A comparative study of tetra-n-butylammonium bromide potentiometric selective screen printed, carbon paste and carbon nanotube modified graphite sensors

Abstract

A comparative study between in situ screen printed (SPE), carbon paste (CPE) and carbon nanotube modified graphite (CNTME) electrodes was established for the determination of tetra-n-butylammonium bromide (TBAB) in pure and spiked tap water samples. Different experimental conditions as ion-pairing agent type and content, carbon nanotube content, plasticizer, response and soaking time, pH and, temperature effects were studied. The in situ SPEs commingling 6 mg sodium tetraphenylborate (NaTPB, electrode I), 6 mg phosphotungstic acid (PTA, electrode II), 6 mg phosphomolybdic acid (PMA, electrode III), and 12 mg ammonium reineckate (RN, electrode IV) ion-pairing agents displayed the best Nernstian slope values of 60.71 ± 1.94, 59.75 ± 0.38, 59.73 ± 0.76 and 59.90 ± 0.51 mV decade−1 over a perceptible spacious concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1, respectively. While it was observed that the in situ CPE containing 9 mg of RN ion-pairing agent (electrode V) presenting Nernstian slope of 60.38 ± 0.16 mV decade−1 over concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1 and in order to improve the efficiency of electrode V, the paste was modified with different amounts of carbon nanotube and the best content was found to be 100 mg of carbon nanotube (electrode VI) with Nernstian slope of 59.90 ± 0.45 mV decade−1 over a broader concentration range from 1.0 × 10−6 to 1.0 × 10−2 mol L−1. The fabricated sensors exhibited fast response time with a relatively low isothermal coefficient. The analytical performance of the SPEs, CPE, and CNTME compared with respect to distinguishing power for TBAB relative to a number of potential interfering cations were investigated. The obtained results were satisfactory with excellent detection and quantification limit, recovery, and relative standard deviation percentages values which indicate the precision and accuracy of the established sensors.