Screening of citalopram, fluoxetine and their metabolites in human urine samples by gas chromatography-mass spectrometry. A global robustness/ruggedness study.

Capillary gas chromatography with mass spectrometry detection in SIM mode (GC-MS-SIM) has been used for the analysis of citalopram (CIT), fluoxetine (FLX), and all of their metabolites in urine samples. The instrumental parameters affecting GC separation and MS-SIM detection were investigated. A validation procedure was performed on urine matrix and a simultaneous robustness/ruggedness evaluation is also presented in this paper. An optimized solid-phase extraction (SPE) has been applied, reaching in this way to limits of detection (LODs) between 0.7 ng L(-1) (CIT) and 33.6 microg L(-1) (CIT-PA). A pharmacokinetic screening in clinical urine samples has been also carried out.

Micellar electrokinetic capillary chromatography for the determination of fluoxetine and its metabolite norfluoxetine in biological fluids.

A micellar electrokinetic capillary chromatography (MEKC) for determining fluoxetine and its metabolite (norfluoxetine) is proposed. Optimal conditions for the quantitative separation were investigated. A background electrolyte solution consisting of 5 mM phosphate buffer adjusted to pH 12.3 and 40 mM of 1-decanesulfonic acid sodium salt (DSS), hydrodynamic injection and 25 kV of separation voltage were used. Good linearity and precision were obtained for both compounds. Detection limits of 0.2 mg/l for fluoxetine and norfluoxetine were obtained. The developed method is rapid and it has been applied to determine fluoxetine and its metabolite in human serum and urine. The samples were purified and enriched by means of extraction-preconcentration step with a preconditioned C18 cartridge and eluting the compounds with methanol.

Determination of fluoxetine, fluvoxamine, and clomipramine in pharmaceutical formulations by capillary gas chromatography.

A simple and fast capillary gas chromatographic method with flame ionization detection is proposed for the simultaneous determination of fluoxetine, fluvoxamine, and clomipramine without a prederivatization. The reported method is the first one that allows the determination of three selective serotonin reuptake inhibitors. Optimal conditions for the quantitative separation were investigated: column head pressure (80 kPa), injector and detector temperatures (260 and 250 degrees C), time and temperature for the splitless step (0.75 min and 60 degrees C), size of sample (2 microL), and oven temperature program, providing analysis times shorter than 10 min. Aspects such as the stability of the solutions, linearity, accuracy, and precision are examined in order to validate this method. Peak purity and detection and quantitation limits are also assessed using mass selective detection. The scope of the validated method is tested in the analysis of pharmaceutical preparations, with recoveries between 97.5 and 102.5% with regard to their nominal contents.

Resolution of ternary mixtures of Tartrazine, Sunset yellow and Ponceau 4R by derivative spectrophotometric ratio spectrum-zero crossing method in commercial foods.

A very simple spectrophotometric method is described for resolving ternary mixtures of the food colorants Tartrazine, Sunset Yellow and Ponceau 4R by using the first derivative of the ratio spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20 mg l(-1) of Tartrazine (E-102), 40 mg l(-1) of Sunset Yellow (E-110) and 32 mg l(-1) of Ponceau 4R (E-124). Standard deviations of 0.9, 0.8 and 2.4% were obtained for nine standards of 8 mg l(-1) of Tartrazine, 8 mg l(-1) of Sunset Yellow and 8 mg l(-1) of Ponceau 4R, respectively. This method was satisfactorily used for determining synthetic mixtures of these colorants in different ratios (from 1:1:1 to 1:5:5 or even higher) with recoveries in 94-105% range and it was successfully applied over three commercial products containing the three dyes and it did not require any separation step. The results were compared with those obtained by HPLC and very similar values were found by both methods.

Simultaneous determination of tartrazine and sunset yellow by derivative spectrophotometry and ratio spectra derivative.

Two methods for determining Tartrazine and Sunset Yellow in mixtures by first derivative spectrophotometry and by first derivative of the ratio spectra are described. The procedures do not require any separation step. By the first method, the measurements are obtained in the zero-crossing wavelengths and the calibration graphs are linear up to 20 microg/ml of Tartrazine and up to 40 microg/ml of Sunset Yellow. The determinations of Tartrazine and Sunset Yellow are also done by the first derivative of the ratio spectra. The methods are applied for determining both compounds in four commercial food products.