Abstract:

Seawater chlorophyll-a sensors are essential tools for marine ecological monitoring, enabling the detection of spatial and temporal variations in chlorophyll-a concentration. However, these sensors are susceptible to measurement drift, which can compromise data reliability. This study proposes a metrological approach for evaluating sensor performance using fluorescein sodium as a reference standard. Sensor performance was assessed in terms of linear response range, accuracy, precision, and stability. Results indicated a strong positive correlation between fluorescence intensity and fluorescein concentration. Based on the fitted calibration curve, indication error and standard deviation were calculated. The linear response range was determined by controlling the correlation coefficient, whereas stability was assessed through repeated measurements over different time periods. Within the linear range of 0 to 200 μg/L, the maximum measurement error was ≤2.00 μg/L, and the relative standard deviation was <0.20%. The sensor exhibited consistent performance from 2021 to 2022. Maintaining consistent pipetting accuracy was identified as a critical factor for ensuring measurement reliability.

Key words: seawater chlorophyll-a senaor, fluorescence standard material, evaluation method, pipette accuracy