Pengaruh Konsentrasi Larutan KHP pada Perlakuan Pasca Elektrodeposisi Elektroda Co-gC untuk Penentuan Fosfat di Tanah secara FIA-Potensiometri

Abstract

One of the phosphate measurements in soil can use cobalt-based selective ion electrodes with glassy carbon (gC) substrates. The method used is Cyclic Voltammetry (CV) electrodeposition with a source of cobalt material CoCl2.6H2O 0.045 M and CoSO4.7H2O 0.045 M. Co-gC electrodes are given post electrodeposition treatment in the form of immersion using Potassium Hydrogen Phthalate (KHP) solution with a concentration variation of 0.005; 0.025; 0.05; 0.075; and 0.1 M for 10 minutes. The optimum Co-gC electrode results between cobalt materials were obtained from soaking a KHP solution of 0.025 M concentration for 10 minutes. Optimum Co-gC electrodes from both material sources were then characterized using standard phosphate solutions of concentrations of 10-3 to 103 ppm on a FIA-Potentiometric basis. The best Co-gC electrode performance results were obtained from the source material CoCl2.6H2O based on sensitivity values of -24.003 mV/decade, linearity 0.9929 and linear regions 10-3 to 103 ppm. The best Co-gC electrodes of both materials were applied to soil samples from Sentool Plantation using the FIA-Potentiometric method. The results of the comparison test of the two material sources showed that the Co-gC electrode from the CoCl2.6H2O material source was better than the CoSO4.7H2O. The results were obtained based on the value of phosphorus levels from the extraction process using Bray P1 extractant (1:50) in each soil sample of avocado, orange and longan fields. The results of phosphorus levels from the CoCl2.6H2O material source showed a 106.54% similarity with the CoSO4.7H2O material source.