光密度的由来及其物理意义

THE ORIGIN AND PHYSICAL MEANING OF THE OPTICAL DENSITY

光密度（ＣＤ）及其衍生参量积分光密度（ＩＯＤ）是生物医学特别是分子生物学实验中所需测定的重要参数。ＯＤ来源于Ｌａｍｂｅｒ－Ｂｅｅｒ定律，它仅与样品中所测位置上的阳性物质的含量有关。ＩＯＤ为样品中的所测区域内的各点光密度的总和，它与样品中所测区域内的阳性物质总的含量有关。施加了本底修正，ＯＤ就能客观地、科学地反映出样品中所测位置上的阳性物质的真实含量。ＩＯＤ也是如此。在具体测定一批样品ＯＤ前，还必须注意诸如光源选择等问题。

Optical Density(OD) and Integrated Optical Density(IOD) derived from it are the important parameters which must be measured in the experiment of the bilogical medicine,particularly of the molecular biology.OD,which originates from Lamber-Beer law,relates to the quantity of the positive material contained on the position in a sample where the OD is detected.IOD of a region of the sample,which is defined as the sum of the ODs of all the positions in the region,relates to the sum of the quantity of the positive material contained on the region of the sample in which the OD of every position is detected.Revised with the background,the OD can represent the real quantity of the positive material scientifically and objectively,so does the IOD. Some questions,such as the election of the light source and so on,must be taken into consideration before the detection of the OD for a new lot of samples in begun.