自动光谱滴定装置的研发

Development of automatic spectral titration device

为满足前沿科学研究对化学分析准确度、便携性和可靠性的要求,研发了一款基于光谱分析,利用滴定终点指示剂颜色突变原理进行滴定终点判定的自动滴定装置。该装置通过控制步进电机配合滚珠丝杠的方式,利用电机的扭矩驱动精密进样器推杆进行直线运动,从而实现自动滴液、补液的功能。使用微型光谱传感器,对滴定过程中溶液的颜色进行连续采集,并且实时进行光谱分析,最后以相关系数法为主体算法,进行滴定终点的判定。设计上位机软件,实现滴定实时控制、滴定曲线实时绘制、滴定数据保存等一系列人机交互功能。利用该装置进行滴定控制精度试验和酸碱中和滴定试验,减小传统人工滴定存在的误差,提高滴定分析效率,降低人力消耗。试验结果表明,装置的平均相对误差为0.6493%,相对标准偏差为0.3071%,对比酸度计试验结果,误差更小,稳定性更好,由此可见该装置可以满足前沿科研的分析需求,在化学分析自动化、智能化具有实际应用意义与推广价值。

In order to meet the requirements of frontier scientific research for chemical analysis accuracy,portability and reliability,an automatic titration device based on spectral analysis and using the principle of sudden color change of titration endpoint indicator for titration endpoint determination was developed.The device realizes automatic titration and replenishment by controlling a stepper motor with a ball screw and using the torque of the motor to drive the precision feeder pusher in a linear motion.A miniature spectral sensor is used to continuously collect the color of the solution during titration and perform spectral analysis in real time,finally,the correlation coefficient method is used as the main algorithm for the determination of the titration endpoint.The upper computer software is designed to realize a series of human-computer interaction functions such as real-time titration control,real-time titration curve drawing,and titration data saving.The titration control accuracy test and acid-base neutralization titration test were carried out with the device to reduce the errors of traditional manual titration,improve the efficiency of titration analysis and reduce the labor consumption.The test results show that the average relative error of the device is 0.6493%and the relative standard deviation is 0.3071%,which less error and better stability compared to acidity meter test results,it shows that the device can meet the analytical needs of cutting-edge scientific research and has practical application and promotion value in the automation and intelligence of chemical analysis.