Assembly and Application of New Calcium Ion –Selective Electrode for Determination of Calcium Ions .


Abstract:A new calcium ion- selective electrode was prepared from calcium glyxolate complex doped with PVC and plasticizer .The electrode was characterized by its stable Nernstian response 29.97mV/decade. with a linear range of ( 10 -5 - 10-1 ) M , detection limit of 10-5 M and response time of ( 20 - 60 sec.) within the electrode lifetime which lasted four months. Suitable pH range for electrode response was (5 - 9) and little temperature effect was found on the efficiency of the electrode. High selectivity of the electrode to calcium ions in the presence of many cation was found which clarified from the lower potentiometric selectivity coefficients . Most of the anions are severely interfered as a result of precipitation or stable complex formations with calcium ions and these interferents were exploited in the determination of the anions or the calcium ions. Encouraging and promising results were obtained using this new calcium ISE in the determination of calcium in drinking water and human blood serum coincidental with the spectrophotometric methods.