Rezenom Yohannes H, Wellman Amber D, Tilstra Luanne, Medley Colin D, Gilman S Douglass
Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
Analyst. 2007 Dec;132(12):1215-22. doi: 10.1039/b709509k.
Separation and detection of individual submicron polystyrene spheres using capillary electrophoresis with laser-light-scattering detection has been demonstrated. Electrophoretically separated particles were passed through a focused laser beam and light scattered from individual particles was collected at 90 degrees. Each diameter of polystyrene spheres injected (from 110 to 992 nm) resulted in the observation of a well-defined migration window containing multiple peaks, each arising from the light scattered by an individual particle. The migration time window for individual particles of a particular size corresponded well to the migration time of a peak from a population of particles of the same size detected using a UV absorbance detector. The electrophoretic mobility and scattered light intensity were determined for each particle detected. The average scattered light intensity for each particle size was consistent with Mie scattering theory. Particles as small as 110 nm in diameter were detected individually using this method, but particles with a diameter of 57 nm could not be individually detected. The number of single particle scattering events was counted and compared to the theoretical number of particles injected electrokinetically, and the detection efficiency determined ranged from 38 to 57% for polystyrene spheres of different sizes. The laser-light-scattering detection method was directly compared to laser-induced fluorescence detection using fluorescent polystyrene microspheres. The number of particles detected individually by each method was in agreement.
已证明使用带有激光散射检测的毛细管电泳可对单个亚微米聚苯乙烯球体进行分离和检测。经电泳分离的颗粒穿过聚焦激光束，从单个颗粒散射的光在90度角处收集。注入的聚苯乙烯球体的每个直径（从110到992纳米）都导致观察到一个定义明确的迁移窗口，其中包含多个峰，每个峰都来自单个颗粒散射的光。特定尺寸单个颗粒的迁移时间窗口与使用紫外吸收检测器检测到的相同尺寸颗粒群体中一个峰的迁移时间非常吻合。对检测到的每个颗粒测定其电泳迁移率和散射光强度。每个粒径的平均散射光强度与米氏散射理论一致。使用此方法可单独检测直径小至110纳米的颗粒，但无法单独检测直径为57纳米的颗粒。对单颗粒散射事件的数量进行计数，并与电动注入的理论颗粒数量进行比较，对于不同尺寸的聚苯乙烯球体，确定的检测效率在38%至57%之间。将激光散射检测方法与使用荧光聚苯乙烯微球的激光诱导荧光检测直接进行比较。每种方法单独检测到的颗粒数量一致。
