Pacific Northwest National Laboratory, Richland, Washington, USA.
Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, USA.
Electrophoresis. 2019 Sep;40(18-19):2531-2540. doi: 10.1002/elps.201900027. Epub 2019 Jun 28.
Elemental analysis of rare earth elements is essential in a variety of fields including environmental monitoring and nuclear safeguards; however, current techniques are often labor intensive, time consuming, and/or costly to perform. The difficulty arises in preparing samples, which requires separating the chemically and physically similar lanthanides. However, by transitioning these separations to the microscale, the speed, cost, and simplicity of sample preparation can be drastically improved. Here, all fourteen non-radioactive lanthanides (lanthanum through lutetium minus promethium) are separated by ITP for the first time in a serpentine fused-silica microchannel (70 µm wide × 70 µm tall × 33 cm long) in <10 min at voltages ≤8 kV with limits of detection on the order of picomoles. This time includes the 2 min electrokinetic injection time at 2 kV to load sample into the microchannel. The final leading electrolyte consisted of 10 mM ammonium acetate, 7 mM α-hydroxyisobutyric acid, 1% polyvinylpyrrolidone, and the final terminating electrolyte consisted of 10 mM acetic acid, 7 mM α-hydroxyisobutyric acid, and 1% polyvinylpyrrolidone. Electrophoretic electrodes are embedded in the microchip reservoirs so that voltages can be quickly applied and switched during operation. The limits of detection are quantified using a commercial capacitively coupled contactless conductivity detector (C D) to calculate ITP zone lengths in combination with ITP theory. Optimization of experimental procedures and reproducibility based on statistical analysis of subsequent experimental results are addressed. Percent error values in band length and conductivity are ≤8.1 and 0.37%, respectively.
稀土元素的元素分析在环境监测和核保障等多个领域都是至关重要的；然而，目前的技术通常是劳动密集型的，耗时且/或昂贵。难点在于样品的制备，这需要分离化学和物理性质相似的镧系元素。然而，通过将这些分离转化为微尺度，可以极大地提高样品制备的速度、成本和简单性。在这里，首次在蛇形熔融硅微通道（70 µm 宽×70 µm 高×33 cm 长）中通过 ITP 分离所有 14 种非放射性镧系元素（镧至镥，钷除外），在 <10 分钟内以 ≤8 kV 的电压完成，检测限为皮摩尔级。这一时间包括在 2 kV 下以 2 分钟的电动进样时间将样品加载到微通道中。最终的先导电解质由 10 mM 乙酸铵、7 mM α-羟基异丁酸、1%聚乙烯吡咯烷酮组成，最终的终止电解质由 10 mM 乙酸、7 mM α-羟基异丁酸和 1%聚乙烯吡咯烷酮组成。电泳电极嵌入微芯片储液器中，以便在操作过程中快速施加和切换电压。使用商业电容耦合非接触式电导检测器（C D）来量化检测限，结合 ITP 理论计算 ITP 区长度。根据后续实验结果的统计分析，讨论了实验程序的优化和重现性。带宽和电导率的百分比误差分别为 ≤8.1%和 0.37%。
