Development of Quadrupole Magnetic Field-Flow Fractionation: Application to Characterization of Magnetic Colloids and Microparticles

四极磁流分馏技术的发展及其在磁性胶体和微粒表征中的应用本研究的主要目的是将磁场分馏技术发展成为根据磁性胶体的顺磁性成分含量来表征磁性胶体的有力工具。各种FFF技术都是基于洗脱的分离方法，其中胶体材料的延迟程度取决于胶体颗粒与外加电场的相互作用的强度。四极磁场是径向对称的，并适合环形FFF通道几何结构。这种几何构型已经被用于使用免疫特异性磁性胶体标记的生物细胞分选。提出了一种新颖的螺旋通道几何形状，它比简单的环形通道具有几个优点。它简化了入口和出口的几何形状，它将抵消环形圆周周围磁场强度变化的影响，并将增加给定四极磁铁的分离长度。正在致力于优化渠道几何形状和运行条件。载体溶液化学的重要性不可低估，因为必须避免磁化颗粒的聚集或链条。四极磁FFF提供了根据胶体材料在磁化过程中的分布来表征其特性的独特可能性。其他技术只能产生磁化强度的整体或平均值。分销信息对这些材料的制造商来说将是无价的。四极电磁铁的加入将扩大该仪器的适用性。磁场强度可以调整，以适应样品的磁性。利用磁场强度的程序化衰减，该仪器将能够表征磁化强度随颗粒变化很大的磁性多分散颗粒样品。该方法可用于微粒和胶体的表征。它还将有助于通过对颗粒表面进行功能化来促进选择性吸附来分离蛋白质。

Development of Quadrupole Magnetic Field-Flow Fractionation: Application to Characterization of Magnetic Colloids and Microparticles.The main objective of the proposed work is to develop magnetic field-flow fractionation (MgFFF) into a powerful tool for characterizing magnetic colloids in terms of their paramagnetic component content. The various FFF techniques are elution-based separation methods in which the degree of retardation of a colloidal material depends on the strength of interaction of the colloid particles with the applied field. The quadrupole magnetic field is radially symmetrical and lends itself to an annular FFF channel geometry. Such a geometry has already been exploited for biological cell sorting using immunospecific magnetic colloid labels. A novel, helical channel geometry is proposed that will have several advantages over a simple annular channel. It has simplified inlet and outlet geometry, it will nullify the effects of varying field strength around the annular circumference, and it will have increased separation length for a given quadrupole magnet. Effort is being devoted to optimizing the channel geometry and operating conditions. The importance of carrier solution chemistry cannot be underestimated because aggregation or chaining of magnetized particles must be avoided. Quadrupole magnetic FFF offers the unique possibility of characterizing colloidal material in terms of its distribution in magnetization. Other techniques yield only a bulk, or mean value for the magnetization. Distribution information would be invaluable to the manufacturers of these materials. The inclusion of a quadrupole electromagnet will broaden the applicability of the instrument. The field strength can be adjusted to suit the magnetic properties of the sample. Using programmed decay of field strength, the instrument will be capable of characterizing magnetically polydisperse particulate samples in which magnetization varies widely from particle to particle. The method will be useful for characterizing microparticles and colloids. It will also lend itself to separation of proteins by functionalizing the surface of the particles to promote selective adsorption.