Electrochemical Determination of Morphine in Urine Samples by Tailoring FeWO4/CPE Sensor

Abstract

Morphine (MORPH) is natural alkaloid and mainly used as a pain reliever. Its monitoring in human body fluids is crucial for modern medicine. In this paper, we have developed an electrochemical sensor for submicromolar detection of MORPH. The sensor is based on modified carbon paste electrode (CPE) by investigating the FexW1-xO4 ratio in iron tungstate (FeWO4), as well as the ratio of this material in CPE. For the first time, the effect of the iron–tungsten ratio in terms of achieving the best possible electrochemical characteristics for the detection of an important molecule for humans was examined. Morphological and electrochemical characteristics of materials were studied. The best results were obtained using Fe1W3 and 7.5% of modifier in CPE. For MORPH detection, square wave voltammetry (SWV) was optimized. Under the optimized conditions, Fe1W3@CPE resulted in limit of detection (LOD) of the method of 0.58 µM and limit of quantification (LOQ) of 1.94 µM. The linear operating range between 5 and 85 µM of MORPH in the Britton–Robinson buffer solution (BRBS) at pH 8 as supporting electrolyte was obtained. The Fe1W3@CPE sensor resulted in good selectivity and excellent repeatability with relative standard deviation (RSD) and was applied in real-world samples of human urine. Application for direct MORPH detection, without tedious sample pretreatment procedures, suggests that developed electrochemical sensor has appeared to be a suitable competitor for efficient, precise, and accurate monitoring of the MORPH in biological fluids.

Electrochemical Ultrasensitive Sensing of Uric Acid on Non-Enzymatic Porous Cobalt Oxide Nanosheets-Based Sensor

“…To verify the diffusion-controlled process over the cobalt oxide/GCE electrode, a plot of current peak vs. square root of scan rate is plotted in Figure 4 c. A perfect linear relationship was observed between the square root of the scan rate and the value of the peak current. This further confirms the diffusion-controlled process over the surface of the modified electrode [ 32 , 33 , 34 ].…”

Microspherical Titanium-Phosphorus Double Oxide: Hierarchical Structure Development for Sensing Applications

“…Percentages were calculated as part of graphite powder only, while the percentage of oil was always constant at 20%. After homogenization of the mixture, the home made Teflon body was filled with carbon paste, and the surface of the electrode was cleaned with paper and used without additional purification [ 31 , 32 ].…”

Recent Advances in Electroanalysis Techniques Used for Morphine in Managing Postoperative Pain

“…Recently, iron tungstate (FeWO 4 ) has been used for developing an electrochemical sensor for sub micromolar detection of morphine [28]. The effect of iron-tungsten ratio has been extensively studied for achieving the best possible characteristics and Fe 1 W 3 with 7.5% of modifier in carbon paste electrode showed the best results.…”

“…As found in the literature, morphine and alkaloids are simultaneously determined. The developed electrochemical sensor has appeared to be a suitable competitor for efficient, precise, and accurate monitoring of morphine in biological fluids [28]. There are studies that show the detection of morphine with codeine by the researchers [29,30].…”

“…Figure 5.Square wave voltammograms of morphine at Fe1W3@CPE in absence (green line) and presence (red line) of (A) ascorbic acid (AA); (B) uric acid (UA); (C) citric acid (CA); (D) dopamine (DOP); (E) glucose (GLU); and(F) peak current signal (%) before and after addition of interferents[28].…”