磁珠广泛应用于免疫检测、细胞分离等生物实验中, 磁珠浓度的检测对于评价实验效果具有重要意义。本文提出了基于激光透射法的双光路磁珠浓度测量系统, 通过测量入射激光强度与透射激光强度的比值来确定磁珠浓度。利用该系统对多个浓度的磁珠悬浊液进行了实验测量, 每个浓度下测量多组实验数据, 共采集了8 000组数据。通过拟合测量数据, 建立了磁珠浓度与测量值的关系函数, 二者呈现指数函数关系, 拟合残差平方和为0.000 088 89, 确定系数可达0.997 1, 说明函数具有良好的拟合性能。实验结果表明, 相对测量误差在2.5%以内, 输出值相对波动范围在2.5%以内, 测量系统具有较高的测量精度和良好的重复性。

Magnetic beads are widely used in biological experiments, such as immunoassay and cell separation. The detection of magnetic concentration is profound to the evaluation of experimental results. Therefore a magnetic beads concentration measuring system with dual optical path based on laser transmission method was presented. The concentration of magnetic beads was determined by measuring the ratio of the intensity of incident laser to the intensity of the transmitted laser. A series of magnetic bead suspensions with various concentrations were tested. For each concentration, the measurement was performed for many times and a total of 8,000 sets of data were collected. By fitting the measured data, the relational function between beads concentration and output data can be obtained. The relation between the concentration of magnetic beads and output data was well fitted exponentially. The fitting residual sum of squares is 0.000 088 89 and the determination coefficient is 0.997 1, which illustrate good fitting ability of the model. The experimental results show that the relative measurement error is less than 2.5% and the output data fluctuates within 2.5%, which indicate that the beads concentration measurement system based on laser transmission has high measurement accuracy and good repeatability.