HIGH-PRECISION SEAWATER PH IN-SITU MEASUREMENT SYSTEM AND METHOD BASED ON INTEGRATED VALVE-TERMINAL APPARATUS

High-precision Seawater pH in-situ Measurement System and Method based on Integrated Valve-terminal ApparatusThe present invention belongs to the technical field of marine monitoring, and specifically relates to a high-precision seawater pH in-situ measurement system and method based on an integrated valve-terminal apparatus capable of testing multiple reagents. The measurement system comprises a flow path module, an optical path module, and a circuit module; the flow path module comprises an integrated valve terminal which controls the direction of the flow path, said flow path module being used for performing seawater sample injection, reagent sample injection, and mixing; the flow path is controlled by means of the integrated valve terminal; when measuring the seawater pH in situ, first, seawater is injected into the flow path to determine the blank light intensity; then an indicator is injected into the flow path, the flow path is closed into a loop, and seawater and the indicator are mixed in the loop; after mixing is complete, the light intensity of the mixed solution is measured, the absorbance is calculated, and thus the seawater pH is calculated. A valve terminal apparatus is used as the flow path structure of the present invention, and has the features of small dead volume, compact structure, and low power consumption, and is capable of achieving complete mixing of seawater and indicator, improving the stability of instrument measurement.