A New Sensor for Determination of Anionic Surfactants in Detergent Products with Carbon Nanotubes as Solid Contact

Abstract

A new solid‐state sensor for potentiometric determination of surfactants with a layer of multi‐walled carbon nanotubes was prepared. As a sensing material, 1,3‐didecyl‐2‐methylimidazolium–tetraphenylborate ion‐pair was used. The investigated sensor showed a Nernstian response for both dodecylbenzenesulphonate (DBS, 57.6 mV/decade of activity between 5 × 10−7 to 1 × 10−3 M) and sodium lauryl sulfate (LS, 58.4 mV/decade of activity between 2 × 10−7 to 2 × 10−3 M). It responded in 8–10 s for each ten‐fold concentration change in the range of 1 × 10−6 to 3 × 10−3 M. The detection limits for DS and DBS were 2 × 10−7 and 3 × 10−7 M, respectively. The sensor revealed a stable response (signal drift 2.6 mV/h) and exhibited satisfactory selectivity performances for LS over most of the anions generally used in surfactant‐based commercial detergents. The main application of this sensor was the end‐point determination in potentiometric titrations of anionic surfactants. The (diisobutyl phenoxy ethoxy ethyl)dimethyl benzyl ammonium chloride (Hyamine), cetyltrimethylammonium bromide, hexadecylpyridinium chloride monohydrate (HDPC) and 1,3‐didecyl‐2‐methylimidazolium chloride were tested as potential cationic titrants, and all exhibited analytically usable titration curves with well‐defined equivalence points. The standard solution of HDPC was used as a cationic titrant by all potentiometric titrations. The operational life‐time of the sensor described was prolonged to more than 3 months.

Potentiometric Surfactant Sensor Based on 1,3-Dihexadecyl-1H-benzo[d]imidazol-3-ium for Anionic Surfactants in Detergents and Household Care Products

“…Except for the solid state surfactant sensors [6][7][8], they are usually based on the PVC liquid-type sensor membrane incorporated in the electrode body or coated on a wire [9]. Sensor membrane usually consists of a high molecular weight PVC and a plasticizer in a weight ratio 1:2 and an ionophore.…”

Recent advances in applications of surfactant‐based voltammetric sensors

“…CNT‐modified electrodes have exhibited remarkable electroanalytical properties, including low background current, wide potential windows, and high biocompatibility (Gupta et al, 2011). Some studies have been reported based on the use of CNTs in electrochemical sensors to determine different types of electrochemically active materials (Agüí et al, 2008; Jacobs et al, 2010; Sakač et al, 2017). Because of their ability to produce electron transfer reactions with high electrocatalytic effects, they are often used as electrode materials (De Menezes et al, 2011).…”

A Parallel Tool for the Identification of Differentially Methylated Regions in Genomic Analyses

“…Cationic surfactants are used in broad spectra of commercial products as preservatives and disinfectants. Since classical methods for determination of lower surfactant concentrations [1] have many disadvantages, direct potentiometric sensors for surfactants based on ion selective electrodes with liquid membrane type [2,3] offer an elegant, affordable and reliable substitution. Liquid membrane type sensing membranes are typically based on high molecular weight PVC mixed with plasticizer and an ionophore [4].…”

“…The results of potentiometric titrations of cationic surfactants in pharmaceutical disinfectants by DS (c = 4 mM) as titrant and a DMI-TPB sensor containing plasticizer P1 as an indicator, in comparison with the results obtained with referent Direct Potentiometric Surfactant Sensor (DPSS). Average of 5 determinations 2. Direct Potentiometric Surfactant Sensor (DPSS) described in ref [10]…”