Determination of anionic surfactants in commercial systems with the new potentiometric sensor

Tenzidi su površinski aktivne tvari koje smanjuju površinsku napetost, a struktura im se sastoji od hidrofilne i hidrofobne skupine. Podijeljeni su na anionske, kationske, neionske i amfolitske. Anionski tenzidi su najšire primijenjeni i najčešće se koriste u obliku praškastih deterdženata jer lako uklanjaju mrlje s odjeće. Za određivanje koncentracije tenzida najčešće se koriste potenciometrijske titracije koje koriste ionsko-selektivne elektrode. Određivanje anionskih tenzida u realnom sustavu provedeno je koristeći novi potenciometrijski senzor koji se bazira na ionskom paru dimetildioktadecilamonijevtetrafenilboratu (DDA-TPB) kao elektroaktivnoj komponenti i o-nitrofeniloktileteru (oNPOE) kao plastifikatoru. Kao titrans je korištena standardna otopina cetilpiridinijeva klorida (CPC) koncentracije c = 4·10-3 mol/dm3, a analit je bila vodena otopina praškastog deterdženta Bioflower masene koncentracije γ = 5 g/dm3 koji, prema deklaraciji, sadrži 5–15% anionskih tenzida, dok se natrijev dodecilsulfat (NaDDS) koncentracije c = 4·10-3 mol/dm3 koristio kao standardni dodatak.Surfactants are surface active agents that lower the surface tension and contain hydrophilic and hydrophobic groups. They are divided into anionic, cationic, nonionic and ampholitic surfactants. Anionic surfactants are most widely used, specially in the form of powdered detergents due to their ability to remove stains from clothing. Determination of surfactants concentration is usually carried out by potentiometric titration using ion-selective electrode. Determination of anionic surfactants in real system was carried out using the newly synthesized potentiometric sensor based on an dimethyldioctadecylammonium tetraphenylborate (DDA-TPB) ion pair as the sensing element and o-nitrophenyl octyl ether (o-NPOE) as plasticizer. Standard solution of cetylpyridinium chloride (CPC) at concentration of c = 4·10-3 mol/dm3 was used as titrant, water solution of powdered detergent Bioflower at mass concentration of γ = 5 g/dm3 containing 5–15% surfactants, according to the declaration, was used as analyte and sodium dodecylsulfate (NaDDS) at concentration of c = 4·10-3 mol/dm3 was used as standard addition