Document Type : Original Article
Volyn National University, Voli av. 13, Lutsk 43021, Ukraine
Vladimir Vinnichenko Central Ukrainian State Pedagogical University, Shevchenko str. 1, Kropivnitsky, 25000, Ukraine
Pavlo Tychyna Uman State Pedagogical University, Sadova st. 2, Uman, Cherkasy region, 20300, Ukraine
Chernivtsi National University, Kotsyubyns’ky Str., 2, Chernivtsi, 58012, Ukraine
Mefenamic acid (Mef) is a derivative of phenylanthranilic acid (Paa). As a drug of the NSAID group, it reduces the sensation of pain and suppresses the development of inflammation in the human body. For its determination, in substance and dosage forms (tablets, capsules, gels) different methods of analysis are used. Ionic associate (IA) compounds of Mef and Paa with rhodamine 6G were used as electroactive substances (EAS) in the manufacture of membranes of ion-selective electrodes. Investigation of the electrochemical properties of the obtained ISEs with different contents of the EAS (1-10%) shows that they give an answer to the concentration of Mef and Paa in a solution in a wide range: 5×10-4-1×10-2 and 2×10-3-1×10-1 mol/l, with the slope of 83.1 and 89.1 mV/рС respectively. The content of the EAS in the composition of the membrane with a content of 4-8% slightly affects the basic electroanalytical characteristics of the sensors manufactured. Further, an increase in the content of the associate leads to thickening and increases the rigidity of the membrane, which causes the deterioration of the steepness value and the limits of detection of the test substance. Significant influence on the results of the work of the electrodes may alter the quantitative content of the plasticizer in the membrane. The research was carried out for membranes containing DBF of 35-75%. As a result of measurements, it was found that electrodes with content of plasticizer of 45-70% possess good electroanalytical characteristics. The operating range of the acidity of the functioning of the electrode is equal to the pH range 9-11. Stable values of electrode potentials are set within 5-10 seconds. Synthetic membranes are suitable for work for at least 4 months. Efficient techniques of the potentiometric determination of the content of mefenamic and phenylanthranilic acids in model solutions and pharmaceuticals were developed.