加样方法是影响加样精度的关键因素之一。非接触式加样已经成为当前微量生物试剂加样技术的主要发展方向。理论分析了加样量与步进电机加速度之间的关系,并基于SF-8000全自动凝血分析仪的微量加样系统,设计了步进电机的微步控制模块。通过试验验证分析,探讨了一种可应用于该系统的非接触式微量加样方法。介绍了加样系统的结构及工作原理,并从理论上分析了非接触式加样中的最少加样量;搭建了试验系统,并在不同加样加速度的情况下对分液量进行收集称重,获得了加速度与加样量的关系。试验结果表明,在上位机确定加样量的前提下,当加速度为1 000 step/s2时,加样量波动最小,重复性CV为2.071%,满足应用要求。该方法还可应用于其他生物医疗仪器的非接触式微量自动加样设计中。
The method of pipetting is one of the critical factors influencing the accuracy of pipetting, while noncontact pipetting has become the main developing direction of microscale biological reagent pipetting technology. The relationship between the pipetting volume and the acceleration of the stepping motor is analyzed theoretically ; and the micro step control module is designed based on the microscale pipetting system of SF - 8000 fully automated blood coagulation analyzer. Through experimental verification analysis,the noncontact microscale pipetting method which can be used in this system is investigated. The structure and operational principle of the pipetting system are introduced ; and the minimum pipetting volume in noncontact pipetting is analyzed theoretically,the test system is setup, and under different pipetting acceleration, tile pipetting volume is collected and weighted,thus the relationship between acceleration and pipetting volume is obtained, The test results show that under the pipetting volume determined by the host computer, when the acceleration is 1 000 step/s2, the fluctuation of pipetting volume is minimized ,and the repeatability of CV is 2.071% ,which meets the requirement of application. The method also can be applied for designing noncontact auto microscale pipetting in other biological medical instruments.