Journal of Marine Sciences ›› 2021, Vol. 39 ›› Issue (2): 52-59.DOI: 10.3969/j.issn.1001-909X.2021.02.006

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Calibration and correction method of self-developed high-accuracy pH sensor and their application in in-situ observation of seawater

JIN Quan1, ZHANG Chuqing1,2, WU Jianbo1, ZHANG Xiao3, YE Ying1, HUANG Yuanfeng*4, TAO Chunhui2#br#   

  1. 1.Ocean College, Zhejiang University, Zhoushan 316021, China; 
    2.Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China; 
    3.CETCHIK Group Co., Ltd., Hangzhou 311100, China; 
    4.Shandong SEI Science & Technology Co., Ltd., Ji’nan 250002, China
  • Online:2021-06-15 Published:2021-06-15

Abstract: Electrochemical methods are the main methods for measuring seawater pH. The self-developed electrochemical pH sensor is based on iridium metal and its oxide electrode, a method for its calibration and data correction in seawater environment was established and applied for in-situ testing in nearshore and oceanic environments. The instrument calibration includes (1)Selecting appropriate calibration buffer reagents according to the calibration requirements of seawater pH analysis; (2)Preparing calibration buffer system by replacing the commonly used 2-aminopyridine (AMP) solution with standard seawater. Data correction mainly includes temperature background correction and error correction. Insitu testing in the sea area and comparison with other similar instruments show that the error caused by the difference of calibration system can be up to 1.00 pH unit, and the data correction can improve the testing accuracy from 0.10 pH unit to 3.00 pH unit. The calibration and data correction method of the instrument can effectively improve the measurement accuracy of this self-developed pH sensor.

Key words: seawater pH, in-situ test, electrochemical sensor, calibration, correction

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