X-ray computed tomography (CT) and focused ion beam (FIB) microscopy were used to generate three dimensional representations of chromatography beads for quantitative analysis of important physical characteristics including tortuosity factor. Critical-point dried agarose, cellulose and ceramic beads were examined using both methods before digital reconstruction and geometry based analysis for comparison between techniques and materials examined.

X-ray ‘nano’ CT attained a pixel size of 63 nm and 32 nm for respective large field of view and high resolution modes. FIB improved upon this to a 15 nm pixel size for the more rigid ceramic beads but required compromises for the softer agarose and cellulose materials, especially during physical sectioning that was not required for X-ray CT. Digital processing of raw slices was performed using software to produce 3D representations of bead geometry.

Porosity, tortuosity factor, surface area to volume ratio and pore diameter were evaluated for each technique and material, with overall averaged simulated tortuosity factors of 1.36, 1.37 and 1.51 for agarose, cellulose and ceramic volumes respectively. Results were compared to existing literature values acquired using established imaging and non-imaging techniques to demonstrate the capability of tomographic approaches used here.

X射线计算机断层扫描（CT）和聚焦离子束（FIB）显微镜用于生成色谱珠的三维表示，用于定量分析包括曲折因子在内的重要物理特征。在数字重建和基于几何的分析之前，使用两种方法检查了临界点干燥的琼脂糖，纤维素和陶瓷珠，以比较所检查的技术和材料。

对于各自的大视场和高分辨率模式，X射线“纳米” CT的像素尺寸分别为63 nm和32 nm。FIB对此进行了改进，以使像素更硬的陶瓷珠达到15 nm，但需要对较软的琼脂糖和纤维素材料进行折衷，特别是在X射线CT不需要的物理切片过程中。使用软件对原始切片进行数字处理，以生成3D珠子几何图形表示。

评估每种技术和材料的孔隙率，曲折系数，表面积与体积之比和孔径，琼脂糖，纤维素和陶瓷体积的总体平均模拟曲折系数分别为1.36、1.37和1.51。将结果与使用已建立的成像和非成像技术获得的现有文献值进行比较，以证明此处使用的层析成像方法的能力。