Josip Juraj Strossmayer University of Osijek. Department of Chemistry. Department of Analytical, Organic and Applied Chemistry.
Abstract
Novi potenciometrijski senzor za anionske tenzide pripremljen je na osnovi višestjenčanih ugljikovih nanocjevčica (MWCNT) koji su upotrebljene za imobilizaciju 1,3-didecil-2-metilimidazol tetrafenilborat (DMI-TPB) ionskog para kao ionofora u membrani. Istraživani senzor pokazao je Nernstovski odziv za dodecilbenzensulfonat i dodecilsulfat. Odziv je prikazan unutar 8-10 sekundi za svaku deseterostruku promjenu koncentracije u rasponu od 1 x 10-7 M do 1 x 10-3 M. Granice detekcije za DBS i DS su 1 x 10-6 i 2 x 10-7 M. Senzor daje stabilan potenciometrijski odziv, te pokazuje zadovoljavajuću selektivnost za DS. Glavna primjena senzora je bila u otkrivanju završnih točaka u potenciometrijskim titracijama anionskih tenzida. Hyamine 1622, heksadeciltrimetilamonijev bromid i cetilpiridinijev klorid su testirani kao potencijalni kationski titranti i svi su dali analitički upotrebljive titracijske krivulje s dobro definiranim točkama ekvivalencije. Operativni životni vijek opisanog senzora je oko 3 mjeseca.A new potentiometric anionic surfactant sensor was prepared based on multi-walled carbon nanotubes (MWCNTs) used for immobilisation of 1,3-didecyl-2-methylimidazolium tetraphenylborate (DMI-TPB) ion pair as ionophore in the membrane. The investigated sensor showed a Nernstian response for both dodecylbenzenesulphonate and dodecyl sulphate. It responded in 8-10 seconds for each ten-fold concentration change in the range of 1 x 10-7 M to 1 x 10-3 M. The detection limits for DBS and DS were 1 x 10-6 and 2 x 10-7 M, respectively. The sensor revealed a stable potentiometric response and exhibited satisfactory selectivity for DS. The main application of the sensor was in the end-point detection in potentiometric titrations of anionic surfactants. Hyamine 1622, hexadecyltrimethylammonium bromide and cetylpyridinium chloride were tested as potential cationic titrants, and all exhibited analytically usable titration curves with well-defined equivalence point. The operational life time of the sensor described amounted ca. 3 months
