为克服静力称重法受蒸发量影响大的不足,同时适应在线测量的需要,基于Lambert-Beer定律,研究了520nm和730nm双波长超微液体容量光度吸收测量法,通过稀溶液浓度与吸光度之间的线性关系可以计算出待测超微量液体容积。设计了双波长参比光度吸收法的测量系统,采用与静力称重测量系统比对试验的方式对这种方法进行了验证,1μL和5μL微量液体试验数据表明:双波长参比光度吸收法和静力称重法测量结果具有良好的一致性,均符合ISO8655的技术要求。与静力称重法方法相比,双波长参比光度吸收法对测量环境要求低,易于实现在线测量,而且可以有效减少液体蒸发对测量结果的影响。
In order to overcome the shortcoming of significant influence of evaporation capacity on hydro-weighting method, a dual-wavelength photometric method based on Lambert-Beer law at 520 nm and 730 nm was introduced. Micro liquid volume to be measured can be calculated through the linear relation between dilute solution concentration and absorbance. Comparing with the gravimetric method, experimental systems for dual-wavelength photometric method is designed. The test data at 1 μL and 5 μL indicates that dual-wavelength photometric method is in good conformance with gravimetric method, and meet the technical requirement of ISO 8655, but the measured value of dual-wavelength photometric method is a little bigger, dual-wavelength photometric method is able to provide a good solution for micro liquid volume measurement. By comparing with gravimetric method, dual-wavelength photometric method is low in requirement of measurement environment, and easy to realize the online calibration and capable of effectively reducing the influence of liquid evaporation.