Research on Micro-Liquid Dispensing Anomaly Monitoring System Based on Pressure Sensor

In the sample processing of automated nucleic acid analysis system, abnormal conditions such as clog, air suction, foam and liquid residue can cause unpredictable adverse effects on the accuracy and stability of the micro-liquid dispensing, while the micro-liquid dispensing anomaly monitoring system can monitor the abnormal conditions of the liquid dispensing process in real time and eliminate the failure of the experiment due to the dispensing anomalies of the sample. Air displacement-based micropipette distributes the liquid using the change of air pressure in the piston, so that the abnormal conditions occurring during the liquid dispensing can be monitored in real time and corrected timely by measuring the internal pressure parameters of the piston and collecting the characteristic indexes. To monitor the pressure changes inside the piston in real time, this paper builds an experimental platform for micro-liquid dispensing anomaly monitoring based on the air pressure sensor and piston pump, and sets four abnormal condition monitoring experiments of clog, air suction, foam and liquid residue. Experiments show that the micro-liquid dispensing anomaly monitoring system can successfully capture the above four kinds of liquid dispensing anomalies with good accuracy and stability.