Accuracy and dynamics of flow measurements to 1 nL/min using an optofluidic flow meter

There is a growing need for accurate and fast flow meters that operate at the sub-100 nL/min range. We previously described an optofluidic flow meter that uses the photobleaching of a fluorescent dye in a microchannel as a reporter of flow rate [1]. Herein we use the optofluidic flow meter to study the continuous flow of commercially available syringe pumps with nominal settings ranging from 1 nL/min to 500 nL/min. Results are compared with thermal flow meters. We demonstrate higher accuracy, lower noise floor, and faster dynamic measurement capability of the optofluidic flow meter relative to the other instruments. These capabilities will enable technology development by facilitating optimization of microfluidic processes.