A short review on the analysis of the adsorptive behavior of surfactants at carbon paste electrodes for electrochemical sensing

Evaluation of the role of ionic liquid as a modifier for carbon paste electrodes in the detection of anthracyclines and purine-pyrimidine-based anticancer agents

“…Regarding this, carbon paste surely ranks among the materials that are most practical for making modified electrodes. The electrode can be modified by mixing the modifier along with the preparation of the CPE or by electrode immobilization (electrochemically or by various other surface modification techniques [42]. The modification allows the accumulation of the analyte concentration at the electrode interface, thereby enhancing the electrochemical properties.…”

Carbon Paste Electrodes Surface-Modified with Surfactants: Principles of Surface Interactions at the Interface between Two Immiscible Liquid Phases

“…Besides common functioning and use of surfactants in the form of cleaning agents [ 2 ], emulsifiers, or foaming agents [ 3 ], this particular family of chemical compounds has an unquestionable importance in the development of electrochemical sensors, which is also evidenced by myriad of the respective scientific publications [ 4 , 5 , 6 ]. Incorporation of surfactants into the configuration of various electrochemical sensors allows one to utilize highly effective interactions with the analyte that significantly increase its concentration around the sensor surface via electrostatic attraction and, at the same, minimize eventual interferences by electrostatic repulsion [ 7 ]. Also, surfactants can be widely used as additives in working media to improve the solubility of non-polar molecules in mixed or pure organic solvents [ 8 ].…”

“…So far, only a few reports have been devoted to an explanation of why the intentional treatment by surfactants causes a several-fold increase in the current response and a shift of the peak potential to lower values. Besides the already mentioned electrostatic interactions [ 7 ], Kauffmann et al pointed out the removal of a thin layer of the binder from carbon particles by the action of surfactant molecules and called it “carbon paste erosion” [ 13 ], causing a hydrophilization and significant increase in the electrochemically active surface area (ECSA). Moreover, the different wettability of the bare carbon paste layer of a non-polar nature in contrast with a polar surface of surfactant-modified carbon paste can be another interpretation of significantly altered properties of modified CPEs [ 17 ].…”

“…The difference between these two types can be well illustrated in their specific microstructure as shown in Figure 1. In the first variant, the surface of the bare CPE is covered by an adsorbed layer of the molecules of a surfactant, when its hydrophobic tails ("water-hating" moiety) are firmly anchored via extraction into the non-polar binder whereas the hydrophilic heads ("waterloving" part) protrude into the surrounding solution [7,13]. These surface-modified CPEs are stable only in purely aqueous solutions unlike the second variant, bulk-modified CPEs, which are resistant against exposure to organic solvents.…”

“…In addition to this, the surfactants selected for this study were typical compounds from this family of specifically behaving compounds, when our choice reflected also their main types. Therefore, it can be assumed, for example, that all cationic surfactants extracted into the pasting liquid of CPE will to a greater or lesser extent electrostatically attract large anions (potential analytes) from the solution, subsequently form the In the first variant, the surface of the bare CPE is covered by an adsorbed layer of the molecules of a surfactant, when its hydrophobic tails ("water-hating" moiety) are firmly anchored via extraction into the non-polar binder whereas the hydrophilic heads ("waterloving" part) protrude into the surrounding solution [7,13]. These surface-modified CPEs are stable only in purely aqueous solutions unlike the second variant, bulk-modified CPEs, which are resistant against exposure to organic solvents.…”