Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
This study presents an electrochemical sensor developed from a glassy carbon electrode modified with nanodiamond film (ND/GCE). This electrochemical response of the proposed sensor was improved, and it showed excellent analytical performance for the detection of paracetamol (PAR), which was attributed to the high PAR charging capacity on the electrode surface and the excellent electrical conductivity of ND. Morphological and electrochemical characterizations of the sensor were performed via scanning electron microscopy (SEM) and cyclic voltammetry using a redox probe [Fe(CN)6]3−. The sensor was applied for the determination of PAR. Quantification was performed using square-wave voltammetry, and it showed a linear concentration range from 0.79 to 100 μmol L−1, with a limit of detection of 0.18 μmol L−1. The proposed sensor exhibited satisfactory repeatability and high sensitivity in the determination of the analyte of interest. The electrochemical sensor was also employed for the analysis of PAR in real samples, with recovery rates ranging between 96.4 and 98.7%. This sensor was successfully used for the determination of the drug in pharmaceutical samples....
In recent years, the detection of nitrosamine precursors has become an important issue for regulatory authorities such as the European Medicines Agency (EMA) and the Food and Drug Administration (FDA). The present study provides a pre-column derivatization method for the analysis of dimethylamine (DMA) and diethylamine (DEA) in pharmaceutical products using HPLC and a fluorescence detector. Appropriate chromatographic parameters, including mobile phase composition (organic solvent, buffer, pH), elution type, flow rate, temperature, and λexcitation/emission, were investigated. Analysis was performed at λexcitation = 450 nm and λemission = 540 nm on a C18 column (at 40 ◦C) using gradient elution as a mobile phase with Eluent A: Phosphoric Acid Buffer (20 mM, pH = 2.8) and Eluent B: methanol, with a flow of 0.8 mL/min. The method was validated according to ICH specifications in terms of linearity (0.5–10 ng/mL for DMA and 5–100 ng/mL for DEA), specificity, and robustness, as well as repeatability, intermediate precision (%RSD < 2.9), and accuracy (% recovery 98.2–102.0%). The derivatization process was optimized using the “Crossed D-Optimal” experimental design procedure, where one mixture component was cross-correlated with two factors. The stability of the samples was studied over a period of one month. To process the samples (pharmaceuticals), various purification techniques were tried using solid/liquid or liquid/liquid extraction with dichloromethane. Finally, a straightforward solid-phase extraction (SPE, C18) method was chosen prior to derivatization. The method was successfully applied, since the extraction recoveries were >81.6% for DMA (0.5 ppm) and >81.1% for DEA (5 ppm). Based on the results obtained and the available literature, the scientific community seeks, by proposing flexible analytical methods, to delimit the problem of nitrosamines....
A simple, cost-effective, and efficient novel high-performance thin-layer chromatography (HPTLC) tool was developed and validated in accordance with International Conference on Harmonisation (ICH) guidelines for the detection and quantification of four fat-soluble vitamins, D2, D3, E, and K1, using chloroform: cyclohexane (55:45, v/v) as mobile phase. The detection and quantification limits were found to be 30.86 and 93.52 ng/band for vitamin D2, 19.44 and 58.92 ng/band for vitamin D3, 14.17 and 42.95 ng/band for vitamin E, and 0.86 and 2.61 ng/band for vitamin K1, which were similar or lower than those reported in previous methods. The advantage of the developed method is that it uses a simple mobile phase in a single development step and has low detection and quantification limits. The application of the developed HPTLC method was successfully demonstrated with the quantitative analysis of these vitamins in some commercially available pharmaceutical preparations....
Background: Honey is one of the most adulterated foods worldwide, and several analytical methods have been developed over the last decade to detect syrup additions to honey. These include approaches based on stable isotopes and the specific detection of individual marker compounds or foreign enzymes. Proton nuclear magnetic resonance (1H-NMR) spectroscopy is applied as a rapid and comprehensive screening method, which also enables the detection of quality parameters and the analysis of the geographical and botanical origin. However, especially for the detection of foreign sugars, 1H-NMR has insufficient sensitivity. Methods: Since untargeted liquid chromatography– mass spectrometry (LC-MS) is more sensitive, we used this approach for the detection of positive and negative ions in combination with a recently developed data processing workflow for routine laboratories based on bucketing and random forest for the detection of rice, beet and high-fructose corn syrup in honey. Results: We show that the distinction between pure and adulterated honey is possible for all three syrups, with classification accuracies ranging from 98 to 100%, while the accuracy of the syrup content estimation depends on the respective syrup. For rice and beet syrup, the deviations from the true proportion were in the single-digit percentage range, while for high-fructose corn syrup they were much higher, in some cases exceeding 20%. Conclusions: The approach presented here is very promising for the robust and sensitive detection of syrup in honey applied in routine laboratories....
The study highlights the need for quality control in evaluating medicinal plant products, especially CBD oils, before market release. Due to varying regulatory requirements, product labeling can sometimes be misleading, especially regarding cannabinoid concentrations such as CBD and THC. This research focused on developing a validated high-performance liquid chromatography (HPLC) method for accurately identifying and quantifying key cannabinoids in Commercial Veterinary CBD Oil. The main compounds identified included Cannabidivarin (CBDV), Cannabidiolic Acid (CBD-A), Cannabigerolic Acid (CBG-A), Cannabigerol (CBG), Cannabidiol (CBD), Tetrahydrocannabivarin (THCV), Cannabinol (CBN), Δ9-Tetrahydrocannabinol (d9-THC) Δ8-Tetrahydrocannabinol (d8-THC), Cannabicyclol (CBL), Cannabichromene (CBC), and Tetrahydrocannabinolic Acid (THCA), determined in line with the International Conference on Harmonization’s (ICH) guidelines. The method was validated for linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). It was determined to be linear, with a correlation coefficient (R²) > 0.999. The LOD and LOQ values calculated from the calibration curve ranged from 0.05 to 0.13 and 0.50 to 0.61 μg/mL, respectively. The method also exhibited acceptable precision, with relative standard deviation values lower than or equal to 2%. The method’s accuracy was assessed through recovery percentages and fell within an acceptable range of 98–102 if the RSD was 2%. This study’s rigorous methodology and comprehensive findings significantly contribute to cannabinoid analysis. This validated protocol was used to analyze cannabinoids in 14 commercial veterinary CBD oil products from the Republic of North Macedonia. The performance parameters demonstrated that the method is reliable for quantitatively measuring cannabinoids in CBD oil. The analysis showed that the cannabinoid levels in the products were consistent with the manufacturers’ declared specifications, with no significant discrepancies in labeling....
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