codeine

This study proposes a new chemiluminescence (CL) method in which chromotrope 2R is an enhancer in acidic potassium permanganate's CL reaction with codeine and pholcodine. Studying the reaction mechanism by UV-Vis, fluorescence, and CL spectra in our previous study showed that chromotrope 2R, after reaction with potassium permanganate, stabilized the Mn(III)-dye complex (Mn(III)- ]3+), making the excited ions of [Mn(III)- ]2+* to be produced more accessible and increase the intensity of the light emitted in the CL reaction. This sensitizing effect was also observed for other compounds such as citric acid, tartaric acid, thiourea, ascorbic acid, naproxen, naltrexone, and oxalic acid. Among these compounds, codeine and pholcodine, which are both antitussive drugs, were selected as analytes in this study. The linear dynamic range (LDR) was found to be 5.0(10-6-4.0(10-3) and 1.0´10-5-1.0´10-3 mol/L, for codeine and pholcodine, respectively. The limit of detection (LOD) for codeine and pholcodine was 1.6´10-6 and 3.4´10-6 mol/L, respectively. The relative standard deviation percentage was calculated at 4.7 and 3.8% for codeine and pholcodine, respectively. To evaluate the effect of dye type on the CL intensity, eight other dyes, including amido black, brilliant blue, orange G, eosin Y, and rhodamine 6G, were also investigated on the CL intensity of codeine and pholcodine. It was found that chromotrope 2R produced the most sensitizing effect. The method was effectively used to determine the codeine in pharmaceuticals and pholcodine in synthetic drug samples.

The CeO2-SnO2/rGO was synthesized and used for modification of glassy carbon electrode (GCE) to measurement of Tramadol (Tra), Codeine (Cod) and Caffeine (Caf). Electrical impedance spectroscopy (EIS) techniques showed that CeO2-SnO2/rGO/GCE has the lower electron transfer resistance (Rct) (63 Ω) in comparison to GCE (223 Ω) and was suitable for electrochemical applications. The synthesized nanomaterials were investigated by some methods such as Transmission electron microscopy (TEM), X-ray Diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The pH value was investigated in the range of 5.5 to 9.5 which the best signal was obtained at pH=6.5. At the CeO2-SnO2/rGO/GCE three oxidation peaks appeared at 0.755, 1.05, and 1.412 V with Ipa= 22.1, 78.4 and 69.49 µA for Tra, Cod, and Caf and the peaks separation of ΔEp (Tra-Cod)=295 mV, and ΔEp (Cod-Caf)=362 mV in the potential region 0.4-1.6 V. In optimum condition, a dynamic range of 0.008-10 μM and 10-270 μM for Tra, 0.01-12 μM and 12-260 μM for Cod, 0.01-14 μM and 14-260 μM for Caf with the detection limit of 0.0056, 0.0053, and 0.0055 μM for of Tra, Cod and Caf, respectively, were obtained. Investigation of effect of scan rate (25 and 300 mV/s) shows that the electrode process was diffusion-controlled. Interference studies show that Li+, Na+, K+, Cl-, Ca2+, Uric acid, Ascorbic acid, Morphine, sucrose, and glucose have no effect on the oxidation current of the analytes. Finally, The presented electrochemical electrode was applied for the measurement of Tra, Cod and Caf in urine and human plasma spiked samples.

In this study, anonymous chemical screening of psychoactive substances (codeine and tramadol) was carried out on urine collected from some students in two Nigerian Universities, coded UN1 and UN2 for a Federal a State University, respectively. Chloroform was used as the extractant and sodium borate was used to adjust the pH of the urine samples to 9. Thin-layer chromatography (TLC) and UV-Visible spectrophotometer was used as the primary separation and quantification methods, respectively. The concentrations of codeine in the urine samples collected from UN1 sick bay ranged from 2.822 ppm to 44.756 ppm, while that of UN2 ranges from 0.289 ppm to 4.434 ppm. The respective concentrations of tramadol for the institutions are within the range of 0.015 ppm to 34.833 ppm and 0.181 ppm to 37.030 ppm. There was a statistical difference (p<0.05) in the use of codeine and tramadol among students attending the selected clinics. It was suggested that the University students be subjected to continuous routine screening and counseling.

A novel chemically modified electrode was constructed based on multi-walled carbon nanotubes, MCM48 molecular sieve composite modified glassy carbon electrode .The modified electrode showed that it can be used for simultaneous determination of acetaminophen (ACT) and codeine (COD), simultaneously. The measurements were carried out by the application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. The fabricated sensor revealed some advantages such as excellent selectivity, good stability and high sensitivity toward ACT and COD determination. Application of DPV method under the optimum conditions showed the modified electrode provides linear responses versus ACT concentrations in the range of 0.2-40 µM and 80-350 µM. The results for COD showed the linear responses in the ranges of 4-70 µM and 150-400 µM respectively using DPV method. The modified electrode was used for determination of ACT and COD in real samples like human blood serum and plasma with satisfactory results.