| Abstract | U elektrokemijskim mjerenjima često se primjenjuju elektrode na bazi paste od ugljika zbog njihovih dobrih fizikalno – kemijskih svojstava. Ugljikova pasta priprema se miješanjem ugljikovog materijala, veziva, ionsko – asocijacijskih kompleksa (IAC – a), a da bi se poboljšale odzivne karakteristike elektroda u ugljikovu pastu se mogu dodati modifikatori. Pripremljeno je i ispitivano 29 pasti s ciljem dobivanja senzora za potenciometrijsko određivanje acebutolola. Svaka elektroda ispitivana je u vremenskom periodu od dva dana u koncentracijskom području od 3,16 x 10 -6 mol L -1 do 3,16 x 10 -3 mol L -1 , pri pH vrijednosti od 4,5. Najbolje odzivne karakteristike pokazala je elektroda 7 koja sadrži 54,9% grafita, 44,8% dibutil-ftalata (DBP) i 0,3% acebutolol fosfovolframata (AC – PTA), a ostvareni nagib iznosi 42,9 mV. Dodatak ionskih aditiva, s ciljem poboljšanja osjetljivosti elektroda, očitovao se samo kod elektrode 28 koja sadrži 54,0% grafita, 44,1% dibutil- ftalata (DBP), 1,5% acebutolol fosfovolframata (AC – PTA) i 0,4% natrijevog tetrafenilborata (NaTPB), a ostvareni nagib iznosi 40,8 mV. |
| Abstract (english) | Electrodes based on carbon paste are often used in electrochemical measurements due to their good physical and chemical performance. Carbon paste is prepared by mixing carbon material, binder, ion – association complexes (IAC – a), and in order to improve the response characteristics of the electrodes, modifiers can be added to the carbon paste. It was prepared and tested 29 pastes were with the aim of obtaining a sensor for the potentiometric determination of acebutolol. Each electrode was tested over a period of two days in the concentration range from 3.16 x 10 -6 mol L -1 to 3.16 x 10 -3 mol L -1 , at a pH value of 4.5. The best response characteristics were shown by electrode 7, which contains 54.9% graphite, 44.8% dibutylphthalate (DBP) and 0.3% acebutolol phosphotungstate (AC – PTA), and the achieved slope is 42.9 mV. The addition of ionic additives, with the aim of improving the sensitivity of the electrodes, manifested itself only in electrode 28, which contains 54.0% graphite, 44.1% dibutylphthalate (DBP), 1.5% acebutolol phosphotungstate (AC – PTA) and 0.4% sodium tetraphenylborate (NaTPB), and the achieved slope is 40.8 mV. |
