Optimization and Applicability of a Novel Sensor for Potentiometric Determination of Anionic Surfactants

Abstract Novel potentiometric sensors for anionic surfactant (AS) determination, with different percentages of tetraoctadecylammonium tetraphenylborate (TODA‐TPB) as sensing materials and different electrolytes (sodium chloride, lithium chloride, sodium dodecyl sulfate (NaDS), sodium tetraphenylborate, sodium acetate, and potassium chloride) at varied concentration levels, were developed and compared. The sensor with best response characteristics was further characterized. It had a fast response time (5 s), a low signal drift (2.0 and 2.9 mV h−1 in a detergent solution and NaDS, respectively), a wide pH working range (3–11), and a longer lifetime of 6 months. This novel sensor was characterized with Nernstian response toward NaDS (−58.0 mV decade−1 of activity), a wide working range (1.3 · 10−7–5 · 10−3 M), and a low limit of detection (1.0 · 10−7 M). It proved to be an accurate and reliable sensor for AS determination in multicomponent mixtures of AS and household wastewater using a potentiometric titration method. Nonionic surfactants, which are commonly mixed with AS in commercial products to obtain better properties of products, had an insignificant impact on AS determination.