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The effects of organic modifiers—alcohols (methanol, isopropanol), acetonitrile, and tetrahydrofuran—and β-cyclodextrins in capillary zone electrophoresis were investigated using a test mixture containing five biogenic amines important from the human health point of view—serotonin, dopamine, adrenaline, noradrenaline, and tyramine—and two B vitamins—thiamine and pyridoxine. The simultaneous addition of tetrahydrofuran and isopropanol was found to improve the resolution of determined analytes and enable effective separation of analytes with very similar electromigration characteristics migrating as one peak (dopamine and serotonin). The developed and optimised separation method based on capillary zone electrophoresis and ultraviolet detection was capable to achieve detection limits at the concentration level in the range of 0.15 to 1.25 μg/mL−1. The developed method was also characterised by other favourable validation parameters, such as linearity (r2 > 0.99), accuracy (82.9–117.8% for the intraday measurements, and 87.6–119.2% for the interday measurements), and precision (intraday relative standard deviation in the range of 0.4–15.5%, interday relative standard deviation in the range of 0.9–18.3%). The method was finally applied to investigate the stability of the analytes in model water matrix samples under various storage conditions.

The application of hydrodynamically closed capillary zone electrophoresis combined with convenient ultraviolet (UV) detection allows fast, simple, environmentally friendly and cost-effective analysis of ions or ionisable molecules. This technique has been used to determine two selected B vitamins (thiamine, pyridoxine) in various drug formulations. The developed method was characterised by excellent validation parameters, such as linearity, precision, accuracy, limit of detection and limit of quantification. The total time of analysis was lower than 13.5 min. The results indicate that the method is suitable for implementation in routine quality control of selected B vitamins in pharmaceutical and food samples.

The pseudo-fruits of Dog Rose are a rich source of L-ascorbic acid and several other active substances, which means their high supportive therapeutic potential. The study aimed to examine the impact of the chosen technological procedure for the preparation of tablets containing rosehip powder on the amount of L-ascorbic acid in the final pharmaceutical form. Drying of the plant drug was performed at room temperature to avoid possible thermal degradation of this heat-sensitive compound. Similarly, drying of the granules after wet granulation in the oven was replaced by natural drying at room temperature. The composition of two types of prepared granule formulations differed in the filler – lactose (LAC) or microcrystalline cellulose (MCC). Apart from the disintegration test, they meet the technological requirements for granules or tablets. Lactose was confirmed as a more suitable filler, which despite the unsuccessful disintegration of the granules, ensures the disintegration of tablets within 15 minutes even without the addition of a special excipient acting as a disintegrant. The content of L-ascorbic acid detected using isotachophoresis – capillary zone electrophoresis was 87.16 ± 5.06 µg in LAC tablets and 63.33 ± 2.83 µg in MCC tablets.