Heroin detection in a droplet hosted in a 3D printed support at the miniaturized electrified liquid-liquid interface

Abstract

Simple sensing protocols for the detection of illicit drugs are needed. Electrochemical sensing is especially attractive in this respect, as its cost together with the analytical accuracy aspires to replace still frequently used colorimetric tests. In this work, we have shown that the interfacial transfer of protonated heroin can be followed at the electrified water-1,2-dichloroethane interface. We have comprehensively studied the interfacial behavior of heroin alone and in the presence of its major and abundant cutting agents, caffeine and paracetamol. To maximally increase developed sensing protocol applicability we have designed and 3D printed a platform requiring only a few microliters of the aqueous and the organic phase. The proposed sensing platform was equipped with a cavity hosting a short section of Ag/AgCl electrode, up to 20 µL of the aqueous phase and the end of the micropipette tip being used as a casing of a fused silica capillary having 25 µm as the internal pore diameter. The volume of the organic phase was equal to around 5 µL and was present inside the micropipette tip. We have shown that under optimized conditions heroin can be detected in the presence of caffeine and paracetamol existing in a sample with 10,000 times excess over the analyte of interest. The calculated limit of detection equal to 1.3 µM, linear dynamic range spanning to at least 50 µM, good reproducibility, and very low volume of needed sample is fully in line with forensic demands.

Applications of Electrochemistry at the ITIES in Drug Discovery and Development – A Review

“…The low production costs of the cell and the low organic solvent volume required to perform the experiments can be very appealing for high throughput work. That is the case of 3D printed platforms that were fabricated to perform ITIES studies in a single microliter water droplet (volume up to 20 μL only) [70] . In another work, the same research group used thermally oxidized thin aluminum films as inexpensive support for the ITIES.…”

“…The more representative works are resumed in Table 1, including the relevant standard ion-transfer potential and the obtained partition coefficients (log P) of the charged and neutral forms of the compound (when available). In these studies, the most widely used solvent as organic phase was by far the DCE [59,[61][62][63][64][65][66][67][68][69][70][71] although in some works DCH [49,72] was used. For accurate measurement of the formal transfer potential during the ITIES assay, differential pulse voltammetry (DPV) technique [49,59,62,72] was often selected since it provides better well-defined peak shaped voltammograms comparing with CV.…”

Electroanalytical characterization of clozapine at the electrified liquid–liquid interface and its detection in soft and hard drinks

“…The portability of electro-chemical sensors makes them an ideal candidate for rapid onsite screening of various illicit drugs ranging from cocaine to morphine, heroin, etc., in biological and street samples. [9][10][11][12] Particularly, the notable achievements in the electrochemical sensing of BDZ drugs include the use of easily operative comprehensive electrochemical test strips for on-site detection of CZ in biomedical samples promoting its reliabilities for clinical analysis. 13,14 Despite the impressive success of electroanalytical platforms focused on CZ detection in biological samples, its electroanalysis in complex DFSA samples, in particular hard and soft drinks, has not been much explored yet.…”

Electrochemical screening of selected β-blockers at a polarized liquid–liquid interface

“…31,32 ITIES-based electrochemical sensors have been used for the determination of biologically active substances including pharmaceuticals and drugs. 30,[33][34][35][36] Also, several published works described β-blocker determination at the ITIES. The work by Courtney J.…”

“…31,32 ITIES-based electrochemical sensors have been used for the determination of biologically active substances including pharmaceuticals and drugs. 30,33–36 Also, several published works described β-blocker determination at the ITIES. The work by Courtney J. Collins and Damien W. M. Arrigan describes propranolol electroanalytical detection at a silicon membrane-based liquid–liquid microinterface in artificial saliva with a concentration as low as 20 nM.…”