Determining salinity using a multimode fiber optic surface plasmon resonance dip-probe

For the first time a fiber optic surface plasmon resonance sensor with demonstrated accuracy and precision of less than 200 ppm salinity is presented for calibration across a range of temperatures and salinities. Also shown is the potential for the sensor system to reach precisions of 10 ppm or less. Calibration models are constructed for 28–48‰ salinity and a method for translating the calibration models to account for varying temperatures between 0 and 25 °C are demonstrated. The long-term susceptibility of the fiber optic sensor to fouling and drift is discussed.