Dual-channel concave-shape optical coupling liquid sensing system

A portable liquid sensing system based on a dual-channel and concave-shape optical coupling sensor array is developed for in-situ quantitative measurement of a liquid sample. The liquid sensing cell is specially designed by Multigassensors GmbH. In the cell, three light emitting and sensitive units with different light wavelength are integrated in a SiO2 base. Each unit is composed of one light-emitting diode and two light-sensitive diodes. The cell is a concave-shape with a dual optical channel. The portable liquid sensing system is constructed by the sensing cell and peripheral devices which achieve functions of data acquisition, signal processing and mode identification. With different light absorption property for particular light wave, the tested liquid sample with different components and contents will produce special light response mode. Using the advanced sensor array signal processing algorithm and mode identification method, quantitative liquid measurement can be achieved in-situ by the portable system. The pH measurement for abromcresol green liquid sample is made using the present system and is compared with the result from a spectrometer. The accordant values from these two different devices demonstrate the feasibility of the novel liquid detection method and validity of the developed sensing system.