吸头(Tip)与钢针精确微量加样方法的性能差异OA

To investigate the performance differences between the tip and steel needle methods in high-precision micro liquid handling and the influence of environmental factors,a comparative study is conducted.Based on fluid dynamics theory,a fluid dynamic model of the liquid handling system is first established to analyze the mechanisms by which temperature and atmospheric pressure affect dispensing accuracy.Through simulation analysis,the variation of residual liquid volume on the inner wall of the steel needle during the aspiration of the isolation air column is studied with respect to aspiration speed and air column volume.An experimental platform is set up,and a gravimetric method is employed to test the performance of both methods under different temperatures(15～35℃)and atmospheric pressures(50～101 kPa).The results show that both increasing temperature and decreasing atmospheric pressure lead to reduced dispensing accuracy for both methods,with the TIP method exhibiting more significant deviation.The repeatability of the TIP method deteriorates notably for small volumes(5 μL),and the 100 μL dispensed volume decreases by approximately 4 μL at 35℃compared to 25℃.The residual liquid volume on the inner wall of the steel needle increases with aspiration speed,reaching 0.78 μL at 120 μL/s,with the liquid primarily remaining at the needle tip and tapered section.Compared to existing research,this study quantifies the extent of environmental impacts on the two liquid handling methods and clarifies the higher sensitivity of the TIP method to environmental changes.It is concluded that to improve micro liquid handling accuracy,the temperature around the dispensing needle should be kept constant,the air column design should be optimized,sensor-based compensation should be implemented,and aspiration speed should be reduced to minimize residual liquid in steel needles.The study provides a theoretical basis and practical guidance for the optimal design of micro liquid handling technology.