Simple Strategy for Selective Determination of Levamisole in Seized Cocaine and Pharmaceutical Samples Using Disposable Screen‐printed Electrodes

Abstract

Levamisole is the most common adulterant found in cocaine samples and its electrochemical determination in cocaine seized samples is a challenge due to peak overlapping with cocaine. Herein, we propose a deconvolution procedure for levamisole determination in seized cocaine samples using screen‐printed carbon electrodes (SPE). Square‐wave voltammetry in 0.04 mol L−1 Britton Robinson buffered solution (pH 8.0) was selected in combination with optimized SWV parameters (f=8 s−1, a=10 mV and ΔEs=1 mV) to result in the best peak resolution to apply the deconvolution procedure. Deconvoluted responses of levamisole in the presence of cocaine were similar to untreated signals of standard levamisole solutions in absence of cocaine. A linear response was obtained in the range of 20–100 μmol L−1 (r=0.995). The results obtained for the analysis of a seized cocaine sample was statistically similar to that obtained by gas chromatography. Other adulterants found in cocaine street samples (paracetamol, glucose, phenacetin, caffeine, boric acid and lidocaine) did not affect the treated of voltammetric responses of levamisole. A pharmaceutical sample containing levamisole was also analyzed on SPEs and a recovery of 93±2 % was obtained (no deconvolution required for this sample), showing great applicability of SPEs for forensic and pharmaceutical analyses.

Advances in Medical Wearable Biosensors: Design, Fabrication and Materials Strategies in Healthcare Monitoring

“…A similar strategy using carbon-based screen-printed electrodes (SPEs) has been used for other forensic applications, as they are cheap, disposable and have good compatibility with several electrochemical analyzers [ 45 ]. Several authors have used this technique to detect cocaine from body fluids and samples by targeting tertiary amine moiety of cocaine, which requires no incubation and has a rapid response [ 46 , 47 , 48 ]. Carbon-paper electrodes, including molecularly imprinted ones, have been widely used to develop electrochemical sensors for tetrahydrocannabinol (THC) sensing [ 49 , 50 ].…”

Carbonaceous Nanomaterials Employed in the Development of Electrochemical Sensors Based on Screen-Printing Technique—A Review

“…As a result of the industrial scale production of these relatively cheap electrodes, they may be replaced after each analysis. These devices could be used as disposable electrodes or single use in routine or screening measurements [80][81][82][83]. It is of utmost importance when the analysis focuses on complex samples, which may foul or contaminate the electrode surface after only one electrochemical measurement [84].…”

Fullerene/MWCNT/Nafion Modified Glassy Carbon Electrode for the Electrochemical Determination of Caffeine

“…Amongst these methods, the most used are simple chromatographic methods [12] [13] [14], coupled in some cases with mass spectrometry [15] [16]. These techniques are usually expensive and time-consuming when compared to electrochemical methods [17]. However, the high positive oxidation potential of caffeine limits the use of common electrodes such as glassy carbon electrode [18] and carbon paste electrode [19].…”