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

四极磁场流分级的发展：应用于磁性胶体和微粒的表征。拟议的工作的主要目标是发展磁场流分级（MgFFF）成为一个强大的工具，用于表征磁性胶体的顺磁成分含量。 各种FFF技术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所施加的场的相互作用的强度。 四极磁场是径向对称的，并且适合于环形FFF通道几何形状。 这种几何形状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，其将具有优于简单环形通道的若干优点。 它具有简化的入口和出口几何形状，它将使围绕环形圆周的变化的场强度的影响无效，并且对于给定的四极磁体，它将具有增加的分离长度。 目前正在努力优化河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化。 四极磁性FFF提供了表征胶体材料在其磁化分布方面的独特可能性。 其他技术仅产生磁化强度的整体值或平均值。 分销信息对这些材料的制造商来说是非常宝贵的。 加入四极电磁铁将扩大仪器的适用范围。 磁场强度可以调节以适应样品的磁性。 使用程序化的场强衰减，该仪器将能够表征磁性多分散颗粒样品，其中磁化强度在颗粒之间变化很大。 该方法将是有用的表征微粒和胶体。 它还将通过使颗粒表面功能化以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.