Electrified Soft Interface as a Selective Sensor for Cocaine Detection in Street Samples

Abstract

A straightforward, direct, and selective method is presented for electrochemical cocaine identification in street samples. The sensing mechanism is based on a simple ion transfer reaction across the polarized liquid–liquid interface. The interfacial behavior of a number of cutting agents is also reported. Interfacial miniaturization has led to improved electroanalytical properties of the liquid–liquid interface based sensor as compared with the macroscopic analogue. The reported method holds great potential to replace colorimetric tests with poor selectivity for on-site street sample analysis.

Electrochemical cocaine (bio)sensing. From solid electrodes to soft junctions

“…4A for schematic) [49]. In the recent report by Poltorak et al, ITIES was used as the screening device for cocaine detection in the presence of a number of cutting agents used to adulterate street samples [50]. In such a configuration, as shown in Fig.…”

Voltammetry of Several Natural and Synthetic Opioids at a Polarized Ionic Liquid Membrane

“…[11][12][13][14] Biolanalytical applications of electrolysis at microITIES, including studies on neurotransmitters, amino acids, peptides, drugs and biomacromolecules, have been reviewed, [15] Methodological progress in realizing microITIES [16] has led to an improved detection of cocaine in street samples containing a mixture of the drug and a cutting agent. [17] Folowing the pioneering study, [18] the ionic liquids (ILs), which are composed of highly hydrophobic cations and anions such as tridodecylmethylammonium tetrakis[3,5-bis(trifluoromethyl) phenyl]borate (TDMATFPB), have been successfully tested as alternatives to the solutions of the hydrophobic electrolytes in a molecular organic solvent, e. g., 1,2-dichloroethane (DCE), used in the electrochemical experiments at the ITIES. [19][20][21] Voltammetric measurements at a supported IL membrane have provided a broad range of both theoretical and practical results of the electrochemical or analytical significance.…”

“…Electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) has proved to be a useful tool for investigating the transport of ions through the liquid/liquid boundaries [11–14] . Biolanalytical applications of electrolysis at microITIES, including studies on neurotransmitters, amino acids, peptides, drugs and biomacromolecules, have been reviewed, [15] Methodological progress in realizing microITIES [16] has led to an improved detection of cocaine in street samples containing a mixture of the drug and a cutting agent [17] . Folowing the pioneering study, [18] the ionic liquids (ILs), which are composed of highly hydrophobic cations and anions such as tridodecylmethylammonium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate (TDMATFPB), have been successfully tested as alternatives to the solutions of the hydrophobic electrolytes in a molecular organic solvent, e. g., 1,2‐dichloroethane (DCE), used in the electrochemical experiments at the ITIES [19–21] .…”

Quantitative Analysis of Redox-Inactive Ions by AC Voltammetry at a Polarized Interface between Two Immiscible Electrolyte Solutions

“…The primary electrochemical techniques used to date to generate the electroanalytical signal at the ITIES in the presence of redox-inactive ions are amperometry [46][47][48][49][50][51][52] and voltammetry (cyclic voltammetry (CV) 8,16,28,[53][54][55] and differential pulse voltammetry (DPV), 21,40,56,57 respectively). Successful application of these methods to achieve precise quantitative analysis at the macroITIES can be hampered by the presence of interfering capacitive currents, background currents due to residual ion transfer of the aqueous electrolyte across the full polarisable potential window (PPW), and the inherently high resistance of a liquid|liquid (L|L) electrochemical cell due to the presence of an organic phase.…”