The generation of bubbles and cross contamination are two major challenges that affect the accuracy and reliability of experiments during the digestion tube transfer process, and accurate liquid level detection technology is the key to solving these challenges.

Accurate liquid level detection to avoid bubble formation

Bubbles are often generated due to improper insertion speed or inaccurate detection of the pipette into the liquid surface. The advanced liquid level detection system adopts capacitive or pressure sensing detection technology. Capacitive detection determines the position of the liquid level by measuring the change in capacitance between the pipette and the liquid, which can sensitively sense the liquid level and allow the pipette to be inserted at an appropriate speed, avoiding the formation of bubbles caused by liquid splashing due to rapid insertion. Pressure sensing detection is based on the change in pressure when the pipette touches the liquid surface, accurately controlling the insertion depth and reducing the mixing of bubbles. During the pipetting process, the system precisely controls the amount of liquid suction based on the detected liquid level height, preventing the generation of bubbles due to inaccurate suction causing pressure changes inside the tube.

Liquid level detection strategy to prevent cross contamination

Cross contamination mainly comes from the residual liquid carried by the transfer needle from the previous transfer. To avoid this problem, the liquid level detection system can be linked with the pipette cleaning device. Before each transfer, the detection system first determines the liquid level of the digestion tube. After completing the transfer, the transfer needle moves to the cleaning position, and the cleaning device flushes the inner and outer walls of the transfer needle. At the same time, using disposable pipetting needles is also an effective way. After the detection system accurately locates the liquid level, the disposable needle completes the suction and discharge operations, and is discarded after use, fundamentally eliminating cross contamination. In addition, some liquid level detection systems also have liquid level recognition function, which can distinguish different liquids. When the properties of the detected liquid do not match the preset, it automatically stops pipetting and alarms to prevent cross contamination caused by aspiration.