模型溶液35％±10％的平衡。 作者:浦生物利用度的天然淡水 在我们的实验室建造了几个DGT装置已成功暴露两到三个星期在瑞士侏罗山区的岩溶泉时期。这是一个矿泉水与水的在6.5-7.5范围内的pH值，电导率高于400μS-1和氧饱和。这些实验表明凝胶组件良好的适用性和耐用性的没有一丝生物污染的，也可能是因为的t他的弹簧（7℃）的低温。在部署后取出DGTs被保存完好，具有凝胶层完好，保存最初的形式和外观。浦由DGTs蓄积的AMS分析。 AMS提供相当大的优势比其他分析技术:它是高度敏感的（低至亚FG水平），并且要求比的α-法或ICP-MS技术低得多的初始样品量。此外，分子等压干扰，如氢化铀（238 UH），或其它分子的AMS测量期间被有效地抑制，并且不与239莆检测干扰。对于一些技术原因（最可能是与普239中的污染化学分离），我们不能够使用239普的数据DGTs在该领域的第一个应用程序。尽管如此，240浦结果是公正的。因此，我们计算从测得的239蒲含量&lt;SUP&gt; 240浦，以0.18为240蒲/ 239浦原子比为余波钚。结果总结在表1中。 散装水样测得的239蒲浓度类似于前面这个含水层（1-7μBqL-1）11日报道的浓度。此外，从DGT测量计算239莆浓度测量的不确定性范围内类似。因为DGTs积累唯一的自由和不稳定莆物种，可以估算在此水生物利用莆的分数。 表 1中的数据表明，所有的239种莆存在于大体积的水被发现在生物可利用的形式。这是一个有趣的结果在先前的发现11，其揭示的239 + 240莆的主要积累在水生苔藓的胞内部分中的弹簧生长相比的光<suP&gt; 241分及90老作者11表明莆在这个天然含水层的迁移率提高了，是由于地层的可溶性碳酸盐莆复杂，可能作为一个普（V）的钚酰形式，类似于天然存在的双氧铀碳酸复杂。在Venoge春天的水是硬水，具有较高的碳酸盐浓度和极低的天然有机物含量（约1ppm）。 <img alt="图1" src="/files/ftp_upload/53188/53188fig1.jpg" /> 通过PAM凝胶用于实验的普扩散图1扩散槽的槽厚度内径0.5cm槽深0.39毫米。 <a href="https://www.jove.com/files/ftp_upload/53188/53188fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/53188/53188fig2.jpg" /> 图2. Snapsh用于扩散系数计算的Excel工作表的加时赛。 <a href="https://www.jove.com/files/ftp_upload/53188/53188fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/53188/53188fig3.jpg" /> 图3.大面积DGT装置对环境浦形态测量 DGT装置的部件-底板和盖框架-显示在左边，在右边的船员孔装配<a href="https://www.jove.com/files/ftp_upload/53188/53188fig3large.jpg" target="_blank">请点击此处查看大图这个数字。</a> <img alt="图4" src="/files/ftp_upload/53188/53188fig4.jpg" /> 固定在保持器图4 DGT采样装置（左）暴露在Venoge SPRING（右）的浦生物利用度的测量。 <a href="https://www.jove.com/files/ftp_upload/53188/53188fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/53188/53188fig5.jpg" /> 图5.图解239浦扩散到在不同的化学环境的扩散池的乙隔室。实验数据点，给出了239莆（Ⅳ）和239浦（Ⅴ），分别在MOPS缓冲液以及用于239莆（四） -普239（V）混种（35％的浦（V±10％））的HA的存在。示出为239莆（Ⅳ）-HA线路已使用的0.50×10 -6厘米2秒的扩散系数-1先前10确定了计算。由式（1）计算的扩散系数:普（四）在MOPS缓冲- 2.29×10 -6厘米2秒 -1，浦（V）的MOPS缓冲- 3.50×10 -6厘米2秒 -1，浦（IV） -普（V）与HA - 0.92×10 -6厘米2秒 -1。从上至下:浦（V）的MOPS缓冲液（红色空心圆圈），浦（四）在MOPS缓冲液（蓝色空心三角形），浦（IV） - 普（V）在20 ppm的HA的存在（绿色空心方块），浦（四）在20ppm以下HA（棕色钻石开放的存在）。 <a href="https://www.jove.com/files/ftp_upload/53188/53188fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="0"><tbody><tr><td> 样本类型 </td><td> 测量次数 </td><td> 239浦浓度，μBqL -1 </td></tr><tr><td>散水</td><td> 2 </td><td> 1.9±0.55 </td></tr><tr><td> DGT0.39毫米</td><td> 2 </tD&gt; <td> 1.74±0.9 </td></tr><tr><td> DGT0.78毫米</td><td> 1 </td><td> 1.79±0.9 </td></tr></tbody></table> 239浦测量由AMS的散水和DGT采样。普239在散水表1代表性的成果被共沉淀，从20升的水，氢氧化铁，提取的锕系元素特有的交换树脂和AMS测239浦浓度DGT测量使用公式2和扩散系数计算浦（IV）。不确定性对于 k = 2; U（95）。

Watch this Scientific Journal Video about Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films at JoVE.com

利用薄膜扩散测量环境钚的形态和生物利用度生物学 |视频

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

在薄膜扩散梯度（DGT）的技术提出了钚形态研究。这个协议描述扩散实验探测浦（IV）和普（Ⅴ）中的有机物存在下的行为。部署在岩溶泉DGTs让普的生物利用度的评估。

环境钚的薄膜弥散形态和生物利用度测量

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

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11.3K 次观看.  Lausanne University Hospital. 在薄膜扩散梯度（DGT）的技术提出了钚形态研究。这个协议描述扩散实验探测浦（IV）和普（Ⅴ）中的有机物存在下的行为。部署在岩溶泉DGTs让普的生物利用度的评估。 

视频: Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. Radioisotope tracing is a major technique used to measure such fluxes, both within plants, and between plants and their environments. Flux data obtained with radiotracer protocols can help elucidate the capacity, mechanism, regulation, and energetics of transport systems for specific mineral nutrients or toxicants, and can provide insight into compartmentation and turnover rates of subcellular mineral and metabolite pools. Here, we describe two major radioisotope protocols used in plant biology: direct influx (DI) and compartmental analysis by tracer efflux (CATE). We focus on flux measurement of potassium (K+) as a nutrient, and ammonia/ammonium (NH3/NH4+) as a toxicant, in intact seedlings of the model species barley (Hordeum vulgare L.). These protocols can be readily adapted to other experimental systems (e.g., different species, excised plant material, and other nutrients/toxicants). Advantages and limitations of these protocols are discussed.

In planta measurement of nutrient and toxicant fluxes is essential to the study of plant nutrition and toxicity. Here, we cover radiotracer protocols for influx and efflux determination in intact plant roots, using potassium (K+) and ammonia/ammonium (NH3/NH4+) fluxes as examples. Advantages and limitations of such techniques are discussed.

植物与放射性示踪剂测量矿质营养和毒物的通量

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. ...

科研

环境科学

Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects.

Acoustic cavitation in liquids submitted to power ultrasound creates transient extreme conditions inside the collapsing bubbles, which are the origin of unusual chemical reactivity and light emission, known as sonoluminescence. In the presence of noble gases, nonequilibrium plasma is formed. The "hot" particles and the photons generated by collapsing bubbles are able to excite species in solution.

活化分子，离子和固体颗粒与声空化

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic ...

化学

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic&#160;however; this method could have a broader use assessing CuO-NP treatment in more neutral waters.

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

Production bleed water (PBW) was treated with cupric oxide nanoparticles (CuO-NPs) and cellular toxicity was assessed in cultured human cells. The goal of this protocol was to integrate the native environmental sample into a cell culture format assessing the changes in toxicity due to CuO-NP treatment.

去除微量元素的氧化铜纳米粉体制备铀<em&gt;原位</em&gt;恢复泌水及其对细胞活力的影响

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted ...

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging

A method is demonstrated to monitor macroscopic translational diffusion using electron paramagnetic resonance (EPR) imaging. A host-guest system with nitroxide spin probe 3-(2-Iodoacetamido)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (IPSL) as a guest inside the periodic mesoporous organosilica (PMO) aerogel UKON1-GEL as a host and ethanol as a solvent is used as an example to describe the protocol. Data is shown from a previous publication, where the protocol has been applied to both IPSL and Tris(8-carboxy-2,2,6,6-perdeutero-tetramethyl-benzo[1,2-d:4,5-d&#8242;]bis(1,3)dithiole) methyl (Trityl) as guest molecules and UKON1-GEL and SILICA-GEL as host systems. 
A method is shown to prepare aerogel samples that cannot be synthesized directly in the sample tube for measurement due to a size change during synthesis. The aerogel is attached to sample tubes using heat shrink tubing and a pressure cooker to reach the necessary temperature without evaporating the solvent in the process. The method does not assume a clearly defined initial distribution of guest molecules at the start of the measurement. Instead, it requires a reservoir on top of the aerogel and experimentally determines the influx rate during data analysis.
The diffusion is monitored continually over a period of 20 hr by recording the 1d spin density profile within the sample. The spectrometer settings for the imaging experiment are described quantitatively. Data analysis software is provided to take the resonator sensitivity profile into account and to numerically solve the diffusion equation. The software determines the macroscopic translational diffusion coefficient by least square minimization of the difference between the experiment and the numerical solution of the diffusion equation.

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging

A protocol for the in situ monitoring of the diffusion of guest molecules in porous media using electron paramagnetic resonance (EPR) imaging is presented.

在多孔介质中使用电子顺磁共振成像客体分子扩散的原位监测

A method is demonstrated to monitor macroscopic translational diffusion using electron paramagnetic resonance (EPR) imaging. A host-guest system with ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

原位金属氧化物纳米粒子的核探针检测与单细胞定量研究

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Atom Probe Tomography Analysis of Exsolved Mineral Phases

Element diffusion rates and temperature/pressure control a range of fundamental volcanic and metamorphic processes. Such processes are often recorded in lamellae exsolved from host mineral phases. Thus, the analysis of the orientation, size, morphology, composition and spacing of exsolution lamellae is an area of active research in the geosciences. The conventional study of these lamellae has been conducted by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and more recently with focused ion beam (FIB)-based nanotomography, yet with limited chemical information. Here, we explore the use of atom probe tomography (APT) for the nanoscale analysis of ilmenite exsolution lamellae in igneous titanomagnetite from ash deposits erupted from the active Soufri&#232;re Hills Volcano (Montserrat, British West Indies). APT allows the precise calculation of interlamellar spacings (14&#8211;29 &#177; 2 nm) and reveals smooth diffusion profiles with no sharp phase boundaries during the exchange of Fe and Ti/O between the exsolved lamellae and the host crystal. Our results suggest that this novel approach permits nanoscale measurements of lamellae composition and interlamellar spacing that may provide a means to estimate the lava dome temperatures necessary to model extrusion rates and lava dome failure, both of which play a key role in volcanic hazard mitigation efforts.

Analysis of the morphology, composition, and spacing of exsolution lamellae can provide essential information to understand geological processes related to volcanism and metamorphism. We present a novel application of APT for the characterization of such lamellae and compare this approach to the conventional use of electron microscopy and FIB-based nanotomography.

原子探针断层扫描分析的解脱矿物相

Element diffusion rates and temperature/pressure control a range of fundamental volcanic and metamorphic processes. Such processes are often recorded in ...

Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil

We describe a method for two-dimensional (2D) visualization and quantification of the distribution of labile (i.e., reversibly adsorbed) inorganic nutrient (e.g., P, Fe, Mn) and contaminant (e.g., As, Cd, Pb) solute species in the soil adjacent to plant roots (the &#8216;rhizosphere&#8217;) at sub-millimeter (~100 &#181;m) spatial resolution. The method combines sink-based solute sampling by the diffusive gradients in thin films (DGT) technique with spatially resolved chemical analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The DGT technique is based on thin hydrogels with homogeneously distributed analyte-selective binding phases. The variety of available binding phases allows for the preparation of different DGT gel types following simple gel fabrication procedures. For DGT gel deployment in the rhizosphere, plants are grown in flat, transparent growth containers (rhizotrons), which enable minimal invasive access to a soil-grown root system. After a pre-growth period, DGT gels are applied to selected regions of interest for in situ solute sampling in the rhizosphere. Afterwards, DGT gels are retrieved and prepared for subsequent chemical analysis of the bound solutes using LA-ICP-MS line-scan imaging. Application of internal normalization using 13C and external calibration using matrix-matched gel standards further allows for the quantification of the 2D solute fluxes. This method is unique in its capability to generate quantitative, sub-mm scale 2D images of multi-element solute fluxes in soil-plant environments, exceeding the achievable spatial resolution of other methods for measuring solute gradients in the rhizosphere substantially. We present the application and evaluation of the method for imaging multiple cationic and anionic solute species in the rhizosphere of terrestrial plants and highlight the possibility of combining this method with complementary solute imaging techniques.

This protocol presents a workflow for sub-mm 2D visualization of multiple labile inorganic nutrient and contaminant solute species using diffusive gradients in thin films (DGT) combined with mass spectrometry imaging. Solute sampling and high-resolution chemical analysis are described in detail for quantitative mapping of solutes in the rhizosphere of terrestrial plants.

土壤中实验室、无机植物养分和污染物的二维可视化和量化

We describe a method for two-dimensional (2D) visualization and quantification of the distribution of labile (i.e., reversibly adsorbed) inorganic ...

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow injection analysis, has been developed. The concentrations of radioactive strontium were determined by flow scintillation counting, allowing for on-line and also on-site determination. The proposed system can determine radioactive strontium at industrial relevant levels without further modification using overall analysis time of less than 10 min per aqueous sample. The limit of the detection is 320 fg&#183;g-1 (1.7 Bq/g).

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

Here, we present the portable autoRAD platform for quick radiometric separation and determination of 90Sr, an important fission product highly pertinent to nuclear waste.

Ppq 级实验室系统中的自动90Sr 分离和预富集

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow ...

Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides

The age of a submarine hydrothermal sulfide is a significant index for estimating the size of hydrothermal ore deposits. Uranium and thorium isotopes in the samples can be separated for 230Th-U dating. This article presents a method to purify and separate U and Th isotopes in submarine hydrothermal sulfide samples. Following this technique, the separated U and Th fractions can meet measuring requirements by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The age of the hydrothermal sulfide sample can be calculated by measuring the present-day activity ratios of 230Th/238U and 234U/238U. A super clean room is necessary for this experiment. Cleaned regents and supplies are used to reduce the contamination during the sample processes. Balance, hotplate, and centrifuge are also used. The sulfide sample is powdered for analysis and less than 0.2 g sample is used. Briefly, the sample is weighed, dissolved, added to 229Th-233U-236U double spike solution, Fe co-precipitated, and separated on an anion-exchange resin extraction column. Approximately 50 ng U is consumed for 230Th-U dating of sulfides sample by MC-ICPMS.

Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides

The protocol describes a method to purify and separate the U and Th nuclide in submarine hydrothermal sulfide sample with Fe co-precipitation and extraction chromatography for 230Th-U disequilibrium dating.

海底热液硫化物230Th-U测定铀和铀的分离

The age of a submarine hydrothermal sulfide is a significant index for estimating the size of hydrothermal ore deposits. Uranium and thorium isotopes in ...

Quantification of Metal Leaching in Immobilized Metal Affinity Chromatography

Contamination of enzymes with metals leached from immobilized metal affinity chromatography (IMAC) columns poses a major concern for enzymologists, as many of the common di-and trivalent cations used in IMAC resins have an inhibitory effect on enzymes. However, the extent of metal leaching and the impact of various eluting and reducing reagents are poorly understood in large part due to the absence of simple and practical transition metal quantification protocols that use equipment typically available in biochemistry labs. To address this problem, we have developed a protocol to quickly quantify the amount of metal contamination in samples prepared using IMAC as a purification step. The method uses hydroxynaphthol blue (HNB) as a colorimetric indicator for metal cation content in a sample solution and UV-Vis spectroscopy as a means to quantify the amount of metal present, into the nanomolar range, based on the change in the HNB spectrum at 647 nm. While metal content in a solution has historically been determined using atomic absorption spectroscopy or inductively coupled plasma techniques, these methods require specialized equipment and training outside the scope of a typical biochemistry laboratory. The method proposed here provides a simple and fast way for biochemists to determine the metal content of samples using existing equipment and knowledge without sacrificing accuracy.

We present an assay for easy quantification of metals introduced to samples prepared using immobilized metal affinity chromatography. The method uses hydroxynaphthol blue as the colorimetric metal indicator and a UV-Vis spectrophotometer as the detector.

金属浸出在固定金属亲和力色谱中的定量

Contamination of enzymes with metals leached from immobilized metal affinity chromatography (IMAC) columns poses a major concern for enzymologists, as ...

环境钚的薄膜弥散形态和生物利用度测量

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