Chromatography-diode Array Detection Research Articles

Solvent bar microextraction combined with HPLC-DAD and multivariate optimization for simultaneous determination of three antiarrhythmic drugs in human urine and plasma samples

A sensitive and simple microextraction approach was developed and validated to simultaneously determine three antiarrhythmic drugs, propranolol, diltiazem, and verapamil, in human urine and plasma samples, by combining solvent bar microextraction (SBME) with high-performance-liquid- chromatography diode-array detection. The optimization of SBME was initially investigated following a full factorial design (FFD) and subsequently by central composite design (CCD). With only 27 extraction tests using CCD, the optimum extraction conditions for selected drugs by SBME methodology were determined. The CCD allowed examining the linear, interaction, and quadratic influence of factors on drugs’ extraction efficiencies% (EE%), resulting in reduced size of SBME experiments. Under the optimal conditions, the calibration curves were linear in the ranges of 1.73–103 / 2.56–103 μg L−1 for propranolol, 2.32–103/ 2.83–103 μg L−1 for diltiazem, and 4.54–103/ 5.97–103 μg L−1 for verapamil at the respective urine/ plasma samples with reasonable linearity R2 > 0.978 in both matrixes. The ranged value of intra precision (RSD%, n = 5) for the selected drugs were from 1.30 to 5.66 and from 3.00 to 7.80 in urine and plasma samples, respectively. The limits of detection in urine/ plasma were 0.52/ 0.77 μg L−1, 0.69/ 0.84 μg L−1, 1.36/ 1.79 μg L−1 for propranolol, diltiazem, and verapamil, respectively. In comparison with referenced methods and based on the satisfactory results of applications, the proposed method can be considered a potential method for biopharmaceutical analysis of selected antiarrhythmic drugs in biological samples.

Influence of Seasonality and Sunlight Effects on Rollinia mucosa Leaves Fingerprint

Rollinia mucosa fruit has generated great interest due to the presence of bioactive compounds, which exhibit promising biological activities. Fingerprinting analytical techniques, chromatographic-diode array detection (DAD), infrared, mass spectrometric, 1H and 13C nuclear magnetic resonance (NMR) spectra, associated with chemometric analysis and mixture design, were used to determine chemical discriminations of sun-exposed and self-shaded leaves of Rollinia mucosa in each of the four seasons. Sunlit leaves in winter presented higher metabolite signals related to the acetogenins, whereas shaded leaves have higher abundances of carbohydrates and terpenes. Sunlit leaves harvested in the summer had the smallest metabolite abundances. Fingerprints confirmed the presence of two acetogenins, annonacin A and annonastatin. Ternary and quaternary mixtures of the statistical mixture design were most effective for revealing important discriminations.

Anthocyanidin 3-galactosides from flowers of Abrus canescens Bak

Three anthocyanins, the 3-galactoside of delphinidin (1) (8.5 %), petunidin (2) (9.2 %) and malvidin (3) (73.8 %) were isolated from the deep red-purple flowers of Abrus canescensby a combination of chromatographic techniques. Their structures were elucidated by on-line diode array detection chromatography and homo- and hetero-nuclear magnetic resonance (NMR) techniques. Key words: Abrus canescens, Fabaceae, anthocyanin, malvidin 3-galactoside, petunidin 3-galactoside, delphinidin 3-galactoside, taxonomy.

High-performance liquid chromatography (HPLC) determination of inosine, a potential biomarker for initial cardiac ischaemia, using isolated mouse hearts

Each year in the USA approximately 7–8 million patients with non-traumatic chest pain come to hospital emergency rooms. It is estimated that approximately 2–5% of these patients are experiencing cardiac ischaemia, but due to the shortcomings of the available testing methods they are incorrectly diagnosed and discharged without appropriate therapy having been provided. Preliminary data with a globally ischaemic mouse heart model has demonstrated that endogenous inosine might be a potential biomarker of initial cardiac ischaemia before cardiac tissue necrosis. A high-performance liquid chromatographic diode array detection (HPLC-DAD) method was utilized for the detection and quantification of inosine in Krebs–Henseleit (Krebs) buffer solution perfusing from surgically removed and isolated mouse hearts undergoing global cardiac ischaemia. A C18 column at a flow rate of 0.6 ml min−1 with an aqueous mobile phase of trifluoroacetic acid (0.05% trifluoroacetic acid in deionized water, pH 2.2, v/v) and methanol gradient was used for component separation. The assay detection limit for inosine in Krebs buffer solution was 500 ng ml−1 using a 100-µl neat injection. The HPLC results were used to determine total cardiac effluxed inosine into the Krebs effluent for each mouse during oxidative stress and compared with the per cent cardiac ventricular functional recovery rate to determine if a relationship exists amongst this cardiovascular parameter during periods of cardiac oxidative stress.