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A simple and easy liquid chromatographic procedure was developed for the separation and analysis of α,β-arteether. The developed method uses a reversed-phase Luna C18 column (250 mm × 4.6 mm), a hybrid micellar mobile phase containing 0.15 M SDS–6% (v/v) butanol–0.01 M phosphate buffered at pH 7, and detection at 218 nm. Under these conditions, the analysis time was less than 6 min. Validation studies were performed according to the International Conference on Harmonization guideline, including linearity (R2 > 0.9998) in the 0.1–50 µg/mL range, accuracy (99.8–100.8%), repeatability [RSD (%) 1.8–2.8], intermediate precision [RSD (%) 1.8–2.9], and robustness, which were found satisfactory. Method was applied to the determination of α,β-arteether in different pharmaceutical preparations and wrapper/label free ampoules obtaining recoveries in the 97.7–102.2% range. Compared to other chromatographic techniques, micellar liquid chromatography has the advantages of avoiding sample extraction from matrices, thus ...

A high-performance liquid chromatography (HPLC) method with photodiode array detection (PDA) was developed for the determination of three commonly used stupefacients, lidocaine, diazepam, and ketamine, in foodstuff and drinks used for cheating or deceiving a person. The method involves extraction of the selected drugs using ethanol at room temperature. Using the optimum mobile phase of acetonitrile–water (40:60, v/v, pH 3.0, 0.01 M sodium dihydrogen phosphate) and a flow rate of 1.0 mL/min, the separation was achieved on a PrincetonSPHER-100 C18 (250 mm × 4.6 mm, 5 µm particle size) column and UV detection at 252 nm. The limit of detection achieved was 0.025 µg/mL, 0.1 µg/mL, and 0.1 µg/mL for lidocaine, diazepam, and ketamine, respectively. The developed method is simple, precise, and sensitive and could be applied successfully for the determination of laced foodstuff.

A capillary zone electrophoresis method is developed to achieve the separation and determination of two cardiac drugs, trandolapril and verapamil. Optimisation of the method is based on the use of a factorial design, which is applied in order to obtain more information in the factorial space and to minimise the number of experiments needed to obtain the optimum values for the pH and concentration of electrolyte buffer, the voltage applied and the effects of certain modifiers. Following these studies, the conditions selected for use were running buffer of 10 mM phosphate at pH 7.0, and a voltage of 15 kV. Under these conditions, calibration curves were constructed with good linearity (R>0.999) and suitable LODs. The intra‐ and inter‐day repeatabilities were also evaluated with RSD below 4% for trandolapril and verapamil. The proposed method was applied to the determination of verapamil and trandolapril in pharmaceutical formulations and the recoveries obtained were in agreement with the stated con...

The plasma level determination of catecholamines and their metabolites is necessary in studies aimed at evaluating neuroendocrine disorders. A micellar liquid chromatographic procedure was developed for the determination of epinephrine, norepinephrine, and their naturally occurring derivatives, metanephrine and nor‐metanephrine, in serum samples using direct injection. The optimisation studies were performed in a C18 column, using solutions containing sodium dodecyl sulphate (SDS) modified with propanol, butanol, or pentanol as mobile phases. The method proposed for the determination of these catecholamines used a hybrid micellar mobile phase of 0.075 M SDS–1.6% butanol–0.01 M phosphate buffer (pH 7) at 25°C, and electrochemical detection. The serum samples were injected directly without any pretreatment and eluted in 14 min, in accordance with their relative polarities as indicated by their octanol–water partition coefficients. Calibration was linear in the 0.5–50 ng mL−1 range with r 2>0.999. T...

A micellar liquid chromatographic (MLC) procedure was developed for the determination of carbaryl and other carbamates (carbofuran, desmedipham, methiocarb and propoxur), using a C18 column and UV detection. Optimisation was performed using the anionic surfactant sodium dodecyl sulphate (SDS) and the non-ionic Brij-35. Both surfactants yielded similar selectivities, but Brij-35 gives shorter retention times than SDS and for this reason was preferred to speed up the analysis of the carbamates. In the selected mobile phase (0.07 M of Brij-35), the analysis time was 22 min. The procedure was applied for the determination in commercial pesticide formulations and spiked samples (distilled, tap, reservoir tank, irrigation ditch, sea and waste water). This method proved to be competitive against the EPA reference method, recommended for the determination of some N-methylcarbamates, which uses a gradient of acetonitrile. The results of the pesticide formulations obtained with both methods are in agreemen...