In-Soil Potassium Sensor System

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• 作者：Sherlan G. Lemos ; Ana Rita A. Nogueira ; André ; Torre-Neto ; Aleix Parra ; Judit Artigas ; and Julian Alonso
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2004
• 出版时间：September 22, 2004
• 年：2004
• 卷：52
• 期：19
• 页码：5810 - 5815
• 全文大小：118K
• 年卷期：v.52,no.19(September 22, 2004)
• ISSN：1520-5118

文摘

A potentiometric sensor system based on potassium ion-selective electrodes was developed foragricultural purposes. Sensors were built using PVC ion-selective membranes over an inner solidcontact prepared with graphite-epoxy composites. A copper plate was used as a reference electrode.A two-stage electronic circuit composed of current and voltage amplifiers was designed to interfacethe sensors to a distributed data acquisition system. Three ion-selective sensors and three off-the-shelf temperature sensors and their associated circuits were mounted in a PVC tube to set up a soilprobe. The electronic controls were placed in an airtight box fixed at the upper part of the probe. Thesystem was evaluated in the field, where the sensors presented sensibility within the range of 69-71 mV dec^-1. Extracts of soil samples were analyzed by a current flame photometry approach, andthe results, compared with the probe measurements, showed a linear relationship (r ² = 0.992 and0.995, respectively, to 5 and 20 cm depths), which implies viability and instrumentation reliability foragricultural applications.Keywords: Potassium; in-situ; soil analysis; soil fertility; potentiometric sensor