As for photometry analysis, increasing the optical-path (OP) via multi-reflection is an effective method for improving the detection sensitivity. In this paper, a photometer based on axial multi-reflection between two end-faces of capillary was proposed and investigated. The probe light can be back and forth reflected inside the capillary, by employing apertured silver-mirrors at both ends of a metal-capillary. With designed aperture profile (i.e., a central disc-aperture and a peripheral ring-aperture) of the mirror, a 4.2-fold enhancement on OP was realized (i.e., OP is 4.2 times the capillary length). Moreover, the photometer was applied to detecting nitrite with a detection limit of 1 nM, which exhibits 8.6~15 fold improvement compared with that of previous photometers with similar capillary length and the same chromogenic reagent without sample enrichment. The photometer features compact, low cost and easy fabrication.

对于光度分析，通过多次反射增加光程（OP）是提高检测灵敏度的有效方法。在本文中，一种基于轴向的光度计提出并研究了毛细管两个端面之间的多重反射。通过在金属毛细管的两端使用有孔的银镜，探测光可以在毛细管内来回反射。通过设计的反射镜孔径轮廓（即中心圆盘孔径和外围环形孔径），实现了 4.2 倍的 OP 增强（即 OP 是毛细管长度的 4.2 倍）。此外，该光度计用于检测亚硝酸盐，检测限为1 nM，与之前毛细管长度相似、显色试剂相同且无需样品富集的光度计相比，提高了8.6~15倍。该光度计具有结构紧凑、成本低和易于制造的特点。