Development of a method for simultaneous analysis of caffeine and taurine in energy drinks by micellar electrokinetic chromatography with diode-array detector

Determination of ticagrelol in rat plasma and tablets by micellar electrokinetic chromatography coupled with large volume sample stacking: Application to a pharmacokinetic study

A method using micellar electrokinetic chromatography coupled with large-volume sample stacking for the determination of ticagrelol was developed and validated. The analysis was performed in a fused silica capillary (41.5 cm effective length, 50 μm diameter) with ultraviolet detection at 195 nm. The background electrolytes were 30 mM phosphate buffer of pH 3.0 with 120 mM sodium dodecylsulfate and 10 % (v/v) acetonitrile (120 s X 50 mbar; 20°C; -18 kV) and 30 mM borate buffer of pH 8.5 with 75 mM sodium dodecylsulfate (120 s X 50 mbar; 20°C; 25 kV); under acidic and alkaline conditions, respectively. The method was found to be reliable with respect to specificity, linearity of the calibration line (R2  > 0.99), repeatability (relative standard deviation 2.56%-3.34%), and accuracy (recovery in the range 101.21%-102.67%). The limits of detection and quantitation were 0.032, 0.071, and 0.087, 0.188 μg/mL, respectively. The method was successfully applied for the determination of ticagrelol concentrations in rat plasma and tablets with good recoveries and reproducibility. The presented method proved to be suitable for monitoring ticagrelor in rat plasma.

Utilization of 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) as a fluorogenic reagent for the development of a spectrofluorometric assay method for taurine in energy drinks

The development of a simple, inexpensive, sensitive, and selective spectrofluorometric assay method for taurine in energy drinks utilizing 4-fluoro-7-nitro-2,1,3-benzoxadiazole as a fluorogenic agent is described. Conditions affecting the derivatization reaction are investigated and optimized. The optimal conditions are found to be as follows: buffer, pH 10; 4-fluoro-7-nitro-2,1,3-benzoxadiazoleconcentration, 0.05%; reaction time, 30 min; temperature, 50 °C. Fluorescence measurements are carried out at a wavelength of 542 nm, with excitation at a wavelength of 485 nm. The method is validated under the optimum conditions. The method is found to be linear in the range of 2.0–12.5 µg/mL, with a correlation coefficient of 0.9993. The limits of detection and quantification (µg/mL) are 0.6 and 2.02, respectively, which are appropriate for taurine assays in commercial energy drinks. In addition, the proposed method recorded excellent accuracy since the recovery values caused by presence of excipients are found to be in the range of 99.3%–102.87%. The values of relative standard deviation for intra- and inter-day precision were found to be in the ranges of 0.236%–0.659% and 2.12%–2.63%, respectively.

Caffeine content of energy drinks marketed in Brazil

Energy drinks represent a multibillionaire industry that has been growing continuously worldwide. These drinks are especially consumed by young people, athletes, and military personnel due to their claimed "boost" effects. However, there have been concerns about their consumption since incompatibilities regarding the accuracy of the declared caffeine content of these drinks have been reported. Therefore, in this study we have developed a fast and simple method to quantify caffeine in energy drinks. Sample preparation consisted of a dilute-and-shoot process, and analyses were performed by gas-chromatography with nitrogen-phosphorus detector (GC-NPD). The method was applied to quantify caffeine in 37 energy drinks marketed in Brazil. Compared to the labeled caffeine content, 84% of the tested drinks presented caffeine levels in accordance with the specifications. The determined caffeine concentrations ranged from 10 to 67 mg/100 mL, with an average value of 31 mg/100 mL. According to the recommended serving size, no drinks exceeded the safe caffeine daily intake for the general population (400 mg). These findings are more favorable than the results of similar studies. Nevertheless, to avoid caffeine intoxication, energy drink consumers should be aware of three aspects. First, they need to avoid consuming multiple serving doses in short periods of time. Additionally, some energy drinks are labeled as "nutritional supplements", so they may present much more caffeine than similar products commonly regulated as beverages. Finally, despite the growing interest in energy drinks, their consumption by children and early adolescents is being discouraged by the health authorities.

Capillary electromigration methods for food analysis and Foodomics: Advances and applications in the period February 2019-February 2021

This work presents a revision of the main applications of capillary electromigration methods in food analysis and Foodomics. Articles that were published during the period February 2019-February 2021 are included. The work shows the multiple CE methods that have been developed and applied to analyze different types of molecules in foods. Namely, CE methods have been applied to analyze amino acids, biogenic amines, carbohydrates, chiral compounds, contaminants, DNAs, food additives, heterocyclic amines, lipids, secondary metabolites, peptides, pesticides, phenols, pigments, polyphenols, proteins, residues, toxins, vitamins, small organic and inorganic compounds, as well as other minor compounds. The last results on the use of CE for monitoring food interactions and food processing, including recent microchips developments and new applications of CE in Foodomics, are discussed too. The new procedures of CE to investigate food quality and safety, nutritional value, storage and bioactivity are also included in the present review work.