基于LAPS的H^+检测系统的研究与分析

Research and analysis of H^+ detection system based on light addressable potentiometric sensor

以H+为检测对象,设计了基于光寻址电位传感器(Light Addressable Potentiometric Sensor,LAPS)的H+检测系统。该系统以LAPS为前端传感元件,以Smacq USB3112数据采集卡为控制平台,采用LabVIEW软件设计系统控制和信号处理程序。分析了该系统对H+检测的灵敏度、线性度和重复性,在光源调制信号的偏移量为2. 5 V、幅值为1. 5 V、频率为4 k Hz情况下,灵敏度为51. 1 m V/p H、非线性误差为0. 022%、重复性误差为0. 004%。本文设计的检测系统对常见干扰离子K+、Ca2+、Na+、Mg2+的检测灵敏度分别为4 m V/pK、6 m V/p Ca、7m V/p Na、4 m V/pMg,显著低于对H+的检测灵敏度。研究结果表明,该H+检测系统不仅具有较高的检测灵敏度和线性度,而且具有良好的重复性和测量选择性。

An H+detection system based on Light Addressable Potentiometric Sensor(LAPS)is designed.LAPS is used as the front-end sensor and Smacq USB3112 data acquisition card is adopted as the control platform of this detection system.LabVIEW software is utilized for system control and signal processing.The sensitivity,linearity and repeatability of this system for H+detection are analyzed in this paper.When the offset of modulated light signal is 2.5 V,the amplitude is 1.5 V,and the frequency is 4 KHz,the measured sensitivity,nonlinear error and repeatability are 51.1 m V/pH,0.022%and 0.004%,respectively.The measured sensitivities of the system to common interference ions K+,Ca2+,Na+,and Mg2+are 4 m V/pK,6 m V/pCa,7 m V/p Na,and 4 m V/pMg,which are significantly lower than that to H+.These measured results show that the H+detection system has high detection sensitivity,linearity,repeatability and excellent measurement selectivity.