A solid-state sensor based on poly(2,4,6-triaminopyrimidine) grafted with electrochemically reduced graphene oxide: Fabrication, characterization, kinetics and potential analysis on ephedrine

Determination of three ephedrine psychoactive substances in sewage using solid-phase extraction-ultra-performance liquid chromatography-tandem mass spectrometry

RATIONALE

In recent years, ephedrine psychoactive substances have attracted much attention due to their prevalence in water bodies and potential threat to aquatic ecosystems. Psychoactive substances have been considered as a new type of environmental pollutant due to their unpredictable potential risks to the behavior and nervous system of non-target organisms. A rapid, sensitive, selective, and robust method for the quantification of three ephedrine psychoactive substances in sewage is needed.

METHODS

An ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of three ephedrine psychoactive substances in water. The optimal processing conditions were determined by optimizing the chromatography-mass spectrometry and solid-phase extraction (SPE) conditions (e.g., the SPE column, sample pH, washing, and elution), and the treatment conditions were determined; this was achieved via positive ion scanning in multiple reaction monitoring mode. Poly-Sery MCX was selected as the extraction column, with samples loaded at pH 3. And 4-mL solution of 2% formic acid (FA) aqueous solution was used as the eluent; the target compounds were eluted with 5 mL of 5% NH4OH in acetonitrile (ACN) solution. The best results were obtained when the residue was resolubulization in ACN after nitrogen evaporation.

RESULTS

The developed UPLC-MS/MS showed a good linear relationship in the range of 0-50.00 μg/L, with determination coefficients (R2) greater than 0.9990. The detection limit and quantitation limit were 0.05-0.10 and 0.20-0.50 μg/L, respectively. Recovery rates of the target compounds in blank sewage at three different concentrations ranged from 92.37% to 106.31%, with relative standard deviations (RSDs) of 0.77%-4.83% (n = 7).

CONCLUSIONS

This method has been successfully applied to the analysis of surface water and domestic sewage, and the samples were processed stably, indicating that the method is practical for the determination of ephedrine psychoactive drugs in water bodies.

Electrochemical study of ephedrine at the polarized liquid-liquid interface supported with a 3D printed cell

In this work, we have examined an electrochemical behavior of the ephedrine at the polarized liquid-liquid interface (water/1,2-dichloroethane). In this respect, we first designed and then 3D printed polyamide-based electrochemical cell that was used as the liquid-liquid interface support during electroanalytical measurements. The protonated ephedrine undergoes a reversible ion transfer reaction with the standard Galvani potential difference equal to +0.269 V. This value was used to calculate the water - 1,2-dichloroethane logP equal to -4.6. Ion transfer voltammetry was used to build the calibration curve and allowed for the ephedrine detection from concentration equal to 20 μM. By varying the pH of the aqueous phase from 2 up to 12 we were able to plot the ion partition diagram that was further analyzed and provided several pharmacochemical information. To further push this work towards practical utility, we have formulated the artificial urine and studied the interfacial behavior of all its components at the polarized liquid-liquid interface. Ephedrine detection from real spiked urine samples was also performed.

The Development of Spectrophotometric and Validated Stability- Indicating RP-HPLC Methods for Simultaneous Determination of Ephedrine HCL, Naphazoline HCL, Antazoline HCL, and Chlorobutanol in Pharmaceutical Pomade Form

BACKGROUND

Allergic rhinitis, acute nasal congestion and sinusitis are one of the most common health problems and have a major effect on the quality of life. Several medications are used to improve the symptoms of such diseases in humans. Pharmaceutical pomade form containing Ephedrine (EPD) HCl, Naphazoline (NPZ) HCl, Antazoline (ANT) HCl, and Chlorobutanol (CLO) is one of them.

OBJECTIVE

For these reasons, this study includes the development of spectrophotometric and chromatographic methods for the determination of EPD HCl, NPZ HCl, ANT HCl, and CLO active agents in the pharmaceutical pomade.

METHOD

In the spectrophotometric method, third-order derivative of the amplitudes at 218 nm n=5 and the first-order derivative of the amplitudes 254 nm n=13 was selected for the determination of EPD, ANT, respectively while NPZ was determined by the second derivative at 234 nm and n=21. Colorimetric detection was applied for assay analysis of CLO at 540 nm. Furthermore, a reverse phase high performance liquid chromatographic (RP- HPLC) method has been developed and optimized by using Agilent Zorbax Eclipse XDB C18 (75 mm x 3.0 mm, 3.5μm) column. The column temperature was 40°C, binary gradient elution was used and the mobile phase consisted of 15 mM phosphate buffer in distilled water (pH 3.0) and methanol, and the flow rate was 0.6 mL min^-1 and the UV detector was detected at 210 nm. The linear operating range was obtained as 11.97-70, 0.59-3, 2.79-30, and 2.92-200 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO respectively.

RESULTS

The LOD values were found to be 3.95, 0.19, 0.92 and 0.96 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in the spectrophotometric method, respectively. The linear ranges in the RP-HPLC method were 8.2-24.36 μg mL^-1, 0.083 - 0.75 μg/mL, 2.01-7.5 μg mL^-1 and 2.89-24.4 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO, respectively. The LOD values in the validation studies were 2.7, 0.025, 0.66 and 0.86 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in RP-HPLC method respectively.

CONCLUSION

The results of the spectrophotometric and chromatographic methods were compared and no differences were found between the two methods.