A new paradigm for Light-addressable potentiometric sensor detection based on Gaussian fitting

Light-addressable potentiometric sensor (LAPS) is a low-cost and versatile semiconductor field-effect pH sensor. The measurement of pH by traditional LPAS usually adopts the way of normalizing the V-I characteristic curve, which needs to obtain the data of the whole V-I characteristic curve, resulting in slow measurement speed and long time. To address this problem, a new $\mathbf{p H}$ measurement method is proposed in this paper, which integrally considers the nonlinear error in the linear region by fitting a Gaussian function to the local linear region of the V-I characteristic curve, and the measurement results are directly obtained from the parameters of the fitted function. The experimental results show that the sensitivity and repetition rate of the new detection method can be comparable with that of the V I characteristic curve measurement method, and the linearity is improved by 0.81%, which helps to improve the measurement efficiency and realize the rapid measurement of pH.