Development of A Potentiometric Portable Extractor for Phosphate using Water Absorbent Materials and Cobalt Wire Electrodes

¹ Chemical Sensor and Instrumentation Research Group, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Jember, Jl. Kalimantan No. 37 Jember 68121
² Biomaterial Research Group, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Jember, Jl. Kalimantan No. 37 Jember 68121

^* Corresponding author: siswoyo@unej.ac.id

Abstract

Soil phosphorus is an essential nutrient in the soil and is very necessary for plants, so measuring the content of elements or their derivatives in the soil is very necessary. This study aimed to develop a portable measuring instrument for phosphate based on the potentiometric principle using cobalt electrodes. The choice of absorbent material to support portable measuring instruments is based on water absorption and the potential response of the cobalt electrode when used with an absorbent. The phosphate electrode was made from cobalt wire and Ag/AgCl as a reference electrode. A comparison of analysis results was carried out between portable extraction potentiometric and conventional potentiometric methods. The results showed that polyvinyl alcohol (PVA) was the best absorbent. Using potentiometric measurements in a portable extractor prototype with PVA as an absorbent material offers promising prospects. The comparison of measurement results between the portable extractor and conventional potentiometric had 0.8039 as the correlation coefficient. Phosphate in conventional potentiometric was measured 1.2809 times higher than portable extraction potentiometric. The potentiometric slopes were -23.69 mv/decade and -26.63 mv/decade for the portable extractor potentiometric and the traditional potentiometric methods, respectively.