Optical Portable Dissolved Oxygen Meter DOS-118G The BOQU Instrument launched a new optical portable dissolved oxygen meter. Unlike traditional electrochemical sensors, optical dissolved oxygen sensor use fluorescence quenching techniques. This technique is based on a proven method for accurately measuring dissolved oxygen concentrations. The concentration of oxygen in the water can be measured by the quenching effect of the fluorescent substance on the surface of the sensor, without the need for internal filling, and without the need for preheating. The sensor has a fast response, does not consume dissolved oxygen, from the flow rate and the impact of test solution dirt and so on.