Pengoptimuman waktu penyalutan membran PVC dalam pembuatan elektrode selektif ion nitrat

Abstract

Highly concentration of nitrate in environment especially in water can cause health issue. Therefore, nitrate level should be monitored periodically. The presence of nitrate in the water could be detected by ion-selective electrode (ISE) made of coated a wire electrode using polymeric membrane. The objectives of this research are to determine the optimum time of membrane coating and analytical performance of the ISE. The membranes used in this study were composed of, 35% PVC, 61% plasticizer, and 4% aliquot of 336-nitrate with various coating time of 10, 15, 20, 25, and 30 seconds. Based on the results, the optimum time of membrane coating was 20 seconds. ISE III showed the best Nernst factor of 59.70 mV/decade. The best Nernstian response was in concentration range of 10-4–10-1 M. The response time of the developed nitrate ISE was less than 1 minute. The detection limit was found to be 6.14  10-5 M. The developed nitrate ISE did not show interference by NO2 - ion, but encountered interference by the presence of CH3COO-, ClO4 -, H2PO4 -, and SO4 2- ions