Devolopping ion selective membrane electrode for potassium based on crown ether and applications

vDEVOLOPPING ION SELECTIVE MEMBRANE ELECTRODE FORPOTASSIUM BASED ON CROWN ETHER AND APPLICATIONS(M.Sc. Thesis)Erdal PEÇENEKGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYFebruary 2007ABSTRACTA new membrane electrode selective to K+ ion has been developed based oncrown ether in this study. The membrane consisted of benzo-15-5 crown etheras a neutral carrier, orto-nitrophenylphenyl ether as plasticizer increaser andPVC as membrane matrix. An analytically useful potential change occurs in the1x10-4-1x10-2 M concentration range. The slope of linear portion was 49,1±2,4mV/10-fold concentration changes in potassium concentration. In the presenceof 1x10-3 M K+ no interference was observed for Li+, Na+, NH4+, Mg2+, Ca2+,Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cr3+, Fe3+, ve F-, Br-, I-, NO2-, SO42-,CO32-, S2- ions. The measurements were made at constant ionic strength (0,1 MNaNO3, medium) and at room temperature(220C). The lifetime of the electrodewas approximately 3 months when used twice a day and the response time wasabout 30 seconds. This electrode has been used for the determination of K+ byapplying standart addition method for orange juice, vitamin pill and edible salt.The amount of K+ in the samples was found 1,9 ± 0,1 mg/mL for orange juice,0,53 ± 0,008 % (m/m) for vitamin pill and 0,48 ± 0,1 % (m/m) for edible salt.Science Code : 201.1.004Key Words : Ion selective electrode;potassium ion; crown etherPage Numbers : 88Adviser : Asist.Prof.Dr. Olcay ŞEND L