Department of Chemistry, The Pennsylvania State University, University Park, 16802, USA.
Analyst. 2011 Jun 21;136(12):2564-71. doi: 10.1039/c1an15168a. Epub 2011 May 12.
Differential magnetic catch and release (DMCR) has been used as a method for the purification and separation of magnetic nanoparticles. DMCR separates nanoparticles in the mobile phase by magnetic trapping of magnetic nanoparticles against the wall of an open tubular capillary wrapped between two narrowly spaced electromagnetic poles. Using Au and CoFe(2)O(4) nanoparticles as model systems, the loading capacity of the 250 μm diameter capillary is determined to be ∼130 μg, and is scalable to higher quantities with larger bore capillary. Peak resolution in DMCR is externally controlled by selection of the release time (R(t)) at which the magnetic flux density is removed, however, longer capture times are shown to reduce the capture yield. In addition, the magnetic nanoparticle capture yields are observed to depend on the nanoparticle diameter, mobile phase viscosity and velocity, and applied magnetic flux. Using these optimized parameters, three samples of CoFe(2)O(4) nanoparticles whose diameters are different by less than 10 nm are separated with excellent resolution and capture yield, demonstrating the capability of DMCR for separation and purification of magnetic nanoparticles.
差分式磁捕获和释放（DMCR）已被用作纯化和分离磁性纳米粒子的方法。DMCR 通过将磁性纳米粒子在磁场中捕获并紧贴在两个电磁极之间的开放式管状毛细管的壁上来分离流动相中纳米粒子。使用 Au 和 CoFe(2)O(4)纳米粒子作为模型系统，确定 250 μm 直径毛细管的装载量约为 130 μg，并可通过使用更大内径的毛细管扩展到更高的载量。DMCR 中的峰分辨率通过选择释放时间（R(t)）来外部控制，在该时间，移除磁场强度，但较长的捕获时间会降低捕获效率。此外，观察到磁性纳米粒子的捕获效率取决于纳米粒子的直径、流动相的粘度和速度以及施加的磁场强度。使用这些优化的参数，可以将直径相差不到 10nm 的三个 CoFe(2)O(4)纳米粒子样品分离，分辨率和捕获效率都非常高，这证明了 DMCR 用于磁性纳米粒子的分离和纯化的能力。
