Ultra-high-performance liquid chromatography using a fused-core particle column for fast analysis of propolis phenolic compounds.

Propolis is a bee product with a complex chemical composition formed by several species from different geographical origins. The complex propolis composition requires an accurate and reproducible characterization of samples to standardize the quality of the material sold to consumers. This work developed an ultra-high-performance liquid chromatography with a photodiode array detector method to analyze propolis phenolic compounds based on the two key propolis biomarkers, Artepillin C and p-Coumaric acid. This choice was made due to the complexity of the sample with the presence of several compounds. The optimized method was hyphenated with mass spectrometry detection allowing the detection of 23 different compounds. A step-by-step strategy was used to optimize temperature, flow rate, mobile phase composition, and re-equilibration time. Reverse-phase separation was achieved with a C18 fused-core column packed with the commercially available smallest particles (1.3 nm). Using a fused-core column with ultra-high-performance liquid chromatography allows highly efficient, sensitive, accurate, and reproducible determination of compounds extracted from propolis with an outstanding sample throughput and resolution. Optimized conditions permitted the separation of the compounds in 5.50 min with a total analysis time (sample-to-sample) of 6.50 min.

Rapid method for simultaneous determination of ascorbic acid and zinc in effervescent tablets by capillary zone electrophoresis with contactless conductivity detection.

Ascorbic acid and zinc are essential nutrients that play important roles in nutrition, immune support, and maintenance of health. For this reason, both compounds are widely used as ingredients in dietary supplements. We report, for the first time, an analytical method for fast simultaneous determination of ascorbic acid and zinc. A single analysis run is possible every 80 s (45 injections/h). The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection using a fused silica capillary with 50 cm length (effective length of 10 cm). The separation was achieved by using a background electrolyte composed by 30 mmol/L of 2-(morpholin-4-yl)ethane-1-sulfonic acid and 30 mmol/L of histidine, pH 6.1. The detection limits were 10 and 20 µmol/L and recovery values for spiked samples were 101 and 100% for zinc and ascorbic acid, respectively. The results obtained with the developed procedure were compared to those obtained by titration (ascorbic acid) and flame atomic absorption spectroscopy (zinc), and no statistically significant differences were observed (95% confidence level).

Fast determination of codeine, orphenadrine, promethazine, scopolamine, tramadol, and paracetamol in pharmaceutical formulations by capillary electrophoresis.

Paracetamol is an active ingredient commonly found in pharmaceutical formulations in combination with one of the following compounds: codeine, orphenadrine, promethazine, scopolamine, and tramadol. In this work, we propose a unique analytical method for determination of these active ingredients in pharmaceutical samples. The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation was achieved on a fused silica capillary (50 cm total length, 40 cm effective length, and 50 µm id) using an optimized background electrolyte composed of 20 mmol/L ß-alanine/4 mmol/L sodium chloride/4 µmol/L sodium hydroxide (pH 9.6). Each sample can be analyzed in a single run (≤2 min) and the limits of detection were 2.5, 0.62, 0.63, 2.5, 15, and 1.6 µmol/L for scopolamine, tramadol, orphenadrine, promethazine, codeine, and paracetamol, respectively. Recovery values for spiked samples were between 94 and 104%.

A batch injection analysis system with square-wave voltammetric detection for fast and simultaneous determination of naphazoline and zinc.

In this work, a batch-injection analysis system with square-wave voltammetric (BIA-SWV) detection was applied for the first time to the simultaneous determination of inorganic (zinc) and organic (naphazoline) species. Both compounds were detected in a single run (70 injections h(-1)) with a small injection volume (∼100 µL). The calibration curves exhibited linear response range between 3.0 and 21.0 µmol L(-1) (r=0.999) for naphazoline and between 10.0 and 60.0 µmol L(-1) (r=0.992) for zinc. The detection limits were 0.13 and 0.04 µmol L(-1) for zinc and naphazoline, respectively. Good reproducibility was achieved for multiple measurements of a solution containing both species (RSD<1.0%; n=20). The results obtained with the BIA-SWV method for the simultaneous determination of naphazoline and zinc were compared to those obtained by HPLC (naphazoline) and by FAAS (zinc); no statistically significant differences were observed (95% confidence level).